Vice President Global Coverage and Reimbursement Global Health Economics
Transcription
Vice President Global Coverage and Reimbursement Global Health Economics
Joshua Ofman, MD, MSHS Vice President Global Coverage and Reimbursement Global Health Economics Global Government Affairs 601 Thirteenth Street, NW 12th Floor Washington, DC 20005 www.amgen.com December 20, 2010 Maria Ellis Executive Secretary for MEDCAC Centers for Medicare & Medicaid Services Office of Clinical Standards and Quality, Coverage and Analysis Group C1-09-06 7500 Security Boulevard Baltimore, MD 21244 Re: Medicare Program; Meeting of MEDCAC, January 19, 2011, on Erythropoiesis Stimulating Agents (ESA) in Anemia Related to Kidney Disease Dear Ms Ellis: Amgen Inc. (Amgen) is writing to comment on the topics to be addressed at the Medicare Evidence Development and Coverage Advisory Committee (MEDCAC) January 19, 2011 meeting on Erythropoiesis Stimulating Agents (ESA) in anemia related to chronic kidney disease (CKD), which the Centers for Medicare & Medicaid Services (CMS) published notice of on October 26, 2010 on the website, http://www.cms.gov/mcd/viewtrackingsheet.asp?id=245. ESAs are indicated for the treatment of anemia associated with chronic renal failure (CRF), including patients on and not on dialysis and Amgen’s comments will be provided separately for these two patient populations. As a science-based, patient-care driven company, Amgen is committed to using science and innovation to dramatically improve people’s lives and is vitally interested in improving access to innovative drugs and biologicals for Medicare beneficiaries. Attached, you will find our detailed written submission addressing the effects of ESAs on health outcomes in adult CKD patients, both on dialysis and not on dialysis. In particular, we call your attention to Appendix A, which specifically addresses the voting questions posted on the CMS website on November 24, 2010, and Appendix C, which provides an independent review commissioned by Amgen of the clinical literature specific to the effects of blood transfusions on renal transplant graft survival. By way of additional background, Amgen recently developed and submitted the following materials containing important clinical information regarding the overall effects of ESAs on health outcomes in adult CKD patients: • March 24, 2010 MEDCAC Meeting - Erythropoiesis Stimulating Agents (ESA) in Anemia Related to Kidney Disease; http://www.amgen.com/media/amgen_medcac_esa_meeting.html • October 18, 2010 US Food and Drug Administration’s Cardiovascular and Renal Drugs Advisory Committee (CRDAC) meeting on the benefits and risks of ESAs in patients with CKD, not on dialysis; http://www.amgen.com/media/statement_on_briefing_docs_TREAT_review.html. Amgen appreciates the opportunity to provide this important information and looks forward to the opportunity to discuss the evidence for ESAs in patients with CKD at the upcoming MEDCAC. If you have any questions or need additional information, please do not hesitate to contact me. Regards, Joshua J. Ofman, MD, MSHS Vice President, Global Coverage and Reimbursement and Global Health Economics Page 3 of 290 MEDCAC Background Information Page 1 BACKGROUND INFORMATION FOR THE MEDICARE EVIDENCE DEVELOPMENT AND COVERAGE ADVISORY COMMITTEE JANUARY 19, 2011 BRIEFING MATERIALS DESCRIBING CURRENTLY AVAILABLE EVIDENCE ON THE USE OF ERYTHROPOIESIS STIMULATING AGENTS (ESAs) TO MANAGE ANEMIA IN PATIENTS WHO HAVE CHRONIC KIDNEY DISEASE (CKD) Submitted: DECEMBER 20, 2010 Amgen Inc. One Amgen Center Drive Thousand Oaks‚ CA 91320-1799 Page 4 of 290 MEDCAC Background Information Page 2 Table of Contents 1. EXECUTIVE SUMMARY.......................................................................................... 7 2. BACKGROUND AND INTRODUCTION ................................................................ 10 2.1 Patients with CKD Requiring Dialysis Differ Substantially From Patients Who Do Not Require Dialysis ....................................................... 10 3. ANEMIA IN DIALYSIS PATIENTS ......................................................................... 11 3.1 Anemia is Severe, Nearly Universal, Highly Symptomatic and Associated with Significantly Decreased Physical Functioning, Exercise Tolerance and Health Related Quality of Life in Dialysis Patients....................................................................................................... 11 3.2 Severe Anemia Requires Therapeutic Intervention to Alleviate the Substantial Symptoms .......................................................................... 12 3.3 Transfusions Are Only Transiently Effective In Dialysis Patients Who Are Chronically Unable To Produce Sufficient Red Blood Cells, And Transfusions Carry A Range Of Acute And Chronic Risks ........................................................................................................... 12 3.3.1 Transfusions Are Recognized As Having Intrinsic Risks .......................................................................................... 14 3.3.2 Transfusions Can Transmit Infectious Diseases ........................ 14 3.3.3 Transfusions Can Cause Volume Overload, Hyperkalemia, Transfusion Reactions, And Transfusion-Related Acute Lung Injury (TRALI) ........................ 15 3.3.4 Transfusions Can Cause Iron Overload ..................................... 16 3.3.5 Transfusions Can Result In Sensitization, Which Compromises Transplant Eligibility And Graft Survival .............. 17 3.3.5.1 Transplant Is The Preferred Treatment Strategy For End-Stage Renal Disease: Delayed Transplantation Decreases Both Patient And Graft Survival........................................ 17 3.3.5.2 Techniques In Characterizing Immunologic Impediments To Successful Transplantation ........................................................ 19 3.3.5.3 The Role Of Transfusions In The Development Of Allosensitization ............................ 23 3.3.5.4 Impact Of Transfusions And Allosensitization On Transplant Opportunities And Outcomes ................................... 24 3.3.5.5 Donor-Specific Transfusions And Transplant Outcomes Among Living Donor Kidney Transplants .................................................. 27 3.3.5.6 Management Of Patients With High Levels Of Donor-Specific Antibodies ................................... 27 MEDCAC Background Information 3.4 4. Page 5 of 290 Page 3 ESA Therapy Reduces The Need For Recurrent RBC Transfusions And Their Attendant Risks By Effectively Raising And Maintaining Hemoglobin Concentrations And Improving Physical Function, Exercise Tolerance And The Symptoms Of Anemia ....................................................................................................... 28 3.4.1 ESA therapy reduces the need for transfusions when used to raise Hb ≥ 10 g/dL and maintain it between 10-12 g/dL .................................................................................. 28 3.4.2 ESAs Reduce The Frequency And Impact Of Transfusion Related Risks ......................................................... 30 3.4.3 ESAs Improve Physical Function and Exercise Tolerance When Used to Raise Hb ≥ 10 g/dL and Maintain it Within the Approximate Range of 10-12 g/dL ............................................................................................ 31 3.4.4 ESAs Should be Considered in the Context of their Labeled Risks ............................................................................. 35 3.4.5 Substantial Evidence Supports the ESA Labeled Hemoglobin Range of 10-12 g/dL in Dialysis Patients ............... 36 3.4.5.1 The Need for Transfusions Decreases Substantially when Hb Concentrations are Raised ≥ 10 g/dL and Maintained Within the Range of Approximately 10-12 g/dL with ESA Therapy .................................................... 36 3.4.5.2 A Two Gram Hb Range is Appropriate when Titrating ESA Doses to Maintain Hb Concentrations Above 10 g/dL................................. 38 3.4.5.3 ESAs Have a Broad Dose-Response and There is no Evidence Supporting a Single Maximum Dose ........................................................ 39 3.4.5.4 The Current ESA Label Provides Conservative Dosing Guidance for Patients Who Do Not Adequately Respond to ESA Therapy........................................................ 39 3.4.6 There are No New Data in Dialysis Patients to Support a Change in the Labeled Hemoglobin Range of 10-12 g/dL and Data from Clinical Trials and Over 20 years of Clinical Experience Support this Range ................................. 40 3.4.7 The Prospective Payment System (PPS) will Impact the Use of ESAs ......................................................................... 41 3.4.8 Conclusion: ESAs are an Essential Therapy for Dialysis Patients ......................................................................... 42 ANEMIA MANAGEMENT IN CKD PATIENTS NOT ON DIALYSIS ....................... 43 4.1 CKD-NOD Patients are Heterogeneous with Respect to Kidney Function, Prevalence and Severity of Anemia, and there is a Sub-Population who May Require Anemia Management ........................... 43 4.2 Transfusions are Not Uncommon in CKD-NOD Patients with Significant Anemia ...................................................................................... 44 Page 6 of 290 MEDCAC Background Information 4.3 4.4 4.5 4.6 Page 4 RBC Transfusions Carry Similar Risks in CKD-NOD and Dialysis Patients....................................................................................................... 44 ESAs are an Effective Therapy for Managing Anemia in CKDNOD Patients.............................................................................................. 45 ESAs should be considered in light of their labeled risks ........................... 46 Conclusion: ESA Therapy in CKD-NOD Patients is an Important Treatment Option in Those With Significant Anemia and for Whom Transfusion Avoidance is a Meaningful Clinical Outcome .............. 46 5. CONCLUSION ....................................................................................................... 47 6. REFERENCE LIST................................................................................................. 48 Appendix A - CMS Questions and Amgen's Responses ..................................................60 Appendix B - Select References ......................................................................................90 Appendix C - Independent Review of the Clinical Literature ..........................................251 Appendix D - Guidelines for Blood Transfusion .............................................................287 List of Figures Figure 1. Pattern of Transient Improvements in Hb Concentrations Following Transfusions in a Dialysis Patient ............................................................ 13 Figure 2. Rate of Hospitalization or Emergency Room Evaluation for Heart Failure Immediately Preceding and Following an Outpatient Transfusion Event in Hemodialysis, CKD-NOD and Non-CKD Medicare Patients Between 2003 and 2007. ........................................... 16 Figure 3. Adjusted Five-Year Survival Among Dialysis and Kidney Transplant Patients70 ................................................................................................. 18 Figure 4. Long-Term Survival of Patients Receiving a Kidney Transplant Before (Pre-Emptive) and After (Non Pre-Emptive) the Initiation of Dialysis 51............................................................................... 18 Figure 5. Unadjusted Graft Survival in 21,836 Recipients of Living Transplants by Length of Dialysis Treatment Before Transplant ............. 19 Figure 6. (a) Unadjusted Graft Survival in 56,587 Recipients of Cadaveric Transplants by Length of Dialysis Treatment Before Transplant (b) Unadjusted Graft Survival in 21,836 Recipients of Living Transplants by Length of Dialysis Treatment Before Transplant ............. 19 Figure 7. Effect of Transfusion on Graft Survival ........................................................... 23 Figure 8. Relationship Between the Number of Transfusions and the Risk of Allosensitization ....................................................................................... 25 Figure 9. (a) Long-term (10-year) graft survival of cadaver kidney transplants according to pre-transplant allo-sensitization (measured as PRA), and (b) 10-year follow-up of kidney grafts from HLAidentical sibling donors 61. ........................................................................ 26 MEDCAC Background Information Page 7 of 290 Page 5 Figure 10. Percent of Patients Receiving a Transfusion at Baseline and in Weeks 1-12 and 13-24 for Patients Randomized to Epoetin Alfa and Placebo Treatment 96. ................................................................ 29 Figure 11. Outpatient Transfusion Rate in US Dialysis Patients in Each Quarter Over Time. .................................................................................. 30 Figure 12. The proportion of US patients between 1991 and 2007 (a) who were transplanted and received previous transfusions, and (b) who had a PRA=0% while on the transplant wait list71. ........................... 31 Figure 13. Improvements in Exercise Tolerance and Physical Function Observed when Hemoglobin Levels were Increased with Epoetin Alfa Compared to Placebo-Treated Patients. ............................. 32 Figure 14. Summary of Studies Examining Changes in Exercise Tolerance (VO2peak) in Dialysis Patients following ESA treatment12 ........................ 33 Figure 15. Summary of Studies Examining Change in the Karnofsky Performance Scale (KPS) following ESA treatment ................................ 33 Figure 16. Improvements in Fatigue Observed when Hemoglobin Levels were Increased with Epoetin Alfa Compared to PlaceboTreated Patients 96, 102. ............................................................................. 34 Figure 17. Mortality rate and hemoglobin levels preceding and following the introduction of EPOGEN® ........................................................................ 35 Figure 18. Transfusion Risk by the Previous Month’s Hemoglobin Level in the Lower Hemoglobin Arm of the Normal Hematocrit Cardiac Trial (NHCT)............................................................................................. 36 Figure 19. Hemoglobin Levels and Transfusion Rates between 1991 and 2007 ......................................................................................................... 37 Figure 20. Transfusion Rates by Number of Months with an Outpatient Hemoglobin Below 10 g/dL and 11 g/dL; Medicare Hemodialysis Patients, 2004.................................................................... 37 Figure 21. The Prevalence of Significant Anemia (Hb < 10 g/dL) According to Level of Kidney Function (Estimated Glomerular Filtration Rate [eGFR]; Lower eGFR Indicates More Severe Disease) ........................... 43 Figure 22. Annual Transfusion Rates in CKD-NOD Patients in the Absence of ESA Therapy (2002-2007) ................................................................... 44 Figure 23. Hemoglobin Levels and Associated Kidney Disease Questionnaire (KDQ) Scores for Physical Symptoms, Fatigue, Depression, Relationship with Others, Frustration, and Overall KDQ (Clinically Meaningful Change in KDQ is 0.5) 108, 139, 143, 144 . ............................................................................................................ 46 MEDCAC Background Information Page 8 of 290 Page 6 List of Abbreviations Abbreviation or Term Definition/Explanation AABB American Association of Blood Banks AMR Antibody Mediated Rejection CESG Canadian Erythropoiesis Study Group CKD Chronic Kidney Disease CMS Centers for Medicare & Medicaid Services CRDAC Cardiovascular and Renal Drugs Advisory Committee CV Cardiovascular DAC (FDA) Drug Advisory Committee DSA Donor-Specific Antigen EMP Erythropoietin Monitoring Policy (National Claims Monitoring Policy for ESAs in Hemodialysis Patients) ESA Erythropoiesis-Stimulating Agent ESRD End Stage Renal Disease Hb Hemoglobin HLA Human Leukocyte Antigens KDQ Kidney Disease Questionnaire MEDCAC Medicare Evidence Development and Coverage Advisory Committee NHCT Normal Hematocrit Cardiac Trial NOD CKD-Not On Dialysis PPS Prospective Payment System PRA Panel Reactive Antibody PRCA Pure Red Cell Aplasia PRO Patient Reported Outcomes QIP Quality Incentive Program RBC Red Blood Cells RCT Randomized Controlled Trial SD Standard Deviation SIP Sickness Impact Profile USPI United States Prescribing Information USRDS United States Renal Data System VA Veteran’s Administration MEDCAC Background Information 1. Page 9 of 290 Page 7 EXECUTIVE SUMMARY Amgen has prepared this document in response to the Medicare Evidence Development and Coverage Advisory Committee (MEDCAC) meeting scheduled by the Centers for Medicare & Medicaid Services (CMS) to review the currently available evidence regarding the effects of Erythropoiesis Stimulating Agents (ESAs) on health outcomes in adult patients with chronic kidney disease (CKD). In particular, CMS has asked the panel to review the available evidence on the impact of ESAs on renal transplant graft survival in patients who have CKD (pre-dialysis and dialysis) and anemia. Patients with CKD requiring dialysis are distinct from those who do not require dialysis (referred to as CKD-NOD patients) in that dialysis patients have significantly greater comorbidity, are hospitalized more frequently, have higher mortality rates, and require more intensive clinical management. Additionally, the prevalence and severity of anemia, due to insufficient production of erythropoietin by the kidney, is greater in dialysis patients, and is compounded by the substantial blood loss associated with the dialysis procedure. Anemia symptoms, which include fatigue, decreased energy, reduced physical function, weakness, and cognitive impairment, can have a significant adverse impact on the lives of CKD patients. This document separately reviews the management of anemia in these two distinct populations, with a focus on the risks of transfusions on transplant access and viability, and the appropriate use of ESAs to manage anemia in order to reduce transfusions and improve anemia symptoms. Anemia Management in CKD Patients on Dialysis The severity of anemia in dialysis patients necessitates therapeutic intervention. Prior to the development of ESAs, the primary treatment for anemia was RBC transfusions. RBC transfusions provide only transient elevations in hemoglobin and have intrinsic risks. ESAs have demonstrated effective management of anemia, thereby reducing the need for transfusions and improving physical function, exercise tolerance, and symptoms of anemia. Additionally, transfusions expose patients to numerous risks, such as blood-borne diseases, iron overload, and allosensitization. Allosensitization is a uniquely important transfusion-related risk for CKD patients as it can delay or preclude a kidney transplant and shorten kidney graft survival. As such, transfusions are not appropriate therapy for management of chronically anemic dialysis patients. Kidney transplant is the preferred treatment modality for CKD patients with end-stage renal disease (ESRD), as it removes the dependency on dialysis to sustain life. Patients with kidney transplants have superior overall survival, better quality of life, and lower MEDCAC Background Information Page 10 of 290 Page 8 health resource utilization and cost as compared to patients receiving dialysis. The earlier that a kidney transplant is performed, including prior to the initiation of dialysis, the better the overall patient and kidney graft survival. Allosensitization is the development of antibodies to foreign antigens, which can lead to an immunologic attack on a transplanted organ. Allosensitization can be measured by the panel reactive antibody (PRA) test, which reflects the percentage of the representative organ donor pool to which the potential recipient has alloantibodies (i.e., allosensitized). Higher PRA levels reflect greater levels of sensitization and fewer potential compatible organs. There are three principle ways in which patients can become allosensitized: 1) blood transfusion, 2) prior organ transplantation, and 3) pregnancy; of these, exposure to transfusions is the most readily modifiable factor. Studies suggest that the risk of allosensitization from RBC transfusions is cumulative, a particular concern for dialysis patients who are more likely to have been allosensitized by previous transfusions or failed kidney transplants. It has been estimated that prior to the availability of ESAs, patients on dialysis received, on average, 5-10 units of transfused blood annually. A large body of evidence shows that increasing PRA levels are associated with: 1) increasing wait time on the transplant waiting-list, 2) decreasing likelihood of finding a compatible organ, and 3) if a patient receives a transplant, shorter survival of the transplanted kidney. While many advances have been made in the field of transplantation and various strategies to reduce allosensitization have been and continue to be investigated, allosensitization persists as a key obstacle to transplantation. In recognition of this, transplant centers across the US recommend that patients on the transplant waiting-list avoid transfusions, if at all possible. The risks related to RBC products is recognized by the Circular of Information for the Use of Human Blood and Blood Components, which is published jointly by the American Association of Blood Banks (AABB), American Red Cross, America’s Blood Centers, and the Armed Services Blood Program, and states: “Red cell containing components should not be used to treat anemias that can be corrected with specific hematinic medications such as iron, vitamin B12, folic acid, or erythropoietin.” ESAs offer the clinically significant and unequivocal benefit of transfusion reduction, as well as improvements in physical function and exercise tolerance, in patients receiving dialysis. Transfusion avoidance protects against the acute risks of volume and MEDCAC Background Information Page 11 of 290 Page 9 potassium overload, the cumulative risks of iron overload, and exposure to viral and other infectious agents, as well as sensitization to foreign antigens The benefits of ESA therapy have been demonstrated in registrational trials and in over 20 years of clinical practice. Since their introduction into the dialysis population, ESAs have been an important therapeutic intervention for the effective management of anemia and have led to substantial reductions in transfusions and significant improvements in physical function, exercise tolerance, and anemia symptoms. Along with the decline in transfusions, exposure to transfusion-related risks has also markedly declined, as evidenced by the near-absence of iron overload and a doubling of the proportion of patients on the transplant waiting-list who are not currently allosensitized. These benefits were achieved with ESA therapy used to raise and maintain hemoglobin concentrations above 10 g/dL and within the range of approximately 10-12 g/dL. The totality of available evidence and the current FDA-approved label supports a Hb range of 10-12 g/dL for ESA therapy in dialysis patients, which reduces transfusions and improves physical function and exercise tolerance, while accommodating Hb variability and avoiding target Hb levels of ≥ 13 g/dl where risks have been observed. There are no new clinical data regarding the benefits of ESAs in dialysis to support changes in the recommended hemoglobin range of 10-12 g/dL. Anemia Management in CKD-NOD Patients While the prevalence of anemia is lower in CKD-NOD patients, anemia can be severe in some patients, particularly those nearing dialysis. Transfusions in these patients are not uncommon, and CKD-NOD patients who receive transfusions are vulnerable to the same risks as patients on dialysis, including the risk of allosensitization and its potential impact on transplant eligibility and graft survival. This is particularly relevant for CKDNOD patients nearing dialysis since up to 15% of all transplants are performed before dialysis initiation. ESAs are an important therapy for anemic CKD-NOD patients in whom transfusion avoidance is a meaningful clinical goal. Based on recently completed studies in CKD-NOD patients, Amgen has proposed label changes to limit the use of ESAs in CKD-NOD patients to those with significant anemia, who are at high risk for transfusion and in whom transfusion avoidance is clinically meaningful. At the end of this review there are four appendices which contain the following: Appendix A - CMS Questions and Amgen's Responses Appendix B - Select References MEDCAC Background Information Page 12 of 290 Page 10 Appendix C - Independent Review of the Clinical Literature Appendix D - Guidelines for Blood Transfusion 2. BACKGROUND AND INTRODUCTION The approval of the first recombinant erythropoiesis-stimulating agent (ESA), Epoetin alfa, in 1989 represented an important scientific breakthrough in medicine and revolutionized the care of patients with anemia of chronic kidney disease (CKD). The ability to produce erythropoietin (the hormone produced by the kidneys to stimulate red blood cell [RBC] formation) is impaired in CKD patients and this impairment is the primary cause of anemia in this disease. Amgen Inc. (Amgen) developed ESAs as therapies to stimulate RBC production in order to elevate and maintain hemoglobin (Hb) concentrations in patients with CKD and anemia, to avoid RBC transfusions and improve the symptoms of anemia. In the US, Epoetin alfa is approved and marketed under the trade names EPOGEN® by Amgen for the treatment of anemia in dialysis, and PROCRIT® by Centocor Ortho Biotech Inc. for the treatment of anemia in CKD not on dialysis (NOD). Darbepoetin alfa is marketed under the trade name Aranesp® by Amgen for both CKD-NOD and dialysis. EPOGEN® and Aranesp® are approved for the treatment of anemia associated with CKD, which includes patients receiving and not receiving dialysis. The Centers for Medicare & Medicaid Services (CMS) has called this meeting to discuss the evidence available regarding the effects of ESAs on health outcomes in adult CKD patients (pre-dialysis and dialysis). Specifically, CMS has asked the panel to review the available evidence on the impact of transfusion on renal (kidney) transplant graft survival in patients who have CKD with anemia. This briefing book discusses anemia in CKD in patients on and not on dialysis, and reviews the management of anemia in these two distinct populations, with a focus on the risks of transfusions on transplant access and viability, and the appropriate use of ESAs to manage anemia in order to decrease transfusions and improve anemia symptoms. 2.1 Patients with CKD Requiring Dialysis Differ Substantially From Patients Who Do Not Require Dialysis Patients with CKD requiring dialysis are distinct from those patients who do not require dialysis (referred to as CKD-NOD patients) in that dialysis patients have significantly greater co-morbidity, are hospitalized more frequently, have higher mortality rates, and require more intensive clinical management 1. Importantly, these populations also differ in the prevalence and severity of anemia 1. Anemia is severe and almost universal in patients receiving dialysis, due to their lack of renal mass and relative erythropoietin MEDCAC Background Information Page 13 of 290 Page 11 insufficiency for their level of anemia 2, 3. Compounding the anemia, patients receiving dialysis are subject to continuous blood loss from the dialysis procedure 4. In dialysis patients, if left untreated or undertreated, anemia can be severe and have a significant effect on patients’ lives with symptoms including decreases in physical functioning, lower energy, and cognitive impairment. In contrast, the CKD-NOD patient population is heterogeneous with respect to the degree of impairment of kidney function, presence of co-morbidities and severity of anemia. The prevalence of significant anemia (Hb < 10 g/dL) is relatively low in patients with early stage renal disease, but increases to approximately 20-30% in the subset of patients approaching dialysis 5, and is more common among women and ethnic minorities, especially African Americans 6. In the subset of CKD NOD patients with advanced kidney disease and significant anemia, patients may be symptomatic and treatment of anemia may be warranted. 3. ANEMIA IN DIALYSIS PATIENTS 3.1 Anemia is Severe, Nearly Universal, Highly Symptomatic and Associated with Significantly Decreased Physical Functioning, Exercise Tolerance and Health Related Quality of Life in Dialysis Patients Dialysis patients experience severe anemia almost universally 2. In the 1980s, before the development of ESAs, a typical dialysis patient had a mean Hb of approximately 7 g/dL 7, and often required chronic transfusions to maintain Hb concentrations at this level. For reference, healthy adults have, on average, Hb concentrations in the range of 13-17 g/dL in men and 12-16 g/dL in women 8. In addition, there are sub-groups within the dialysis population in whom anemia is more common and more severe (e.g., African Americans) 6, 9. The severity of anemia in dialysis patients is largely driven by the relative deficiency of endogenous erythropoietin production, and is compounded by the blood loss during each dialysis procedure along with a shortened RBC survival time 4. Dialysis patients lose blood by way of the dialysis procedure itself, require frequent blood sampling to monitor laboratory parameters, have an increased tendency for bleeding attributable to anticoagulation therapy administered during dialysis,4 and have an increased risk of gastrointestinal bleeding and re-bleeding, all of which contribute to substantial and ongoing blood loss 10, 11. In total, blood loss is estimated to be between 2.5 and 5.1 L (510 Units) of blood annually per hemodialysis patient 4, roughly equivalent to the circulating blood volume in a healthy adult. MEDCAC Background Information Page 14 of 290 Page 12 Anemia is associated with lethargy, weakness, shortness of breath, decreased physical functioning and decreased exercise tolerance 12. These symptoms contribute to a poor quality of life, and decreased productivity. 3.2 Severe Anemia Requires Therapeutic Intervention to Alleviate the Substantial Symptoms The severity of anemia in dialysis patients often necessitates therapeutic intervention. In the 1980s, before the development of ESAs, the available treatment options for anemia were limited to RBC transfusions, and to a smaller extent, androgen and iron therapy 2. Androgens and iron therapy conferred only modest efficacy but had substantial side effects 13, 14, leaving RBC transfusions as the mainstay of anemia therapy in the pre-ESA era. There are two approaches to the treatment of anemia: replacing blood through transfusion of RBCs or stimulating RBC production, which can be accomplished through correction of deficiencies such as iron, vitamin B12 or erythropoietin. Administration of ESAs is used to treat the anemia of CKD, which is primarily caused by inadequate production of erythropoietin because of damage to the kidney. Transfusions and ESAs are distinct in their efficacy, characteristics and clinical profile, and they are not interchangeable. Amgen is unaware of any RCTs which have evaluated the efficacy or quality of life of transfusions as a randomized treatment compared to ESA therapy, for the treatment of anemia in CKD patients. Today, nearly all dialysis patients who require chronic anemia therapy receive ESAs and intravenous iron to support erythropoiesis. Also, as there is a time lag between ESA administration and Hb response 15, ESAs are unsuitable as the sole therapy for anemia requiring urgent treatment. Therefore, transfusions are generally reserved for acute situations requiring immediate anemia treatment, whereas ESAs are more appropriate for routine maintenance of Hb. 3.3 Transfusions Are Only Transiently Effective In Dialysis Patients Who Are Chronically Unable To Produce Sufficient Red Blood Cells, And Transfusions Carry A Range Of Acute And Chronic Risks Transfusions are transiently effective and insufficient for maintaining elevated Hb concentrations to alleviate the symptoms of anemia in the chronically anemic dialysis patient 16. Figure 1 depicts a typical pattern of transient improvement in Hb concentrations following transfusion in a dialysis patient, as well as the consequent reliance upon repeated transfusions to elevate Hb concentrations 16. The placebo arm of the Canadian Erythropoiesis Study Group (CESG) study 7 is illustrative of the limitations of the transient nature of transfusion therapy for the Page 15 of 290 MEDCAC Background Information Page 13 management of anemia in dialysis patients. The placebo arm employed usual care, including transfusions guided by normal medical practice. The resulting achieved Hb concentration was between 7-8 g/dL in the placebo arms of this and other trials; in contrast, the ESA arms of the CESG study had Hb concentrations between 10 and 12 g/dL. There was a demonstrable improvement in measurements of exercise tolerance, physical functioning and other domains of Quality of Life in the ESA treated groups compared to the group treated with placebo with normal transfusion practice. Figure 1. Pattern of Transient Improvements in Hb Concentrations Following Transfusions in a Dialysis Patient 45 14 Hct (%) 10 25 8 6 15 5 ↑ ↑ ↑ ↑ ↑ ↑ ↑ Hb (g/dL) 12 35 4 Transfusions 4 8 12 16 Weeks Furthermore, blood transfusions also constitute an additional burden for dialysis patients, both from a time and resource perspective. Before a blood transfusion can be infused, a blood sample is drawn to match with the blood intended for the transfusion. A transfusion generally requires several hours to complete. Currently, most dialysis centers do not have the capability of administering transfusions, thereby requiring the patient to visit an outpatient transfusion center, or be referred for hospitalization. Transfusions performed in non-dialysis outpatient infusion clinics necessitate venous access and as such increase the possibility that patients’ large veins may be compromised, thereby impairing opportunities for dialysis fistulas. This is a significant issue as dialysis vascular access complications are the most common cause for hospitalization 17. Lastly, while serious transfusion reactions are rare, non-hemolytic febrile reactions may still occur and produce symptoms that negatively impact patients. MEDCAC Background Information 3.3.1 Page 16 of 290 Page 14 Transfusions Are Recognized As Having Intrinsic Risks Prior to the availability of ESAs, transfusions were chronically administered but used with restraint given their known risks. These risks include transmission of blood-borne diseases, transfusion reactions, acute volume and potassium overload, and more chronically, iron overload and sensitization to foreign antigens 2, 18-21. Management of many of these complications may require hospitalization, which can further add to the risks, burden, and costs of transfusions 22, 23. Almost all US states have laws recognizing transfused blood as intrinsically hazardous 24 . The FDA also recognizes that the risks of blood transfusions can never be eliminated: “FDA is responsible for ensuring the safety of the Nation's blood supply. While a blood supply with zero risk of transmitting infectious disease may not be possible, there are several measures taken by FDA to protect and enhance the safety of blood products” 25. The Circular of Information for the Use of Human Blood and Blood Components is prepared jointly by American Association of Blood Banks (AABB), the American Red Cross, America’s Blood Centers, and the Armed Services Blood Program 26,and the Food and Drug Administration (FDA) recognizes this Circular of Information as an acceptable extension of container labels. This document provides under the contraindication section the following statement: Red-cell-containing components should not be used to treat anemias that can be corrected with specific hematinic medications such as iron, vitamin B12, folic acid, or erythropoietin. RBCs or Whole Blood should not be used solely for volume expansion or to increase oncotic pressure of circulating blood. Thus, even with the substantial improvements in blood safety, transfusions of blood products are recognized as intrinsically dangerous, and thus are not to be used when alternatives are available. 3.3.2 Transfusions Can Transmit Infectious Diseases Over the past 20 years, the blood supply has become safer with regard to transmission of infectious diseases including hepatitis B, hepatitis C, HIV, and other infections, due to the implementation of sensitive donor-screening strategies. Nonetheless, blood-borne pathogens including viral, protozoan, and parasitic diseases can still be transmitted by transfusion 27, 28,18. Known and emerging blood-borne pathogens are a significant concern in the blood supply. The AABB’s Transfusion Transmitted Diseases Committee recently conducted a MEDCAC Background Information Page 17 of 290 Page 15 review to identify actual or potential risks of current transfusion transmission. Sixty-eight infectious agents were identified, and with few exceptions, these agents did not have available interventions to reduce the risk of transmission 29. These agents and diseases include Creutzfeldt-Jakob disease, Dengue viruses, Babesia, Cytomegliovirus (CMV), HGV, malaria, leishmaniasis, Lyme disease, Human Herpesvirus 8 (HHV-8), toxoplasmosis, and cryoglobulinemia 30. More recently, Xenotropic Murine Leukemia Virus-Related Virus (XMRV), a virus linked to chronic fatigue syndrome, has been identified as a possible agent which could be transmitted via blood transfusion. In 2010, the AABB issued a recommendation that until further definitive data are available its member blood collectors should discourage potential donors diagnosed with chronic fatigue syndrome from blood donation 31. The effectiveness of these efforts is unknown. Usually interventions are not implemented until it is clear that transfusion transmission has occurred. Consequently, transfusions continue to expose patients to the risk of blood-borne diseases, some known, some emerging, and, some as yet unidentified. 3.3.3 Transfusions Can Cause Volume Overload, Hyperkalemia, Transfusion Reactions, And Transfusion-Related Acute Lung Injury (TRALI) In contrast to the general population, CKD patients have a diminished ability to excrete fluid and electrolytes due to their impaired renal function 32, and thus are particularly vulnerable to volume overload (heart failure exacerbation) and hyperkalemia 18-21. These particular risks related to transfusions in CKD patients were identified over three decades ago32. The frequency and impact of these transfusion-related risks were examined in a recent analysis of US Medicare data; this analysis showed that in the days immediately following an outpatient transfusion event, hospitalization or emergency room visits with a diagnosis for heart failure occurred at a rate 4- to 7-fold higher than in the days immediately preceding the transfusion event 33 (Figure 2). Similar results were observed for hospitalizations for hyperkalemia. Thus, the CKD population demonstrates particular susceptibilities to blood transfusion that may not be present in the general population. Page 18 of 290 MEDCAC Background Information Page 16 Heart Failure Rate per 100,000 Transfusions Figure 2. Rate of Hospitalization or Emergency Room Evaluation for Heart Failure Immediately Preceding and Following an Outpatient Transfusion Event in Hemodialysis, CKD-NOD and Non-CKD Medicare Patients Between 2003 and 2007. 800 600 CKD 400 200 HD Non-CKD 0 Day Prior Day After Day 2 Day 3 Day 4 CKD = CKD-NOD, HD = Dialysis Additional acute but rare consequences of transfusions include transfusion reactions and TRALI, the latter of which can be severe or fatal 34. 3.3.4 Transfusions Can Cause Iron Overload Iron overload can occur in transfusion-dependent patients since each unit of RBCs contains approximately 200-250 mg of iron, which is ~100 times greater than what is absorbed through daily dietary absorption in healthy adults 35. The body’s ability to excrete iron is extremely limited and excess iron accumulates in several organs including liver, spleen, heart, and vasculature. Iron accumulation in tissues can be detected, quantified, and localized via magnetic resonance imaging (MRI) of affected organs 35. The accumulation of iron in the tissues can cause damage or failure of multiple organs 35, liver cirrhosis with its associated risk of hepatocellular carcinoma, diabetes mellitus, and cardiac failure 36. In dialysis patients, studies performed before the introduction of ESAs also suggest that iron overload may increase a patients’ susceptibility to bacterial infections 37-39. The risks of iron overload are well-described in the literature and were known as early as the mid 1970s32, 40-43. Iron overload can occur after approximately 20 units of transfused blood 44. To contextualize this burden of transfusions, prior to the availability of ESAs, transfused dialysis patients were reported to have received approximately 5-10 transfusions a year 7. The frequency of iron overload in the CKD population has decreased since the introduction of ESAs and the consequent reduction in the use of transfusions 14. MEDCAC Background Information Page 19 of 290 Page 17 However, even today, chronic transfusion therapy for the treatment of anemia can still result in iron overload. Iron overload is a significant clinical problem in other diseases that require chronic transfusion therapy, such as myelodysplastic syndrome (MDS), sickle cell anemia, and thalassemia major. In these patients, transfusion-related iron is associated with substantial morbidity and mortality 45-48. Given these findings and the data from the pre-ESA era, the evidence suggests that iron overload would once again be a significant problem if transfusions become more prevalent. 3.3.5 Transfusions Can Result In Sensitization, Which Compromises Transplant Eligibility And Graft Survival For CKD patients, potentially the most important transfusion-related risk is the development of sensitization to foreign antigens, which can increase time spent on the transplant waiting-list or even preclude transplant eligibility, and for patients who receive a transplant, can shorten graft survival 49. 3.3.5.1 Transplant Is The Preferred Treatment Strategy For End-Stage Renal Disease: Delayed Transplantation Decreases Both Patient And Graft Survival Kidney transplant is the preferred CKD treatment modality as it removes the dependency on dialysis to sustain life, and effectively replaces kidney function in most cases. Patients with kidney transplants have superior overall survival (Figure 3), better quality of life, and have significantly lower health resource utilization and cost as compared to patients receiving dialysis50. Delays in transplantation decrease both patient and allograft survival. As compared to patients who receive a transplant following initiation of dialysis, patients who receive a transplant prior to initiating dialysis (pre-emptive transplant) have a 52% reduction in the risk of allograft failure during the first year after transplant (p = 0.002) and a more than 80% reduction yearly 51. Similarly, a study examining the fate of paired donor kidneys (i.e., two kidneys from the same deceased donor) demonstrated a decreased 10-year graft survival of kidneys transplanted into patients who had received 24 months of dialysis as compared to patients who had received 0-6 months of dialysis prior to transplant (Figure 4) 52. These authors also reported a similar relationship between duration of dialysis and overall graft survival for both cadaveric and living donor transplants (Figures 5 and 6). Because the length of time on dialysis prejudices against both patient and graft survival, the preference is to perform the transplant as early as possible, including before the initiation of dialysis. Page 20 of 290 MEDCAC Background Information Page 18 Figure 3. Adjusted Five-Year Survival Among Dialysis and Kidney Transplant Patients70 Survival Probability 100 80 60 40 Dialysis 20 Transplant 0 1 2 3 4 5 Years Proportion of Allografts Surviving Figure 4. Long-Term Survival of Patients Receiving a Kidney Transplant Before (Pre-Emptive) and After (Non Pre-Emptive) the Initiation of Dialysis 51. 1.00 Preemptive 0.75 Nonpreemptive 0.50 0.00 No. at Risk Preemptive Nonpreemptive 0 365 730 1095 1460 Allograft Survival (days) 1819 6662 1778 6430 1336 4519 877 2543 271 786 Page 21 of 290 MEDCAC Background Information Page 19 Figure 5. Unadjusted Graft Survival in 21,836 Recipients of Living Transplants by Length of Dialysis Treatment Before Transplant 100 % event free survival 90 0–6 80 70 >2 60 4m on m on th s 50 78% th s on d ialy sis on 58% dia 63% lys is 40 29% 30 20 0 12 24 36 48 60 72 84 months post-transplant 96 108 120 Figure 6. (a) Unadjusted Graft Survival in 56,587 Recipients of Cadaveric Transplants by Length of Dialysis Treatment Before Transplant (b) Unadjusted Graft Survival in 21,836 Recipients of Living Transplants by Length of Dialysis Treatment Before Transplant b. 100 100 90 90 80 preemtive 70 60 50 0-6 months 40 6-12 months 12-24 months 24+ months 30 20 0 3.3.5.2 12 24 36 48 60 72 84 96 108 120 months post-transplant % event free survival % event free survival a. 80 preemtive 70 0-6 months 60 6-12 months 12-24 months 24+ months 50 40 30 20 0 12 24 36 48 60 72 84 96 108 120 months post-transplant Techniques In Characterizing Immunologic Impediments To Successful Transplantation With the exception of transplants between identical twins, transplantation poses the risk of immunological attack on the transplanted organ that may lead to immediate, shortterm, or long-term loss of the transplant through both cell-mediated and antibodymediated rejection 53. Given that the presence of recipient antibodies directed against donor organs negatively affects the outcome of transplantation 54, antibody mediated rejection is the focus of discussion in this document. MEDCAC Background Information Page 22 of 290 Page 20 There are specific immunological tests that are traditionally performed prior to transplantation: ABO blood type testing, Human Leukocyte Antigen (HLA) typing, and Panel Reactive Antibody (PRA) evaluation. Transplants are generally not performed across ABO blood type boundaries, although there are some experimental approaches to transplantation across this barrier 55. Greater degrees of HLA mismatching generally correlate with worse transplant outcomes and affect waiting list priority for organ allocation 56. However, even in the presence of high degrees of HLA type mismatch, renal transplants may proceed, and thus HLA matching is not determinative. The PRA test has traditionally been used to inform the likelihood of a positive crossmatch and to appropriately manage organ allocation, and is described in greater detail in subsequent sections. Patients with elevated PRA are considered to be sensitized and sensitized patients may experience: • Increased wait time for a suitable donor kidney • Inability to ever find a suitable donor kidney • Greater chance of both acute rejection and of long-term organ loss The importance of the PRA and HLA matching notwithstanding, the ultimate test that determines whether a transplant for an individual candidate can proceed is the crossmatch test. The crossmatch, which is performed between the potential recipient and the donor cells at the time of transplant, is a specific determination of whether the kidney transplant recipient has antibodies directed towards the specific donor’s cells. If the crossmatch test is positive at time of transplant, there is a very high probability of acute antibody mediated rejection57 and will generally preclude transplant of the organ (other than in special and investigational circumstances). Thus, the presence of a negative crossmatch is the determining factor in deciding whether to perform a transplant between a donor and recipient pair. A more detailed discussion of crossmatching is provided in Section 3.3.5.4. MEDCAC Background Information Page 23 of 290 Page 21 It is important to note that even in the presence of a negative crossmatch, recipients with a high PRA, indicating the presence of broad allosensitization, are at greater risk for early acute antibody-mediated rejection and have worse short- and long-term outcomes 58, 59. The precise mechanism for this is unknown, but is hypothesized to be related to both low-level pre-existing antibodies that are not detected by crossmatch, the occurrence of post-transplant sensitization 60, and the possibility that non-HLA directed antibodies may promote late graft loss 61. Historical Development of Immunological Matching Techniques In 1964, Terasaki, et al demonstrated that the presence of recipient antibodies directed toward organ donor tissue strongly predicted immediate transplant failure 57. This finding was the basis of the pre-transplant crossmatch test, which is still used today. When a potential donor organ is identified, the prospective recipient’s serum is mixed with the donor’s cells to determine if the recipient has antibodies against the donor tissue. If a recipient has antibodies which react against the donor cells, known as a positive crossmatch, the probability of rejection is high, and the transplant will generally not proceed. The performance of the crossmatch remains the gold standard of organ compatibility. In a seminal advancement in 1969, Patel and Terasaki demonstrated that when a patient’s serum contained antibodies to a broad range of donor cells, randomly derived from different individuals in the general population, the patient had a much higher probability of experiencing acute organ rejection following transplantation 62. This was the basis for the panel reactive antibody test, which measures a patient’s level of sensitization to a representative pool of donor HLA antigens. The PRA, expressed as a percentage, reflects the percentage of the likely organ donor pool for which the potential recipient has alloantibodies (is allosensitized). For example, a PRA of 70% suggests that 70% of donors will likely be unacceptable for the tested patient due to the presence of anti-HLA antibodies against donor antigens. Thus, the higher the percent PRA, the more ‘allosensitized’ a patient is to the general donor pool, and the more difficult to find a suitable donor. Allosensitization is often categorized as a PRA of 0%, indicating no sensitization; <10% or < 20%, indicating a low level of sensitization; < 79% indicating a moderate degree of sensitization; and ≥ 80% indicating a high-degree of sensitization. MEDCAC Background Information Page 24 of 290 Page 22 Evolving Techniques in Determining Allosensitization While the role of antibodies in hyper-acute rejection has been known for decades 57, it was not until the introduction of specific and sensitive anti-HLA antibody testing techniques that the role of antibody-mediated rejection in short and long-term graft outcome was fully recognized 54, 63, 64. In recent years, solid phase assays have been introduced that improve upon the cell-based assays for HLA antibody screening and have refined our understanding of sensitization 63, 65. These assays are more sensitive than previous methods in detecting HLA antibodies, and fall into two categories, ELISAbased and HLA antigen-coated beads used in either a Flow Cytometry system or a Luminex platform. The Luminex platform-based assay is now the standard methodology for assessing sensitization and determining organ allocation in the US 63. These tests allow the determination of a calculated PRA (cPRA). The cPRA is based upon HLA antigens to which the patient has been sensitized and which, if present in a donor kidney, would represent an unacceptable risk of rejection; these are referred to as unacceptable antigens. The cPRA is computed from HLA antigen frequencies among approximately 12,000 kidney donors in the United States between 2003 and 2005 and thus represents the percentage of actual organ donors that express one or more of those unacceptable HLA antigens 64. Since 2009, transplant waiting list patients’ cPRA and their specific unacceptable antigens are required to be reported to UNOS in an effort to increase the chances that an organ offered to a highly sensitized patient, who has likely spent considerable time on the transplant waiting list, will prove to be crossmatch negative. It is important to clarify what these newer tests accomplish: • They may more closely approximate the results of the pre-transplant cross-match • They improve the efficiency of organ allocation • They reduce the chances that a highly sensitized patient will be offered an organ that will be found to have a positive crossmatch It is also important to clarify what the newer tests do not accomplish: • They do not alter the likelihood that a suitable donor will be found • They do not alter the length of time required to find a donor • They do not alter the fact that highly sensitized patients may never find a suitable organ Page 25 of 290 MEDCAC Background Information • Page 23 They do not alter the fact that even if an organ is found, higher PRAs predict a higher risk of both acute rejection and long-term organ loss 3.3.5.3 The Role Of Transfusions In The Development Of Allosensitization There are three principle ways in which patients can become allosensitized: blood transfusion, a prior organ transplantation, and pregnancy 66, 67 . Of these, exposure to transfusions is the most readily modifiable factor. The role of transfusion in sensitization has been described since the 1960s, with the initial description of the PRA test 62. Analyses of the relationship between prior transfusions and transplant survival revealed that pre-transplant transfusions are detrimental to graft survival (Figure 7) 68. Figure 7. Effect of Transfusion on Graft Survival 100 100 Percent Graft Survival PRA 0–10% PRA >10% 90 90 80 70 60 80 Number of transfusions N 0 18,086 1–5 8,126 6–10 993 >10 577 0 1 Number of N transfusions 3,816 0 2,871 1–5 427 6–10 333 >10 70 2 3 60 0 1 2 3 Years Posttransplant Following the demonstration of the negative effects of transfusion on transplant outcome 68 , numerous studies have evaluated the impact of transfusions on the development of allosensitization 69, 70 and the impact of allosensitization on the time on transplant waiting-list, ability to receive a transplant, and transplant graft survival 3, 61, 71. Studies suggest that anti-HLA antibodies can be observed after one episode of transfusion 72, 73. In a study of over 600 non-sensitized female patients receiving a pretransplant transfusion, 21% became sensitized 69. Data from approximately 70,000 transplanted patients show that the patients who receive transfusions have higher risk of sensitization 3 and the risk of allosensitization from RBC transfusion is cumulative, as the number of previous transfusions increases, so does the risk of elevated PRA levels 74 (Figure 8a). The likelihood of sensitization following transfusion is greatest among multiparous females and previous transplant patients 3, 68, 71, 75. Each transfusion introduces the possibility of sensitization to more HLA-antigen subtypes, thereby reducing the pool of suitable donor organs for the patient 3, 68, 75. Importantly, since Page 26 of 290 MEDCAC Background Information Page 24 dialysis patients are more likely to have been allosensitized by previous transfusions 68, 69, 71 , or previous failed kidney transplants 67 , they are at particular risk for an increase in allosensitization following transfusion. Leukoreduction in Transfusions A proposed mitigation strategy to reduce the sensitizing effect of transfused blood is leukoreduction, a process that removes leukocytes from the donor blood prior to transfusion. In the oncology population, where patients receiving chemotherapy also receive multiple transfusions, the development of HLA-antibodies may reduce the effectiveness of platelet transfusions. Leukoreduction of transfused platelets has been shown to successfully reduce the relative risk of developing anti-platelet antibodies by approximately 50% 76, thereby increasing the effectiveness of platelet transfusions. However, transfusing leukoreduced blood has not been shown to mitigate the risk of developing HLA antibodies in the context of renal transplantation 53, 77. Karpinski, et al 78 have shown that after a Canadian province uniformly adopted leukoreduction, there was no decrease in the level of allosensitization following RBC transfusion among kidney transplant candidates. Consequently, the authors concluded: “...transfusions continue to be an important cause of allosensitization for potential kidney transplant recipients.” The precise reason for the differential impact of leukocyte reduction in reducing allosensitization associated with transfusions in the oncology setting, but not in the renal setting, is not clear. One hypothesis that has been proposed is that there is a difference in the level of immune suppression in patients with cancer receiving chemotherapy (as in the TRAP study76) in comparison to transplant-eligible CKD patients 53. Additionally, studies in the surgical setting have shown that HLA sensitization persists after transfusion of leukoreduced blood 79, 80. 3.3.5.4 Impact Of Transfusions And Allosensitization On Transplant Opportunities And Outcomes The relationship between PRA levels and transplant outcomes has been extensively described in large population studies and in review articles and textbooks of transplantation medicine 3, 61, 68. The presence and degree of allosensitization can adversely impact transplant outcomes in multiple ways, including the availability of fewer suitable organs, increased wait time for transplant, inability to receive a transplant, and shortened graft survival over the short and long term 3, 61, 68. USRDS data indicate that moderately to highly sensitized patients have the longest median wait times for a kidney transplant (Figure 8b), and the longer wait times are Page 27 of 290 MEDCAC Background Information Page 25 associated with greater likelihood of death (Figure 8c). For patients who are highly sensitized (PRA > 80%), there is no median time to transplant as the majority are never transplanted 81. This is even more pronounced among African Americans who have a higher likelihood of being sensitized by transfusions and a lower probability of finding a suitable matching organ 71, 74. Figure 8. Relationship Between the Number of Transfusions and the Risk of Allosensitization (a) ref 10 Number of Previous Transfusions (c) PRA Likelihood of dying while awaiting transplant 8 6 Probability Median Wait Time in Years Odds Ratio Relationship between transfusion and PRA (b) 4 2 Years of Listing Years of Listing (a) Relationship between the number of transfusions and the risk of allosensitization (measured as panel reactive antibody [PRA] > 50%; PRA measures anti-human antibodies in the blood) (b) The median time spent on the transplant waiting-list by the level of allosensitization (measured as PRA < 10% versus > 10%) (c) The likelihood of dying while waiting for transplant 50, 74. The longer a patient remains on the transplant waiting-list, the higher the likelihood the patient will receive additional transfusions, further exposing the patient to the risk of increasing levels of sensitization. Recent estimates suggest that more than 30% of patients on the transplant waiting list receive one or more blood transfusions within 3 years of being listed 71. A recent analysis of USRDS data suggests that blood transfusion is associated with a 28% reduction in the likelihood of receiving a transplant in up to 8 years of follow up 71. This is important as the longer a patient is on a transplant waiting list the higher the likelihood the patient will die prior to receiving a transplant (Figure 8c). Additionally, as discussed previously, kidney allograft survival has been shown to be substantially shorter the longer a patient remains on dialysis before transplantation 51. The disadvantages of long wait times have a significant impact on the lives of dialysis patients. A key concept regarding allosensitization in kidney transplantation is that once a suitable organ is found, (i.e., an organ with a negative crossmatch) the presence of pretransplant allosensitization can still compromise the overall function and longevity of the Page 28 of 290 MEDCAC Background Information Page 26 transplanted kidney 61, 82. A recent study of over 100,000 transplants showed that increasing levels of sensitization are associated with significantly shorter graft survival (3 years shorter on average for highly sensitized compared to non-sensitized patients) 68 (Figure 9a). Similar findings were also observed among HLA-identical sibling transplants (Figure 9b) 61, which is notable since there is a reduced intrinsic immunologic barrier to transplantation between HLA-identical siblings. This relationship is further supported by a recent study in nearly 70,000 kidney transplant recipients which shows that increasing levels of sensitization are associated with significantly higher risks of allograft failure and death 3. In addition to HLA antigens, there may be other non-HLA immunologic factors that explain these findings 61. The relationship between graft failure and higher levels of PRA as determined with older assays, has been shown in numerous studies to be consistent with data using the current solid phase techniques for detecting antibodies 82, 83. Figure 9. (a) Long-term (10-year) graft survival of cadaver kidney transplants according to pre-transplant allo-sensitization (measured as PRA), and (b) 10-year follow-up of kidney grafts from HLA-identical sibling donors 61. (b) 100 100 90 90 Grafts surviving (%) Grafts surviving (%) (a) 80 70 60 50 p<0·0001 No PRA 40 0 1–50% PRA >50% PRA 0 2 4 6 Time (years) 8 10 Number of transplants 116562 83720 62516 44887 30819 20674 No PRA 1–50% PRA 36314 25005 18402 12842 8590 5586 >50% PRA 7610 4712 3582 2579 1817 1242 80 No PRA 70 1–50% PRA 60 p<0·0001 >50% PRA 50 40 0 0 2 4 6 8 Time (years) Number of transplants No PRA 3001 2495 1929 1418 1–50% PRA 803 647 514 362 >50% PRA 244 192 149 111 989 249 84 10 687 158 65 Of the three ways in which allosensitization occurs, transfusions are the most easily avoided. Thus, the principle of transfusion avoidance is widely accepted and is integrated into pre-transplant management protocols at most transplant centers (Appendix B). MEDCAC Background Information 3.3.5.5 Page 29 of 290 Page 27 Donor-Specific Transfusions And Transplant Outcomes Among Living Donor Kidney Transplants Donor-specific transfusions (DSTs) were proposed as a method of inducing immune tolerance based on experimental considerations 84, and first reported as potentially beneficial by Salvatierra in 1980 85. DSTs are a therapy consisting of transfusions of 13 units of blood from the donor who is offering the kidney. These transfusions are administered to the recipient prior to the kidney transplant, with the intent of inducing immune tolerance to the donor kidney and improving the long-term kidney allograft survival 85. DSTs, which can only be employed in the context of living donor kidneys, are distinctly different from therapeutic transfusions used for the treatment of anemia; therapeutic blood transfusions expose the recipient to blood from many unselected donors for the purpose of treating anemia. For context, in the pre-ESA era, dialysis patients received on average 5-10 units of transfused blood annually, and in the process may have been exposed to the blood of a large number of donors in the course of receiving multiple therapeutic transfusions 7. There is evidence supporting superior graft survival among living donor transplants in which DSTs were employed 86-90. However, it has also been reported that contrary to the intended purpose of inducing tolerance, up to 30% of prospective transplant recipients administered DSTs develop antibodies to the donor organ, thus precluding the organ transplant 91. While the patients who are allosensitized by DSTs remain eligible for other donor transplantation, living or deceased, the sensitization induced by the DST can compromise subsequent outcomes. Because of uncertainty about whether a DST will induce tolerance and improve graft outcomes, or induce sensitization which can preclude a living donor transplant and reduce the transplant options for the patient, DST is no longer widely advised 69, 92, and has been abandoned by most transplant centers 53. 3.3.5.6 Management Of Patients With High Levels Of Donor-Specific Antibodies For many highly allosensitized transplant candidates, an acceptable donor is never identified and the patient remains on dialysis indefinitely 55. In an attempt to offer the possibility of a transplant, protocols are being developed to permit transplants in highly sensitized patients with a positive crossmatch against a prospective living donor kidney 55. These protocols aim to acutely lower donor-specific antigen (DSA) activity to below the level that causes immediate renal allograft injury, and to maintain this reduced level during the first weeks to months after transplantation. The most commonly used of these experimental approaches involves the use of pre- and post-transplant MEDCAC Background Information Page 30 of 290 Page 28 immunosuppression, including intravenous immunoglobulin, with or without plasmapheresis, or the use of anti-CD20 monoclonal antibodies 93. However, these approaches are resource intensive 94, do not eliminate the risk of sensitization, are not FDA approved for this indication, and some are still considered experimental. A number of newer immunological reagents are under investigation for this application 55. With the exception of intravenous immunoglobulin (IVIG), desensitization protocols remain an experimental approach and do not reduce donor specific antibodies to a level allowing transplantation in all patients. Among patients whose antibody levels have been reduced sufficiently to allow a transplant to be performed, acute antibodymediated rejection (AMR) still occurs in 20 to 50% of transplants despite desensitization 55. Thus high levels of sensitization continue to persist as a key obstacle to transplantation 82. 3.4 ESA Therapy Reduces The Need For Recurrent RBC Transfusions And Their Attendant Risks By Effectively Raising And Maintaining Hemoglobin Concentrations And Improving Physical Function, Exercise Tolerance And The Symptoms Of Anemia Given the substantial risks associated with transfusions, the approval of ESAs markedly improved the management of anemia in CKD patients receiving dialysis. ESAs are approved for raising and maintaining Hb concentrations and reducing the need for transfusions. The Epoetin alfa label95 also describes improvements in physical functioning and exercise tolerance, and the literature supports other findings regarding the improvement in symptoms of anemia with ESA therapy. The replacement of chronic transfusions with ESA therapy aligns with recent recommendations on the use of RBC components by the AABB and the American Red Cross which state26: “Red-cell-containing components should not be used to treat anemias that can be corrected with specific hematinic medications such as iron, vitamin B12, folic acid, or erythropoietin.” 3.4.1 ESA therapy reduces the need for transfusions when used to raise Hb ≥ 10 g/dL and maintain it between 10-12 g/dL The primary registration trials used for the approval of Epoetin alfa demonstrated improvement of anemia and the virtual elimination of transfusions (> 90% reduction) in patients treated with ESAs to a hematocrit target of 35% ± 3% (Hb of 11.7 ± 1 g/dL) 96. While the Epoetin alfa treated patients became nearly transfusion independent, placebo treated patients remained severely anemic and continued to receive multiple transfusions. Once patients randomized to placebo were crossed over to receive Epoetin Page 31 of 290 MEDCAC Background Information Page 29 alfa, they experienced a reduction in transfusions similar to that seen in the patients initially randomized to Epoetin alfa treatment 96 (Figure 10). Figure 10. Percent of Patients Receiving a Transfusion at Baseline and in Weeks 1-12 and 13-24 for Patients Randomized to Epoetin Alfa and Placebo Treatment 96. 100% Percent (SE) of Subjects Receiving Transfusions 80% Placebo Epoetin alfa Placebo Δ Epoetin alfa 72% 58% 63% 60% Epoetin alfa from Week 13-24 40% 17%* 17% 20% 0% 0%* Baseline Weeks 1-12 Weeks 13-24 N = 32 (placebo); N = 36 (Epoetin alfa); *p < 0.05 placebo vs Epoetin alfa Baseline rates are based on the 6 months before the start of the study. Placebo Δ Epoetin alfa group: Transfusion requirements for subjects originally randomized to receive placebo in Study 8701 who began to receive Epoetin alfa after week 12. Almost immediately following the introduction of EPOGEN® into clinical practice in 1989, the outpatient transfusion rate among US hemodialysis patients fell sharply. This is shown in an analysis of USRDS data, which provides near-complete monitoring of all dialysis patients including medications, biochemical parameters, hospitalization events and deaths (Figure 11). Page 32 of 290 MEDCAC Background Information Page 30 Patients Transfused Per Quarter (%) Figure 11. Outpatient Transfusion Rate in US Dialysis Patients in Each Quarter Over Time. Use of ESAs Introduced 20 16 12 8 4 0 78 80 82 84 86 88 90 92 94 96 Year Footnote: Only pre-1996 outpatient transfusion data are represented as method for transfusion data collection changed after 1996. Adapted from USRDS ADR 2010 By 1992 almost 90% of US dialysis patients received ESA therapy and this treatment prevalence of > 90% continues today 97. Between 1991 and 2000, the mean population Hb increased from ~9.8 g/dL to ~11.2 g/dL and the total transfusion rate (inpatient plus outpatient) was significantly reduced 98. 3.4.2 ESAs Reduce The Frequency And Impact Of Transfusion Related Risks The availability of ESAs and the ability to raise Hb concentrations above 10 g/dL and maintain them within the range of approximately10 to 12 g/dL, has significantly reduced the frequency of transfusions, resulting in reduced patient exposure to transfusionrelated risks. For example, with regard to allosensitization, USRDS data show that between 1991 and 2008, the population mean Hb concentration increased, the proportion of transplanted patients who had a prior transfusion decreased from 49% to 15%, and the proportion of patients with no sensitization (PRA levels = 0%) increased from 24% to nearly 50% (Figures 12a and 12b). Page 33 of 290 MEDCAC Background Information Page 31 Figure 12. The proportion of US patients between 1991 and 2007 (a) who were transplanted and received previous transfusions, and (b) who had a PRA=0% while on the transplant wait list71. Pre-transplant transfusion 80.0 80.0 70.0 70.0 60.0 12.00 11.00 10.00 50.0 40.0 30.0 20.0 9.00 8.00 3.4.3 10.0 0.0 199 2 199 4 199 6 199 8 200 0 200 2 200 4 200 6 200 8 PRA = 0% Among Transplant Waitlist Patients 13.00 Mean Hb concentration Pre-transplant transfusion (%) Mean Hemoglobin (g/dL) 14.00 60.0 50.0 40.0 30.0 20.0 10.0 0.0 199 2 199 4 199 6 199 8 200 0 200 2 200 4 200 6 200 8 ESAs Improve Physical Function and Exercise Tolerance When Used to Raise Hb ≥ 10 g/dL and Maintain it Within the Approximate Range of 10-12 g/dL Statistically significant and clinically meaningful improvements in exercise tolerance and physical functioning were observed in registrational trials of dialysis patients receiving Epoetin alfa compared to placebo, and in numerous single arm and observational studies. In one registrational study, after 6 months of Epoetin alfa treatment, mean Hb increased from 7.1 g/dL to greater than 10 g/dL and improvements in exercise tolerance were demonstrated by objective measurements of time and distance walked using the modified Naughton Treadmill Test99, 100 and the six-minute walk test (Figure 13). In the same study, patient-reported physical functioning improved by approximately 61% using the Sickness Impact Profile (SIP) physical function scale, and 40% using the Kidney Disease Questionnaire (KDQ) Physical Symptoms domain 100. Page 34 of 290 MEDCAC Background Information Page 32 Figure 13. Improvements in Exercise Tolerance and Physical Function Observed when Hemoglobin Levels were Increased with Epoetin Alfa Compared to PlaceboTreated Patients. Minutes Walked Placebo (n = 40) Sickness Impact Profile (SIP) Physical Functioning Epoetin alfa (n = 78) Hb Level (g/dL) 7.2 7.1 7.0 10.7 7.4 11.0 7.4 11.0 17.0 16.9 17.2 15 10 11.9 13.4 12.8 12.7 13.2 5 0 Baseline 2 4 6 5.0 Mean (SE) Improvement From Baseline Minutes Walked 20 4.0 3.9 3.0 2.8 2.9 2.0 1.0 0.0 1.1 2 1.1 4 Months Months P < 0.001 placebo vs Epoetin alfa Epoetin alfa (n = 78) Placebo (n = 40) P < 0.001 placebo vs Epoetin alfa Additional evidence supporting the labeled PRO benefits of improvement in exercise tolerance and physical function comes from a recent systematic review and metaanalysis 12. Findings from this meta-analysis show a 23.8% increase in VO2peak (a measure of exercise tolerance) and 10.5% increase in Karnofsky Performance Score (functional outcomes) following initiation of erythropoietin therapy in dialysis patients (Figure 14; Figure 15). A more recent systematic review and meta-analysis of randomized controlled trial data related to the SF-36 short-form also found statistically significant improvement in physical function domains 101. 0.7 6 MEDCAC Background Information Page 35 of 290 Page 33 Figure 14. Summary of Studies Examining Changes in Exercise Tolerance (VO2peak) in Dialysis Patients following ESA treatment12 Box reflects mean change and whiskers represent 95% CI Figure 15. Summary of Studies Examining Change in the Karnofsky Performance Scale (KPS) following ESA treatment Box reflects mean change and whiskers represent 95% CI In addition to improvements in exercise tolerance and physical function which are described in the FDA-approved label, statistically significant and clinically meaningful improvements in other anemia symptoms including fatigue, depression, energy, and weakness were observed in registrational studies comparing Epoetin alfa to placebo. After 6 months of ESA treatment patient-reported fatigue improved by 24% (Figure 16), Page 36 of 290 MEDCAC Background Information Page 34 depression improved by 10.4 %, energy improved by 37.1%, and weakness improved by 55.9% when using the KDQ 96, 102. Figure 16. Improvements in Fatigue Observed when Hemoglobin Levels were Increased with Epoetin Alfa Compared to Placebo-Treated Patients 96, 102. % Improvement from Baseline Kidney Disease Questionairre (KDQ) Fatigue 30.0% Placebo (n=40) Epoetin alfa (n=78) 25.0% 20.0% 23.8% 21.4% 23.8% 15.0% 10.0% 5.0% 0.0% 4.4% 4.4% 2 4 Month 0.0% 6 P<0.0001 placebo versus Epoetin alfa (repeated measures mixed model) There were significantly greater improvements in energy in patients treated with Epoetin alfa compared to placebo, in a registrational RCT, as measured by the National Kidney Dialysis Kidney Transplantation Symptom Checklist (NKDKTS) Energy item (p = 0.006) and a single item Energy PRO (p < 0.001). A recent systematic review of patientreported fatigue demonstrated that raising Hb above 10 g/dL to within the 10-12 g/dL range yielded an average fatigue improvement of 29% 96. A recent meta-analysis of randomized control trial data related to the SF-36 also found statistically significant improvements in mental health and social function domains when Hb concentrations are raised and maintained in the 10-12 g/dL range using ESAs 101. Also measured by the SF-36, cognitive function has been found to be significantly improved by using ESA treatment 103. Statistically significant improvements were observed in patient-reported health status, with more than a 50% increase in the number of subjects rating their health as “Good” or “Excellent”, and more than a 30% increase in health satisfaction using the WHO QOL questionnaire, when average Hb concentrations increased to above 10 g/dL and were maintained to within the 10-12 g/dL range 104. Similar findings were observed in two additional randomized, placebo-controlled registrational studies, which showed MEDCAC Background Information Page 37 of 290 Page 35 statistically significant and clinically meaningful improvements in patient-reported health status 96. 3.4.4 ESAs Should be Considered in the Context of their Labeled Risks Safety considerations associated with ESAs have been discussed extensively at the September 2007 CRDAC meeting and at the October 2010 CRDAC meeting. Hypertension and thrombotic events are known adverse reactions of ESAs. Additional but rare risks include hypersensitivity reactions and pure red cell aplasia (PRCA). An increased risk of cardiovascular (CV) events and mortality was observed in clinical trials that used ESAs to target Hb concentrations ≥ 13 g/dL (above the labeled Hb range) 105107 . Based on the results of these trials, the United States Prescribing Information (USPI) 95 boxed warning describes that in clinical trials patients experienced greater risks for death, serious cardiovascular events, and stroke when administered ESAs to target Hb levels of 13 g/dL or above. In addition to clinical trial data, surveillance data on nearly all US hemodialysis patients is available through the United States Renal Data System (USRDS). These data show that since the introduction of ESAs into clinical practice where Hb levels are lower, the overall mortality rate in the dialysis population has not increased (Figure 17). Figure 17. Mortality rate and hemoglobin levels preceding and following the introduction of EPOGEN® Page 38 of 290 MEDCAC Background Information 3.4.5 Page 36 Substantial Evidence Supports the ESA Labeled Hemoglobin Range of 10-12 g/dL in Dialysis Patients There is a large body of data from registrational trials and 20 years of clinical experience regarding the use of ESAs and their clinical benefits in dialysis patients. This evidence is summarized in the following sections. 3.4.5.1 The Need for Transfusions Decreases Substantially when Hb Concentrations are Raised ≥ 10 g/dL and Maintained Within the Range of Approximately 10-12 g/dL with ESA Therapy Evidence from RCTs and general clinical practice strongly supports the need to raise and maintain Hb concentrations above 10 g/dL and within the range of 10-12 g/dL to reduce the need for transfusions 50, 96, 108. A post-hoc analysis of RCT data in the dialysis population calculating the likelihood (relative risk) of transfusion in the month following Hb measurement indicates that relative to a Hb of 10-11 g/dL, transfusion risk doubles if the Hb is between 9-10 g/dL and doubles again when the Hb is less than 9 g/dL (Figure 18)96. Figure 18. Transfusion Risk by the Previous Month’s Hemoglobin Level in the Lower Hemoglobin Arm of the Normal Hematocrit Cardiac Trial (NHCT) 8 7 6 The Risk of Transfusion by the Previous Month's Hemoglobin Level 5 Hazard Ratio (95% CI) 4 3 2.5 2 1.5 1.2 1 0.8 0.6 0.4 <9 9 - < 10 10 - < 11 11 - < 12 >=12 Hemoglobin level (g/dL) Data Source: NHCT study, data on file Likewise, in the clinical setting, the transfusion rate has declined substantially in the dialysis population as the proportion of patients with a Hb ≥ 10 g/dL has increased. A plateau was seen when the mean population Hb concentration reached 11.2 g/dL 71 (Figure 19). Page 39 of 290 MEDCAC Background Information Page 37 Figure 19. Hemoglobin Levels and Transfusion Rates between 1991 and 2007 Hb Transfusion 15.0 12.5 14.0 12.0 13.0 11.5 12.0 11.0 11.0 10.5 10.0 10.0 9.0 9.5 8.0 9.0 7.0 1991 1993 1995 1997 1999 2001 2003 2005 Proportion Transfused (%) Mean Hemoglobin (g/dL) 13.0 2007 The likelihood of transfusion also increases the longer the patient's Hb remains low 109. An analysis of approximately 160,000 Medicare hemodialysis patients shows that the transfusion rate increases substantially the longer Hb concentrations remain below 10 g/dL during consecutive months (Figure 20).110 These analyses emphasize the cumulative likelihood of transfusions when Hb concentrations remain below 10 g/dL. Figure 20. Transfusion Rates by Number of Months with an Outpatient Hemoglobin Below 10 g/dL and 11 g/dL; Medicare Hemodialysis Patients, 2004. Thus, the benefits in ESA therapy, when used to raise Hb concentrations above 10 g/dL to within the 10-12 g/dL range, have been demonstrated in numerous clinical trials and MEDCAC Background Information Page 40 of 290 Page 38 through surveillance of nearly the entire dialysis population (approximately 350,000 patients in 2008) 71. The importance of maintaining Hb concentrations above 10 g/dL and in the range of approximately 10-12 g/dL is recognized by the nephrology community, as well as CMS, and is currently incorporated as a quality metric by which dialysis units are evaluated. 3.4.5.2 A Two Gram Hb Range is Appropriate when Titrating ESA Doses to Maintain Hb Concentrations Above 10 g/dL Variations in Hb concentrations within individuals over time (intra-subject variability)111 are inherent. In dialysis patients, Hb variability is common and is further complicated by the frequent hospitalization events, inflammation, and other co-morbidities that patients experience, and the receipt of multiple interventions 111, 112. Additionally, there is a lag between ESA dosing and Hb changes.15 Therefore, it is extremely difficult to maintain Hb concentrations within a narrow range in most patients.111 In clinical practice, the population mean intra-patient Hb standard deviation (SD) is approximately 1.0 g/dL 113, therefore, at any given point in time a substantial fraction of patients will not be within a 2 g/dL range. Both the original registrational trials and the current FDA-approved ESA labels refer to a 2 g/dL Hb range of approximately 10-12 g/dL. This range is consistent with: i. the recognized need to maintain Hb levels above 10 g/dL to avoid transfusion ii. the inherent variability in patient Hb levels and the time lag between ESA administration and Hb response; and iii. avoidance of targeting Hb levels of ≥ 13 g/dL which has been associated with risk The influence of Hb variability on the management of anemia in dialysis patients is well recognized by CMS and has been incorporated into its National Claims Monitoring Policy for ESAs in hemodialysis patients (EMP) 114 . The EMP recognizes that in administering ESAs to achieve and maintain the Hb 10-12 g/dL Hb range, its reimbursement policy should account for this inherent variability 115. The importance of this range is further reinforced by the established Hb concentration levels used in the proposed Quality Incentive Program (QIP) under the Prospective Payment System (PPS) (10 and 12 g/dL) 116 . Thus, the Hb range of 10-12 g/dL enables physicians to effectively manage Hb concentrations with ESA therapy according to patient needs in order to avoid unnecessary RBC transfusions and improve physical function and exercise tolerance. MEDCAC Background Information 3.4.5.3 Page 41 of 290 Page 39 ESAs Have a Broad Dose-Response and There is no Evidence Supporting a Single Maximum Dose ESA therapy has been shown to be effective at raising and maintaining Hb concentrations across a wide range of doses. In the original EPOGEN® registrational program, phase II studies demonstrated a Hb response across all dosage levels 96. In the subsequent phase III studies, a 40-fold range in the dose was required to raise and maintain Hb concentrations within the target range of 10.7 to 12.7 g/dL 117. These results along with evidence from current practice highlight the marked variability in ESA doses required to raise and maintain Hb concentrations at a given level across individual patients. There is a wide range of doses needed to raise and maintain Hb concentrations within the CKD population, and the preponderance of available evidence does not support an increased risk of adverse events with higher doses. Initially, higher ESA doses were associated with increased CV and mortality risk 118, 119, however, it is now more widely understood that these observations were largely attributable to patient characteristics, worsening clinical status, and poor Hb response rather than ESA dose 120-122. Patients requiring the highest ESA doses are those most likely to have a greater CV disease burden, have more inflammation and malnutrition, be hospitalized more frequently, be poorly responsive to ESA therapy, and have low Hb levels 121, 123. The correlation of these prognostic factors with higher ESA doses can produce significant confounding 124. Numerous analyses using multiple, different analytical techniques to address the confounding have found that higher ESA dose is not associated with an increased risk of mortality 120, 124-127. 3.4.5.4 The Current ESA Label Provides Conservative Dosing Guidance for Patients Who Do Not Adequately Respond to ESA Therapy The management of anemia in patients with CKD who respond poorly to ESA therapy remains a clinically relevant question. ESA hyporesponsiveness has been associated with poor clinical outcomes 122, however, no clinical trials have explicitly examined the question of whether the morbidity experienced by ESA hyporesponsive patients is a result of the ESA or the hyporesponsive state itself. Thus, as a prudent and cautious measure, the ESA USPIs were updated in 2007 to provide conservative dosing guidance for the management of patients with CKD with poor response to ESA therapy. This guidance was added limiting the number of ESA dose increases to no more than three for patients who do not attain a Hb level within the range of 10-12 g/dL despite the use of appropriate ESA dose titrations over a 12-week period 95. MEDCAC Background Information 3.4.6 Page 42 of 290 Page 40 There are No New Data in Dialysis Patients to Support a Change in the Labeled Hemoglobin Range of 10-12 g/dL and Data from Clinical Trials and Over 20 years of Clinical Experience Support this Range The benefits of ESA therapy, when used to manage anemia to a Hb range of 10-12 g/dL, have been demonstrated in numerous clinical trials and in clinical practice. RCTs targeting hemoglobin levels ≥ 13 g/dL 105, 106, 128, first reported in 1998, have shown increased CV and mortality risk, and therefore, the USPI reflects these risks and recommends not targeting these Hb levels. The most recent of these studies was completed in 2009 and was conducted in CKD-NOD patients and does not inform the benefits of ESA therapy in dialysis patients. The long-standing approach to anemia management, consistent with the USPI (treating to a Hb of 10-12 g/dL), has resulted in a marked decrease in transfusions, which are now reserved for the acute treatment of anemia (Figure 11). Treating to a lower Hb target would almost certainly increase the proportion of patients with Hb < 10 g/dL, which is known to be associated with a greater severity of anemia symptoms and a greater need for RBC transfusions. Since the intended benefit of ESA therapy includes transfusion avoidance, there is no rationale for lowering the target and accepting a higher transfusion rate. ESA therapy has been discussed in great depth at recent FDA and CMS advisory committee meetings. These meetings examined the benefits and risks of ESA therapy focusing on the appropriate therapeutic Hb range and patient populations. Select highlights include: • The September 2007 Cardiovascular and Renal Drugs Advisory Committee (CRDAC) panel reviewed the totality of available evidence from RCTs and 20 years of clinical practice data. Following the meeting, the USPI was revised and one of the important revisions included the re-establishment of the recommended therapeutic Hb range of 10-12 g/dL. • At the March 2010 MEDCAC meeting, the panel was asked to review a set of questions regarding the use of ESAs. The last of these questions asked if the CKD patient’s status (requiring dialysis or not requiring dialysis) would impact the assessment of risk and benefits related to ESA use. The panel acknowledged the significant differences between dialysis and CKD-NOD patients, and thus, decided to review the available evidence for the two populations separately. MEDCAC Background Information • Page 43 of 290 Page 41 Most recently, the October 2010 CRDAC panel reviewed the results of a large RCT of moderately anemic diabetic patients with moderate CKD-NOD, which demonstrated an increased risk of stroke with ESA treatment to a Hb target of 13 g/dL. In light of this recently completed study, the committee re-examined the benefits and risks of ESAs in CKD patients, on and not on dialysis. As this was the most recent review of the totality of evidence on the benefits and risks of ESAs, the specific questions and results of the panel votes from this meeting are provided below 129. Following the CRDAC panel meeting, discussions with FDA are ongoing. 3.4.7 The Prospective Payment System (PPS) will Impact the Use of ESAs Current ESA use has been effective at treating anemia and dramatically reducing the need for transfusions. However, forthcoming policy changes have the potential for reducing ESA use in the dialysis population. The new Medicare ESRD PPS is the most significant change to the way ESRD services are reimbursed since Congress mandated coverage of dialysis services in 1972, and was the result of considerable research and discussion within the nephrology community. The projected impact of the ESRD PPS removes incentives for overutilization of services and promotes increases in efficiencies in the management of patients. MEDCAC Background Information Page 44 of 290 Page 42 The concern has been raised that the inclusion of ESAs in the PPS may result in undesirable decreases in Hb concentrations as a result of inadequate ESA dosing, and may lead to an increase in blood transfusions, particularly among subpopulations with greater ESA dose requirements, such as African Americans 130, 131 and patients who exhibit poor Hb response 122. CMS recognized this concern specifically: “While the inclusion of any item or dialysis service in the payment bundle provides an incentive for dialysis facilities to maximize profits by skimping on the provision of that item or service, we point out that an important part of our Quality Incentive Program (QIP) is the monitoring of hemoglobin levels among dialysis patients to ensure that target levels are met, and that anemia management does not deteriorate under the ESRD PPS” (section II.M. of the final PPS rule). The QIP specifically penalizes providers who allow Hb concentrations to remain below 10 g/dL or above 12 g/dL, which is aligned with the Hb range in the FDA approved ESA labels. Additionally, CMS intends to monitor the incidence of transfusions and ensure that effective anemia management with ESAs is not replaced with transfusions. The registrational trials and the use of ESAs over the past 20 years in clinical practice have demonstrated a marked reduction in transfusions when ESAs are used to a therapeutic Hb range of 10-12 g/dL. Using ESAs to lower therapeutic Hb ranges would reduce the seminal benefit of ESAs. 3.4.8 Conclusion: ESAs are an Essential Therapy for Dialysis Patients ESAs are an essential therapy in the management of anemia in dialysis patients. Evidence from RCTs, as well as observational data, has strongly supported that maintaining Hb levels above 10 g/dL and within the range of approximately 10-12 g/dL with ESAs is essential for reducing transfusions and improving physical function and exercise tolerance. Additionally, by reducing exposure to transfusions, ESA therapy reduces the acute and long-term risks associated with transfusions, including volume, iron and electrolyte overload, infectious complications, and allosensitization. The use of ESAs to reduce transfusions is aligned with the FDA-approved label for red blood cell products 26. Avoidance of transfusions and consequent sensitization is a particularly relevant issue for patients who are, or may ever become, transplant candidates, in order to preserve the opportunity for successful transplantation and remove the dependency on dialysis. Treating to a Hb range of 10-12 g/dL with ESAs has been reviewed and is a reasonable therapeutic range for treatment of anemia and reduction of transfusion, while Page 45 of 290 MEDCAC Background Information Page 43 avoiding the high Hb targets where risks have been observed. There are no new data that alter the established benefits of ESAs in dialysis patients or support changes to the therapeutic Hb range of 10-12 g/dL for dialysis patients. Reducing the Hb target range would increase the rate of transfusion and expose patients to numerous transfusionrelated risks including allosensitization. There are no off-setting benefits to this strategy. 4. ANEMIA MANAGEMENT IN CKD PATIENTS NOT ON DIALYSIS 4.1 CKD-NOD Patients are Heterogeneous with Respect to Kidney Function, Prevalence and Severity of Anemia, and there is a SubPopulation who May Require Anemia Management Unlike patients on dialysis, who by definition have end-stage renal disease, and are almost universally anemic and require ESA treatment to maintain Hb levels, the population of patients with CKD not receiving dialysis is heterogeneous in terms of renal impairment and the prevalence and severity of anemia 6. The prevalence of significant anemia (Hb < 10 g/dL) is low in the early stages of renal disease and increases to approximately 20-30% in the small sub-population of patients in the later stages of the disease (Figure 21) 5. It is for this small population that treatment with ESA therapy can be beneficial. Figure 21. The Prevalence of Significant Anemia (Hb < 10 g/dL) According to Level of Kidney Function (Estimated Glomerular Filtration Rate [eGFR]; Lower eGFR Indicates More Severe Disease) 100 Patients with anemia (%) 90 80 70 60 50 40 30 20 10 0 > 60 30-<60 15-<30 eGFR (mL/min/1.73m2) <15 MEDCAC Background Information 4.2 Page 46 of 290 Page 44 Transfusions are Not Uncommon in CKD-NOD Patients with Significant Anemia Among Medicare patients with CKD-NOD and anemia, the annual transfusion rate is approximately 20-25%, three-fold higher than in CKD-NOD patients without anemia, and 10-fold higher than in those without CKD17. In 2004, there were approximately 400,000 anemic CKD-NOD patients covered by Medicare and an estimated 60,000-100,000 transfusion events annually 17. An analysis of approximately 83,000 CKD-NOD patients with anemia in the Veteran’s Administration (VA) healthcare system shows a similar transfusion burden in patients not receiving ESA therapy. In this population, the annual transfusion rate ranges from 20-40% depending on the severity of anemia (Figure 22), with a 1-year transfusion rate substantially higher in patients with a baseline Hb < 10 g/dL compared to Hb ≥ 10 g/dL 132. Figure 22. Annual Transfusion Rates in CKD-NOD Patients in the Absence of ESA Therapy (2002-2007) 4.3 RBC Transfusions Carry Similar Risks in CKD-NOD and Dialysis Patients In the CKD-NOD patient population, RBC transfusions carry similar risks to those in dialysis patients. The risks include transmission of viral disease, transfusion reactions, as well as transfusion-related complications such as acute volume overload and hyperkalemia; the volume and potassium-related risks occur at lower frequency than in dialysis patients 2, 18-21. Most important to the long-term outcome of these patients, RBC transfusions result in sensitization to foreign antigens 58, 71 that can be enduring and delay or preclude future kidney transplantation50 and impact overall graft survival in transplanted patients 61. Successfully transplanted patients have superior survival, and quality of life and incur lower health care costs 133. Therefore, avoidance of transfusion to maintain transplant eligibility is of critical importance in CKD-NOD patients, as the MEDCAC Background Information Page 47 of 290 Page 45 need for a transplant may occur prior to, or following, dialysis initiation 50. Currently, 15% of transplants occur in CKD-NOD patients near to but before initiation of dialysis 50. USRDS projects that ~700,000 patients will be receiving dialysis or be transplanted by the year 2020 50. The largest group progressing to dialysis is projected to be 45-64 yearolds, all of whom will become Medicare beneficiaries upon progressing to ESRD and many will be candidates for renal transplantation. 4.4 ESAs are an Effective Therapy for Managing Anemia in CKD-NOD Patients Data from multiple trials and clinical practice have demonstrated that ESAs raise and maintain Hb concentrations in anemic CKD-NOD patients 106, 107, 134, 135. In the original registrational studies with EPOGEN® in dialysis patients, transfusions were avoided when Hb concentrations were raised above 10 g/dL 117. Transfusion reduction was demonstrated in an open-label single-arm study of anemic CKD-NOD patients 135, where transfusion events were reduced by ~65% when Hb concentrations were raised above 10 g/dL and maintained to within the range of 10-12 g/dL. Transfusion reduction with ESA therapy has also been observed in general clinical practice in CKD-NOD patients. In the Medicare population with CKD-NOD and anemia, transfusion rates have declined as the proportion of patients receiving ESA treatment has increased 17. While not an FDA labeled benefit, a number of studies in CKD-NOD patients have shown varying degrees of improvement in PROs with ESA therapy 107, 136-138. Studies which initiated treatment at Hb < 10 g/dL and treated to targets > 10 g/dL have demonstrated more improvement in PROs than studies in which treatment was initiated when Hb > 10 g/dL 96. Several studies have shown that as Hb concentrations rise above 10 g/dL, CKD-NOD patients experience clinically meaningful improvement in physical function and vitality scores, as measured by various PRO instruments 139, 140 (Figure 23). Similar improvements have been demonstrated in scales measuring fatigue and activity levels 137, 141, 142. Page 48 of 290 MEDCAC Background Information Page 46 4.5 6.0 5.8 5.6 5.4 5.2 5.0 4.8 4.6 4.4 4.2 4.0 3.8 3.6 3.4 3.2 3.0 Spearman Correlation Coefficients r = 0.46; P < 0.0001 Physical Symptoms r = 0.42; P < 0.0001 Fatigue r = 0.24; P < 0.0001 Depression Relationship with others r = 0.29; P < 0.0001 r = 0.21; P < 0.0001 Frustration r = 0.38; P < 0.0001 Overall KDQ 35 30 25 20 15 Overall KDQ Score KDQ Score Figure 23. Hemoglobin Levels and Associated Kidney Disease Questionnaire (KDQ) Scores for Physical Symptoms, Fatigue, Depression, Relationship with Others, Frustration, and Overall KDQ (Clinically Meaningful Change in KDQ is 0.5) 108, 139, 143, 144 . 10 5 7 8 9 10 11 12 Hemoglobin level (g/100 mL) 13 14 0 ESAs should be considered in light of their labeled risks The USPI describes risks of ESAs and prescriber warnings. See section 3.4.4 for a description of these risks 95, 145. 4.6 Conclusion: ESA Therapy in CKD-NOD Patients is an Important Treatment Option in Those With Significant Anemia and for Whom Transfusion Avoidance is a Meaningful Clinical Outcome The prevalence of anemia requiring treatment is lower in CKD-NOD patients compared to that in dialysis patients. However, in some CKD-NOD patients, particularly those at the low end of the GFR spectrum nearing dialysis or being considered for pre-emptive transplant, anemia can be severe and transfusions are not uncommon. Anemic CKDNOD patients who receive transfusions are vulnerable to the same risks of transfusions, particularly the risk of sensitization, and its potential impact on transplant eligibility and graft survival, as patients on dialysis. Based on recently completed studies in CKD-NOD patients, Amgen has proposed label changes to limit the use of ESAs in CKD-NOD patients to those with significant anemia, who are at high risk for transfusion, and in whom transfusion avoidance is clinically meaningful. MEDCAC Background Information 5. Page 49 of 290 Page 47 CONCLUSION There are significant differences in the clinical characteristics of CKD patients requiring dialysis compared to CKD patients who do not. Dialysis patients, by definition, are at the end stage of renal disease and are reliant on the dialysis procedure to sustain life. Additionally, dialysis patients are almost universally anemic, with low Hb levels attributed to insufficient endogenous erythropoietin levels and ongoing blood loss which has been estimated to be 2.5-5 L annually, roughly equivalent to the blood volume of a normal adult. Anemia carries a significant burden causing symptoms such as fatigue, decreased energy, reduced physical function, and cognitive impairment, all of which can be severe and life-altering. Before ESA therapy was available, the treatment options for severe anemia were primarily limited to RBC transfusions. Dialysis patients were dependent on chronic transfusions and their quality of life remained poor. Transfusions were, and remain, only transiently effective in raising Hb concentrations in dialysis patients who are chronically unable to produce sufficient RBCs, and they have significant acute and long-term risks. The acute risks include volume overload, hyperkalemia, and transfusion reactions, and the long-term risks include iron overload, transmission of infectious diseases, and allosensitization to foreign antigens. Allosensitization, the development of antibodies to foreign antigens, is an important risk of transfusions for the CKD patient as it negatively impacts the likelihood and success of kidney transplantation, which is the optimal therapy for patients with end-stage renal disease. Allosensitization increases wait-time for a kidney transplant, reduces the likelihood of receiving a transplant, and increases the risk of acute graft rejection and long-term graft loss for those who do receive a transplant. The benefits of ESA therapy, when used to raise and maintain Hb concentrations above 10 g/dL to within a therapeutic range of approximately10-12 g/dL, have been demonstrated in registrational trials and in over 20 years of clinical practice. With the availability of ESAs, Hb concentrations increased, anemia symptoms improved, and transfusions decreased dramatically. With the decrease in transfusions, patients have had less exposure to transfusion-related risks and the proportion of patients on the renal transplant waiting list who have no sensitization has more than doubled. The totality of available evidence supports the current Hb range of 10-12 g/dL for ESA therapy in dialysis patients, which reduces transfusions and improves anemia symptoms, while accommodating Hb variability. In some CKD-NOD patients, particularly those at the low end of the GFR spectrum nearing dialysis or being considered for pre-emptive transplant, anemia can be severe MEDCAC Background Information Page 50 of 290 Page 48 and transfusions are not uncommon. Anemic CKD-NOD patients who receive transfusions are vulnerable to the same risks of transfusions, particularly the risk of sensitization, and its potential impact on transplant eligibility and graft survival, as patients on dialysis. 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Page 60 of 290 Appendix A - CMS Questions and Amgen's Responses Appendix A - CMS Questions and Amgen's Responses Page Page 61 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 1 MEDCAC –January 19, 2011 QUESTIONS Erythropoiesis Stimulating Agents (ESAs) for Treatment of Anemia in Adults with CKD Including Patients on Dialysis and Patients not on Dialysis: The Impact of ESA Use on Renal Transplant Graft Survival ESAs are used with the intention of reducing the need for red blood cell transfusion and thereby minimize immune sensitization as detected by panel reactive antibody (PRA) assays. PRA may be predictive of renal transplant graft survival. Some have proposed, therefore, that ESAs increase the survival of renal transplant grafts. For the voting questions, use the following scale identifying level of confidence - with 1 being the lowest or no confidence and 5 representing a high level of confidence. Please consider the questions in light of the following descriptive model. 1 Low confidence 2 3 Intermediate confidence 4 5 High confidence Page 62 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 2 1. How confident are you that there is adequate evidence to determine whether or not current panel reactive antibody (PRA) assays predict renal transplant graft survival for individual patients in contrast to populations? Confidence Level 4 Answer Supporting Evidence There is a high level of evidence indicating that PRA methods (assays) predict: 1) time on wait-list, 2) probability of never receiving a transplant, and 3) renal transplant graft survival. Although PRA methods have evolved, fundamentally, all PRA assays provide information regarding the presence and level of antibodies to foreign antigens (allosensitization). 1. Cecka et al. AJT 2010 ; 10 : 26-29 2. Gloor J et al. Nat Rev Nephrol. 2010;6:297306 3. USRDS 2010 Annual Data Report 4. UNOS 2009 Annual Report 5. Opelz et al., Lancet. 2005;365:1570-1576. 6. Ibrahim et al., Clin Transplant [in press] 7. Patel R et al. N Eng J Med, 1969 735-739 8. Tait et al., Nephrology 2009;14:247-254 9. Gloor J and Stegall M. Nat Rev Nephrol. 2010;6:297-306 10. Cecka et al. AJT 2010 ; 10 : 26-29 11. McKenna et al, Transplant 2000;69:319-326 12. Terasaki PI. Am J Transplant 2003;3:665673 The level of evidence used to guide therapies for individual patients is always established at the population level, through randomized controlled trials and/or large scale observational studies. For example, while it is not possible to predict how an individual will respond to lowering cholesterol levels with lipid lowering agents or lowering of blood pressure with anti-hypertensive therapies, the population benefit of these therapies has been sufficiently demonstrated in RCTs, and in so doing, allow physicians to apply them at the individual level. Similarly, observational studies have demonstrated associations between tobacco use and lung cancer and while it is not possible to predict whether any single individual who smokes will develop lung cancer, the evidence from large observational studies are used to guide recommendations that individuals should abstain from tobacco use. 1 The PRA test measures a patient’s level of sensitization to a representative pool of donor HLA antigens . The PRA, expressed as a percentage, reflects the percentage of the representative organ donor pool for which the potential recipient has alloantibodies (i.e. allosensitized)2. For example, a PRA of 70% suggests that 70% of donors will likely be unacceptable for the tested patient due to the presence of antiHLA antibodies against donor antigens. Thus, the higher the percent PRA, the more ‘allosensitized’ a patient is to the general donor pool, and the more difficult to find a suitable donor. Levels of allosensitization are often categorized and interpreted as no sensitization (PRA=0%), low degree of sensitization (0-<10% or < 20%), moderate degree of sensitization (20-<79%), and high degree of sensitization (≥ 80%). Page 63 of 290 Appendix A - CMS Questions and Amgen’s Responses Regardless of the method used to measure PRA, high PRA levels are strongly associated with: 1) longer time on the transplant wait-list, 2) higher probability of never receiving a transplant, and 3) worse kidney graft survival. Even when the crossmatch test is negative, a high pre-transplant PRA level is associated with shorter kidney survival. The evidence supporting these associations comes from complete population registries of transplant wait-list and transplanted patients (United Network for Organ Sharing [UNOS] and United States Renal Data System [USRDS]), and from multiple studies of over 50,000 transplanted patients 3-6. Historical PRA methods In 1969, Patel and Terasaki7 demonstrated that when a patient’s serum contained antibodies to a broad range of donor cells, randomly derived from different individuals in the general population, the patient had a much higher probability of experiencing acute organ rejection following transplantation. This was the basis for the panel reactive antibody test, which measures a patient’s level of sensitization to a representative pool of donor HLA antigens. The PRA, expressed as a percentage, reflects the percentage of the likely organ donor pool for which the potential recipient has alloantibodies (i.e. allosensitized). Current PRA methods In recent years, solid phase assays have been introduced that improve upon the cell-based assays for HLA antibody screening and have refined our understanding of sensitization8. These assays are more sensitive than previous methods in detecting HLA antibodies, and fall into two categories, ELISA-based and HLA antigen-coated beads used in either a Flow Cytometry system or a Luminex platform. The Luminex platform-based assay is now the standard methodology for assessing sensitization and determining organ allocation in the US 9. These tests allow the determination of a calculated PRA (cPRA). The cPRA is based upon HLA antigens to which the patient has been sensitized and which, if present in a donor, would represent an unacceptable risk for the candidate; these are referred to as unacceptable antigens. The cPRA is computed from HLA antigen frequencies among approximately 12,000 kidney donors in the United States between 2003 and 2005 and thus represents the percentage of actual organ donors that express one or more of those unacceptable HLA antigens10. Since 2009, transplant wait-list patients’ cPRA and their specific unacceptable antigens are required to be reported to UNOS in an effort to manage more fairly the allocation of organs for highly sensitized patients, who have likely spent considerable time on the transplant wait-list and cannot easily find a crossmatch negative (i.e.no donor specific antibodies) kidney due to the high levels of alloantibodies and broad sensitization. Page 3 13. Buscaroli A et al. Transplant Int. 1992;5:S54-S57 14. Terasaki PI et al. AJT 2010;4:438-443 15. Lefaucheur C et al. J Am Soc Nephrol. 2010;21:1398-1406 Page 64 of 290 Appendix A - CMS Questions and Amgen’s Responses Crossmatch Test A cross-match between a recipient and selected donor measures the presence of specific antibodies in the recipient’s blood that react with the donor’s cells. The crossmatch test is the gold standard for ultimately determining if a transplant will occur. A positive crossmatch corresponds with the presence of detectable specific anti-donor antibodies and is generally a contraindication to proceed with transplantation from that donor. In the face of a negative crossmatch, a transplant can proceed8. Evidence supporting the impact of PRA levels on graft outcomes at the population level: Terasaki and colleagues 11-12, in a series of papers, has summarized the evidence and synthesized the current view regarding the importance of antibodies in both acute and chronic graft rejection (approximately 50 independent publications). • In 2000, he reviewed 23 pubs in which the presence of HLA antibodies was associated with acute and chronic rejection11. • In 2003, he reviewed 35 studies, again showing an association between HLA antibodies and graft rejection12. Opelz et al.5 presents data from the Collaborative Transplant Study Group (N = 116,562) on the effect of PRA on cadaver renal transplant graft survival. At 10 years, the proportion of graft survival was 72.4% (no PRA), 63.3% (PRA 1-50%), and 55.5% (PRA > 50%). Patients with 1-50% pre-transplant PRA had increased relative risk of graft loss compared to non-sensitized patients (PRA=0%) (RR 1.29; 95% CI 1.09-1.53; P = 0.0033). The relative risk of graft loss was even higher in patients with pre-transplant PRA > 50% compared to non-sensitized patients (RR 1.87; 95% CI 1.47-2.37; P < 0.0001). Transplants from HLA-identical sibling donors do not provide a target for antibodies to HLA antigens and should therefore not be affected by PRA. However, higher PRA levels were strongly associated with long-term graft loss even in kidney transplants between siblings found to be HLA-identical by the transplant center prior to transplant. In a separate study of nearly 70,000 transplanted patients, Ibrahim et al.6 showed that PRA at the time of transplant was associated with a significantly elevated risk of death with graft failure or death with function. Those with a PRA of 20%-79% were at elevated risk compared to those with PRA=0% (HR=1.18, 95% CI: 1.11-1.26), after adjusting for differences in case-mix; this risk was even greater for those with a PRA > 80% (HR=1.30, 95% CI: 1.17-1.45). Buscaroli et al.13 evaluated intermediate sensitization (PRA 30% - 60%) compared to lower levels of sensitization (PRA < 30%) on kidney graft outcomes. Patients with intermediate sensitization had significantly lower 1-year graft survival than patients with lower levels of sensitization (79.3% vs. 90.4%). Page 4 Page 65 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 5 Terasaki et al.14 conducted a prospective trial in 23 kidney transplant centers (n=2231) to determine whether HLA antibodies could predict kidney transplant failure within 1 year. Among the 500 patients who had HLA antibodies, 6.6% failed compared to 3.3% among the 1778 patients without antibodies (p = 0.0007). Lefaucheur et al.15, evaluated the occurrence of acute antibody-mediated rejection and survival in kidney transplant patients with preexisting donor-specific HLA antibodies (HLA-DSA). The results showed patients with HLA-DSA had significantly lower 8-year graft survival compared to sensitized patients without HLA-DSA or non-sensitized (61% vs. 93% vs. 83.6%, P < 0.001). For a more comprehensive list of the publications cited in the McKenna11 and Terasaki12 publications, which evaluate the relationship between HLA antibodies, PRA methods, and kidney graft outcomes, see the reference list in Appendix B. 2. If the result of Question 1 is at least Intermediate (mean vote ≥ 2.5) how confident are you that current PRA assays predict renal transplant graft survival for individual patients? Confidence Level 4 Answer There is a high level of confidence that there is adequate evidence to determine that PRA assays predict 1) time on wait-list, 2) probability of never receiving a transplant, and 3) renal transplant graft survival. While the newer cPRA methods in use have higher sensitivity than previous methods, they do not alter the fact that there is a relationship between allosensitization and renal transplant graft survival. The level of evidence used to guide therapies for individual patients or investigate risk factors for adverse clinical outcomes is always established at the population level by way of RCTs and/or observational research. These findings are then applied to individuals. Regardless of the method used to measure PRA, high PRA levels are strongly associated with: 1) longer time on the transplant wait-list, 2) higher probability of never receiving a transplant, and 3) worse kidney graft survival. Even when the crossmatch test is negative, a high pre-transplant PRA level is associated with shorter kidney survival. Supporting Evidence 1. USRDS 2010 Annual Data Report 2. UNOS 2009 Annual Report 3. Opelz et al., Lancet. 2005;365:1570-1576. 4. Ibrahim et al., Clin Transplant [in press] 5. USRDS 2009 Annual Data Report 6. Meier-Kriesche et al., Transplantation 2002 ;74 :1377-81. 7. Buscaroli A et al. Transplant Int. 1992;5:S54-S57. Page 66 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 6 The evidence supporting the relationship between higher PRA levels and longer time on the wait-list, greater probability of never receiving a transplant and worse renal transplant graft survival comes from complete population registries of transplant wait-list and transplanted patients (United Network for Organ Sharing [UNOS] and United States Renal Data System [USRDS]), and from multiple studies of over 50,000 transplanted patients 1-4. The following figures illustrate these relationships. Higher PRA levels associated with longer wait-time5 Median Wait Time In Years 10 PRA <10 PRA 10+ 8 6 4 2 91 95 99 03 07 Years of Listing Longer time on the wait-list associated with greater likelihood of dying5 8. Terasaki PI et al. AJT 2010;4:438-443 9. Lefaucheur et al. JASN 2010;21:1398-1406. 10. OPTN Annual Report 2009 11. Susal C. Transplantation 2009;87: 1367–1371 12. Lachmann N. Transplantation. 2009;87(10):1505-13 13. Horovitz D et al. Transplantation 2009;87: 1214–1220 14. Yabu et al., Transplantation 2010 [in press] 15. Burns et al. AJT 2008;8:2684-2694 16. Mauiyyedi et al. JASN 2001; 17. Sayegh et al. NEJM 2003;348:1033-1044 18. Campos et al. AJT 2006;6:2316-2320 19. Gibney et al. NDT 2006;21:2625-2629 20. Karpinski et al. JASN 2001;12:2807-2814; 21. Mizutani et al. AJT 2005;5 :2265-2272 22. Mizutani et al. AJT 2007;7 :1027-2031 Page 67 of 290 Appendix A - CMS Questions and Amgen’s Responses Kidney graft survival in 21,836 recipients of living transplants by length of dialysis treatment before transplant6 Higher PRA levels associated with shorter graft survival in a) all transplanted patients and b) transplants between HLA-identical sibling donor-recipient pairs3 Page 7 23. Panigrahi et al. Hum Immunol 2007;68:362367 24. Smith et al. AJT 2007;7:2809-2815 25. McKenna et al, Transplant 2000;69:319-326 26. Terasaki PI. Am J Transplant 2003;3:665673 Page 68 of 290 Appendix A - CMS Questions and Amgen’s Responses Evidence supporting the impact of PRA levels on graft outcomes at the population level Opelz et al.3 presents data from the Collaborative Transplant Study Group (N = 116,562) on the effect of PRA on cadaver renal transplant graft survival. At 10 years, the proportion of graft survival was 72.4% (no PRA), 63.3% (PRA 1-50%), and 55.5% (PRA > 50%). Patients with 1-50% pre-transplant PRA had increased relative risk of graft loss compared to non-sensitized patients (PRA=0%) (RR 1.29; 95% CI 1.09-1.53; P = 0.0033). The relative risk of graft loss was even higher in patients with pre-transplant PRA > 50% compared to non-sensitized patients (RR 1.87; 95% CI 1.47-2.37; P < 0.0001). Transplants from HLA-identical sibling donors do not provide a target for antibodies to HLA antigens and should therefore not be affected by PRA. However, PRA reactivity was strongly associated with long-term graft loss even in kidney transplants between siblings found to be HLA-identical by the transplant center prior to transplant. In a separate study of nearly 70,000 transplanted patients, Ibrahim et al.4 showed that PRA at the time of transplant was associated with a significantly elevated risk of death with graft failure or death with function. Those with a PRA of 20%-79% were at elevated risk compared to those with PRA=0% (HR=1.18, 95% CI: 1.11-1.26), after adjusting for differences in case-mix; this risk was even greater for those with a PRA > 80% (HR=1.30, 95% CI: 1.17-1.45). Buscaroli et al.7 evaluated intermediate sensitization (PRA 30% - 60%) compared to lower levels of sensitization (PRA < 30%) on kidney graft outcomes. Patients with intermediate sensitization had significantly lower 1-year graft survival than patients with lower levels of sensitization (79.3% vs. 90.4%). Terasaki et al.8 conducted a prospective trial in 23 kidney transplant centers (n=2278) to determine whether HLA antibodies could predict kidney transplant failure within 1 year. Among the 500 patients who had HLA antibodies, 6.6% failed compared to 3.3% among the 1778 patients without antibodies (p = 0.0007). Lefaucheur et al.9 evaluated the occurrence of acute antibody-mediated rejection and survival in kidney transplant patients with preexisting donor-specific HLA antibodies (HLA-DSA). The results showed patients with HLA-DSA had significantly lower 8-year graft survival compared to sensitized patients without HLA-DSA or non-sensitized (61% vs. 93% vs. 83.6%, P < 0.001). Data supplied by the Organ Procurement and Transplantation Network’s (OPTN)10 Scientific Registry of Transplant Recipients (SRTR) showed disparities in graft survival for patients with elevated PRA at time of transplant. 1-year kidney graft survival rates were 91.7% (n = 36) for patients with PRA of > 80%, while patients with a PRA of 0-9% had a 96.2% (n = 1,469) graft survival rate. Page 8 Page 69 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 9 Susal et al.11 conducted a prospective multicenter study of over 1100 recipients of deceased donor kidney transplants demonstrated that human leukocyte antigen (HLA) class I antibodies present before transplantation were associated with a higher rate of delayed graft function and acute rejection episodes during the first 3 months after transplantation. This ultimately resulted in increased risk of graft loss by 3 years. Lachmann et al.12 showed with serial monitoring of HLA antibodies after transplantation using Luminex technology that patients with elevated antibody levels have lower 5-year graft survival compared to those without antibodies (79% vs. 95%). Horovitz et al13 evaluated graft outcomes from deceased donors comparing third renal transplants (TRTR) to primary renal transplants (PRTR). Patients with TRTR had higher PRA levels than the PRTR (24% vs 7%). TRTR patients experienced greater delayed graft function (46% vs 22%; P = 0.05) and biopsyproven rejection episodes (50% vs 29%; P = 0.01) compared to PRTR, despite greater frequency of induction therapy (74% vs 35%; P = 0.004). Evidence supporting the impact of PRA levels on graft outcomes at the individual level Several case studies have reported the association between HLA antibodies measured with cPRA methods and renal transplant graft survival. Higher levels of circulating antibodies have been associated with histological evidence of rejection in the transplanted kidney. Lowering the measured antibody levels with treatment has reversed the lesions and improved graft outcomes 14-24. For a more comprehensive list of the publications cited in the McKenna25 and Terasaki26 publications, which evaluate the relationship between HLA antibodies, PRA methods, and kidney graft outcomes, see the reference list in Appendix B. Discussion Question: 2a. How do PRA assays relate to more specific tests of HLA sensitivity and whether titer levels predict specific organ HLA sensitivity? Answer Regardless of the assay, high PRA levels indicate high levels of sensitization and predict a high likelihood of specific organ HLA sensitivity (a positive crossmatch). The crossmatch is the ultimate test done prior to transplantation to determine donor and recipient compatibility, and is the gold standard. A positive crossmatch corresponds with the presence of detectable specific anti-donor antibodies and is generally a contraindication to proceed with transplantation from that donor. In addition, the cPRA method is calculated from information on the presence of anti-HLA antibodies to specific antigens. Supporting Evidence 1. USRDS 2010 Annual Data Report 2. UNOS 2009 Annual Report 3. Opelz et al., Lancet. 2005;365:1570-1576. Page 70 of 290 Appendix A - CMS Questions and Amgen’s Responses The higher the level (PRA percentage) of sensitization, the less likely a patient is able to achieve a negative crossmatch. Regardless of the method used to measure PRA and even in the face of a negative crossmatch, high PRA levels predict: 1) longer time on the transplant wait-list, 2) higher probability of never receiving a transplant, and 3) worse kidney graft survival worse graft survival. The evidence supporting these associations comes from complete population registries of transplant wait-list and transplanted patients (United Network for Organ Sharing [UNOS] and United States Renal Data System [USRDS]), and from multiple studies of over 50,000 transplanted patients 1-4. cPRA methods are more sensitive than previous methods. PRA evaluations were performed using lymphocyte cytotoxicity (antiglobulin-enhanced, complement-dependent cytotoxicity [AHG-CDC]) or assays (enzyme-linked immunosorbent assay [ELISA]; flow cytometry) in which solubilized HLA molecules were affixed to solid phase matrices (n = 264 samples). Results among the three methods were concordant for 83% of these sera. Discordant results occurred with 32 samples and demonstrated a distinct hierarchy in the sensitivity of the three techniques to detect alloantibodies. None of the 32 sera were positive by AHG-CDC, 20/32 were positive by ELISA, and 32/32 were positive by flow cytometry5. UNOS convened a meeting of laboratory directors and transplant physicians in March 2008 to identify the problems of using solid phase testing. Evidence was presented from proficiency testing which revealed excellent concordance in identifying specific antibodies, even in complex antisera6. The development of PRA is cumulative7. The higher the PRA level, the greater the degree of sensitization and the greater the likelihood of a positive crossmatch. It is for this reason that patients with high PRAs have longer wait time on the list and may never find a suitable organ. Importantly, even if a patient with elevated PRA levels is able to find a suitable cross match negative kidney, these broadly sensitized patients have poorer graft survival than those who are not sensitized. Page 10 4. Ibrahim et al., Clin Transplant [in press] 5. Gebel H and Bray R. Clin Transplant. 2000;69:1370-1374. 6. US Department of Health and Human Services HHDoT. 2009 Annual Report of the U.S. Organ Procurement and Transplantation Network (OPTN) and the Scientific Registry of Transplant Recipients: Transplant Data 19992008. 7. USRDS 2004 Annual Data Report Discussion Question: 2b. Are the various proprietary PRA assays clinically interchangeable, i.e. would the treating physician’s management of the patient differ depending on the specific assay? Answer PRA methods are not interchangeable but provide the same information: PRA methods measure the presence and level of antibodies to foreign antigens. In addition, the cPRA method is calculated from information on the level of anti-HLA antibodies to specific HLA antigens. Supporting Evidence 1. USRDS 2010 Annual Data Report 2. UNOS 2009 Annual Report 3. Opelz et al., Lancet. 2005;365:1570-1576. Page 71 of 290 Appendix A - CMS Questions and Amgen’s Responses Regardless of the method used to measure PRA, high PRA levels are strongly associated with: 1) longer time on the transplant wait-list, 2) higher probability of never receiving a transplant, and 3) worse kidney graft survival. Even when the crossmatch test is negative, a high pre-transplant PRA level is associated with shorter kidney survival. The evidence supporting these associations comes from complete population registries of transplant wait-list and transplanted patients (United Network for Organ Sharing [UNOS] and United States Renal Data System [USRDS]), and from multiple studies of over 50,000 transplanted patients 1-4. Page 11 4. Ibrahim et al., Clin Transplant [in press] Discussion Question: 2c. Do current PRA assays provide the same clinical information as older assays, i.e. do historical data on the performance of PRA assays apply to currently available assays? Answer Yes, all PRA assays fundamentally provide information regarding the presence and level of antibodies to foreign antigens. The newer methods (cPRA) are calculated from information on the level of anti-HLA antibodies to specific HLA antigens. Older PRA methods were based on reacting the patient’s sera to a broad range of donor cells. In recent years, solid phase assays have been introduced that improve upon the cell-based assays for HLA antibody screening and have refined our understanding of sensitization1-3. These assays are more sensitive than previous methods in detecting HLA antibodies, and fall into two categories, ELISA-based and HLA antigen-coated beads used in either a Flow Cytometry system or a Luminex platform. The Luminex platform-based assay is now the standard methodology for assessing sensitization and determining organ allocation in the US2. Regardless of the method used to measure PRA, high PRA levels predict 1) longer time on wait-list, 2) greater probability of never receiving a transplant, and 3) worse kidney graft survival. Even when the crossmatch test is negative, a high pre-transplant PRA level predicts shorter kidney survival. This is supported by substantial evidence from multiple studies over many years using the older and current PRA methods.4-8 Supporting Evidence 1. Gloor J and Stegall M. Nat Rev Nephrol. 2010;6:297-306; 2. Cecka JM. A JT 2010;10:26-29. 3. Tait et al. Nephrology 2009;14:247-254 4. USRDS 2010 Annual Data Report 5. UNOS 2009 Annual Report 6. Opelz et al. Lancet. 2005;365:1570-1576. 7. Ibrahim et al., Clin Transplant [in press] 8. Lefaucheur et al. JASN 2010;21:1398-1406. Page 72 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 12 3. Donor-specific blood transfusions were frequently employed prior to renal transplantation for immune modulation and improved graft survival. These differ from therapeutic blood transfusions, which are performed for anemia/blood loss management. How confident are you that there is adequate evidence whether or not therapeutic blood transfusions decrease renal transplant graft survival? Confidence Level 4 Answer There is a substantial body of evidence demonstrating that red blood cell (RBC) transfusions administered for the therapy of anemia in CKD patients increase allosensitization, as measured by PRA levels. There is also substantial evidence demonstrating that higher PRA levels are strongly associated with: 1) longer time on the transplant wait-list, 2) higher probability of never receiving a transplant, and 3) worse kidney graft survival. The evidence supporting these associations comes from complete population registries of transplant wait-list and transplanted patients (United Network for Organ Sharing [UNOS] and United States Renal Data System [USRDS]), and from multiple studies of over 50,000 transplanted patients1-4. DSTs are distinctly different from therapeutic transfusions administered for anemia/blood loss management Donor specific transfusions (DSTs) were proposed as a method of inducing immune tolerance based on experimental consideration5, and first reported as potentially beneficial by Salvatierra in 19806. DST is a therapy consisting of transfusions of 1- 3 units of blood from the donor who is offering the kidney. These transfusions are administered to the recipient prior to the kidney transplant, with the intent of inducing immune tolerance to the donor kidney and improving the long-term kidney allograft survival7. DSTs, which can only be employed in the context of living donor kidneys, are distinctly different from therapeutic transfusions used for the treatment of anemia; therapeutic blood transfusions expose the recipient to blood from many unselected donors for the purpose of treating anemia. There is evidence supporting superior graft survival among living donor transplants in which DSTs were employed 8-12. However, it has also been reported that contrary to the intended purpose of inducing tolerance, up to 30% of prospective transplant recipients administered DSTs develop antibodies to the donor organ, thus precluding the organ transplant. While the patients who are allosensitized by DSTs remain eligible for other donor transplantation, living and deceased, the sensitization induced by the DST can compromise subsequent outcomes. Supporting Evidence 1. USRDS 2010 Annual Data Report 2. UNOS 2009 Annual Report 3. Opelz et al., Lancet. 2005;365:1570-1576. 4. Ibrahim et al. Clin Transplant [in press] 5. Opelz G et al. Transplant Proc. 1973;5:253-259. 6. Salvatierra et al. Ann Surg 1980;192:534–52 7. Cecka JM. AJT 2010;10:26-29. 8. Marti et al. Transpl Int 2006 9. Mackie F. Nephrol. 2010;15:S101-S105; 10. Okazaki H et al, Transplant Proc. 1997;29(1-2):200-2. 11. Anderson et al. Transplant Proc. 1995;27:991-4. 12. Aalten et al. NDT 2009;24:2559-2566 Page 73 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 13 Because of uncertainty about whether a DST will induce tolerance and improve graft outcomes or induce sensitization which can preclude a living donor transplant and reduce the transplant options of the patient, DST is no longer widely advised 13, 16, and has been abandoned by most transplant centers15 13. Sharma et al; Nephron.1997;75:20-4 14. Karpinski et al; JASN 2004;15:818-24 15. Alexander et al. Transplantation. 1999;68:1117-24. 4. If the result of Question 3 is at least Intermediate (mean vote ≥ 2.5) how confident are you that therapeutic blood transfusions decrease renal transplant graft survival? Confidence Level 4 Answer There is a high level of confidence that therapeutic blood transfusions decrease renal transplant graft survival. This has been shown in numerous large scale studies of transplant recipients. Analyses of the relationship between prior transfusions and transplant survival revealed that pretransplant transfusions are detrimental to graft survival. The figure below shows that graft survival is shortened as the number of pre-transplant transfusions increases, and this is evident for patients with lower (0-10%) and higher (>10%) levels of sensitization at the time of transplant1. Supporting Evidence 1. Hardy et al. Clin Transplants. 2001;271227. 2. O’Brien et al. American Society of Nephrology Congress Abstract 2010 3. USRDS 2010 Annual Data Report 4. UNOS 2009 Annual Report 5. Opelz et al. Lancet 2005;365:1570-1576. 6. Ibrahim et al., Clin Transplant [in press] Page 74 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 14 100 100 Percent Graft Survival PRA 0–10% PRA >10% 90 90 80 70 60 80 Number of transfusions N 0 18,086 1–5 8,126 6–10 993 >10 577 0 1 Number of N transfusions 3,816 0 2,871 1–5 427 6–10 333 >10 70 2 3 60 0 1 2 3 Years Posttransplant O’Brien et al. showed in a single centre retrospective cohort study that patients who received one blood transfusion had 52% graft survival at ten years, while those that received four transfusions had 41% graft survival at ten years. The effect of transfusion on graft survival was not changed after adjustment for donor and recipient age, and acute rejection not resulting in graft failure. 2 There is substantial evidence demonstrating that transfusions increase levels of allosensitization, and that higher PRA levels are strongly associated with: 1) longer time on the transplant wait-list, 2) higher probability of never receiving a transplant, and 3) worse kidney graft survival. The evidence supporting these associations comes from complete population registries of transplant wait-list and transplanted patients (United Network for Organ Sharing [UNOS] and United States Renal Data System [USRDS]), and from multiple studies of over 50,000 transplanted patients3-6. Evidence supporting that transfusions increase allosensitization and this effect is cumulative at the population level: USRDS 2004 data7 show that in patients on the transplant wait list (n~50,000), greater numbers of previous transfusions were significantly associated with PRA levels > 50%. 7. USRDS 2004 Annual Data Report 8. Soosay et al. Ir Med J. 2003;96:109-112 9. Ling et al. American Society of Nephrology Congress 2010 Poster. 10. Miller et al. Lancet 1975;895-893. 11. Moore et al. Vox Sang. 1984;47:354-361. 12. Aalten et al. NDT 2009;24:2559-2566 13. Opelz et al. Transplant Proc. 1973;5:253-259. 14. Lefaucheur et al. JASN 2010;21:1398-1406 Page 75 of 290 Appendix A - CMS Questions and Amgen’s Responses Recently, a study by Ibrahim et al.6 of approximately 70,000 transplant recipients showed that higher PRA levels were strongly and positively associated with previous transfusion in both males and females. Soosay et al.8 evaluated the relationship between transfusion and the risk of allosensitization. All highly sensitized patients (PRA > 80%) had received at least 1 unit of blood and there was a clear increase in the degree of sensitization with increasing numbers of units transfused, independent of other sensitizing events. Ling et al.9 assessed PRA levels in 778 patients on the kidney transplant wait list in a single center and determined that 198 patients were sensitized. Sixty-seven of 198 patients (33.8%) were sensitized by a single event (transfusion, prior transplantation, or pregnancy), of which 31.3% (n = 21) had received one or more blood transfusions and 47.8% (n = 32) had prior transplantation. Of the patients who had multiple events (n = 113), 98.2% had transfusions. Miller et al.10 showed that between 15% and 52% of patients who received blood products developed allosensitization. Moore et al.11 demonstrated that 77% of men and 86% of nulliparous women developed allosensitization (PRA of 1-10%) following one or more transfusions. Aalten et al.12 showed in a study of over 600 non-sensitized female patients, 20% became sensitized following receipt of a pre-transplant, donor-specific transfusion. Evidence supporting that allosensitization is associated with worse renal transplant graft survival at the population level: Opelz et al.13 presents data from the Collaborative Transplant Study Group (N = 116,562) on the effect of PRA on cadaver renal transplant graft survival. At 10 years, the proportion of graft survival was 72.4% (no PRA), 63.3% (PRA 1-50%), and 55.5% (PRA > 50%). Patients with 1-50% pre-transplant PRA had increased relative risk of graft loss compared to non-sensitized patients (PRA=0%) (RR 1.29; 95% CI 1.09-1.53; P = 0.0033). The relative risk of graft loss was even higher in patients with pre-transplant PRA > 50% compared to non-sensitized patients (RR 1.87; 95% CI 1.47-2.37; P < 0.0001). Transplants from HLA-identical sibling donors do not provide a target for antibodies to HLA antigens and should therefore not be affected by PRA. However, PRA reactivity was strongly associated with long-term graft loss even in kidney transplants between HLA-identical siblings Page 15 Page 76 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 16 In a separate study of nearly 70,000 transplanted patients, Ibrahim et al.6 showed that PRA at the time of transplant was associated with a significantly elevated risk of death with graft failure or death with function. Those with a PRA of 20%-79% were at elevated risk compared to those with PRA=0% (HR=1.18, 95% CI: 1.11-1.26), after adjusting for differences in case-mix; this risk was even greater for those with a PRA > 80% (HR=1.30, 95% CI: 1.17-1.45). Lefaucheur et al.14 evaluated the occurrence of acute antibody-mediated rejection and survival in kidney transplant patients with preexisting donor-specific HLA antibodies (HLA-DSA). The results showed patients with HLA-DSA had significantly lower 8-year graft survival compared to sensitized patients without HLA-DSA or non-sensitized (61% vs. 93% vs. 83.6%, P < 0.001). Discussion Question: 4a. The relative roles of sensitization as opposed to underlying co-morbid conditions in affecting renal transplant graft survival. Answer There are multiple factors that may influence graft survival in addition to PRA levels including patient demographic characteristics and co-morbid conditions. The available evidence suggests that PRA remains an independent predictor of graft failure. In a recent study of nearly 70,000 transplanted patients, Ibrahim et al.1 show that higher PRA levels were associated with significantly elevated risk of death or graft failure with death, even after adjusting for various clinical characteristics including demographics, blood type, dialysis modality, pre-listing duration on dialysis, and multiple co-morbid conditions. Those with a PRA of 20%-79% were at elevated risk compared to those with PRA=0% (HR=1.18, 95% CI: 1.11-1.26), after adjusting for differences in case-mix; this risk was even greater for those with a PRA > 80% (HR=1.30, 95% CI: 1.17-1.45). Supporting Evidence 1. Ibrahim et al. Clinical Transplantation 2010 [in press] Page 77 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 17 Discussion Question: 4b. The adequacy of the evidence based on the relationship if any between the number of units transfused and renal transplant graft survival. For example, is there a threshold number of units that predict renal transplant graft survival or is there a linear or exponential relationship between the number of units transfused that predict renal transplant graft survival? Answer Supporting Evidence Analyses of the relationship between prior transfusions and transplant survival show that pre-transplant transfusions are detrimental to graft survival. The figure below shows that graft survival is shortened as the number of pre-transplant transfusions increases, and this is evident for patients with lower (0-10%) and higher (>10%) levels of sensitization at the time of transplant1. 100 100 Percent Graft Survival PRA 0–10% PRA >10% 90 90 80 0 1–5 6–10 70 60 >10 0 80 N 18,086 8,126 993 70 577 1 0 1–5 6–10 2 3 60 N 3,816 2,871 427 >10 0 333 1 2 3 Years Posttransplant O’Brien et al.2 showed in a single centre retrospective cohort study that patients who received one blood transfusion had 52% graft survival at ten years, while those that received four transfusions had 41% graft survival at ten years. The effect of transfusion on graft survival was not changed after adjustment for donor and recipient age, and acute rejection not resulting in graft failure. Data from approximately 70,000 transplanted patients show that the patients who receive transfusions have higher risk of sensitization3 and the risk of allosensitization from RBC transfusion is cumulative: as the number of previous transfusions increases, so does the risk of elevated PRA levels4. 1. Hardy S, et al. Clin Transplants. 2001;271278. 2. O’Brien et al. American Society of Nephrology Congress Abstract 2010 3. Ibrahim et al., Clin Transplant [in press] 4. USRDS 2004 Annual Data Report Page 78 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 18 Discussion Question: 4c. The relative roles of blood transfusions, pregnancy, prior renal transplant, and other factors that cause sensitization. Answer There are only three recognized sources of HLA sensitization, of which, blood transfusions are the only clinically modifiable event. The ability of transfusions to induce sensitization can be amplified in the presence of previous sensitization. Hardy et al.1 stated in 2001: “rejection of a kidney was the most powerful means by which patients became sensitized. Transfusions were next in ability to sensitize followed by pregnancies.” Evidence supporting the relative role of blood transfusions on sensitization: Soosay et al.2 evaluated the relationship between transfusion and the risk of allosensitization. All highly sensitized patients (PRA > 80%) had received at least 1 unit of blood, in addition to other sensitizing events (ie, pregnancy (32%; prior transplantation 74%). In addition, there is a clear increase in the degree of sensitization with increasing number of units transfused, independent of other sensitizing events. Ling et al.3 assessed PRA levels in 778 patients on the kidney transplant wait list in a single center and determined that 198 patients were sensitized. Sixty-seven of 198 patients (33.8%) were sensitized by a single event (transfusion, prior transplantation, or pregnancy), of which 31.3% (n = 21) had received one or more blood transfusions and 47.8% (n = 32) had prior transplantation. Of the patients who had multiple events (n = 113), 98.2% had transfusions. Miller et al.4 showed that allosensitization by HLA antibodies ranged between 15% to 52% of patients who received blood products. Moore et al.5 demonstrated that 77% of men and 86% of nulliparous women developed allosensitization (PRA of 1-10%) following one or more transfusions. O’Brien et al.6 showed in a single centre retrospective cohort study that patients who received one blood transfusion had 52% graft survival at ten years, while those that received four transfusions had 41% graft survival at ten years. The effect of transfusion on graft survival was not changed after adjustment for donor and recipient age, and acute rejection not resulting in graft failure. Supporting Evidence 1. Hardy et al. Clin Transplants. 2001;271278 2. Soosay et al. Ir Med J. 2003;96:109-112 3. Ling et al. American Society of Nephrology Congress 2010 Poster. 4. Miller et al. Lancet 1975;895-893. 5. Moore S et al. Vox Sang. 1984;47:354-361. 6. O’Brien et al. . American Society of Nephrology Congress Abstract 2010 7. Vaidya S. Transplant Proc. 2005;37:648-649. 8. Rebibou et al. Transplant Immunology 2000;8:125-128 9. Scornik et al., Transplantation 1984;38:594-8. Page 79 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 19 Evidence supporting that the relative role of pregnancy on sensitization: In a retrospective study by Vaidya7, multiple pregnancies and ≥ 2 prior transfusions were both strongly associated with greater levels of sensitization. Rebibou et al.8 showed that in patients with previous pregnancies, transfusions induced sensitization in 36% of patients. Evidence supporting the relative role of prior renal transplant on sensitization: Rejection of a prior kidney transplant was the most powerful means by which patients became sensitized. Transfusions were next in ability to sensitize, followed by pregnancies1. Scornik et al.9 prospectively examined the development of sensitization following transfusion in patients who experienced graft failure without immediate sensitization. Among these patients, 18 received subsequent blood transfusion, and of those, over 70% were subsequently sensitized. 5. How confident are you that there is adequate evidence to determine whether or not ESA use for anemia/blood loss management improves renal transplant graft survival? Confidence Level Answer Supporting Evidence 4 ESAs are approved for the management of anemia in CKD patients. There is substantial evidence from registrational studies and data from near-universal capture of the US dialysis population that ESAs, when used to raise and maintain Hb within the range of ~10-12 g/dL, reduce the need for RBC transfusions. The level of confidence behind this conclusion is 5. 1. Eschbach et al. Ann Int Med.1989;111:9921000. ® 2. Aranesp USPI 3. Provenzano et al. Clin Nephrol. 2004;61:392405 4. USRDS 2007 Annual Data Report 5. Ibrahim et al. Nephrol Dial Transplant 2009;24: 3138–3143 6. USRDS 2004 Annual Data Report 7. Ibrahim et al., Clinical Transplant [in press] Reduction in transfusions reduces patient exposure to transfusion-related risks, including allosensitization, which is strongly associated with 1) longer time on wait-list, 2) higher probability of never receiving a transplant, and 3) shortened renal transplant graft survival. The level of confidence behind this conclusion is 4. Page 80 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 20 Evidence supporting that ESA therapy reduces the need for transfusions: The clinical benefit of transfusion avoidance in anemic dialysis patients was demonstrated in the registrational clinical trials with EPOGEN® and was the basis of approval1. Raising hemoglobin concentrations was the key outcome for approval of ESAs in the non-dialysis setting. The Aranesp®2 clinical trial program evaluated hemoglobin response in CKD-NOD subjects and demonstrated that hemoglobin levels could be raised and maintained within a targeted hemoglobin range and approval for this indication was granted by the FDA in 2001 (Amgen). In the original registration studies with EPOGEN® in dialysis patients, transfusion avoidance occurred when hemoglobin levels were raised above 10 g/dL 1, and maintained within a 2 g/dL range of approximately 10-12 g/dL. These trials demonstrated a virtual elimination of transfusions (> 90% reduction) in patients treated with ESAs compared to patients treated with placebo. While the Epoetin alfa treated patients became nearly transfusion independent, placebo treated patients remained severely anemic and continued to receive multiple transfusions. Similar efficacy was demonstrated in an open-label single-arm study of anemic CKD-NOD patients 3. In this study, hemoglobin levels were raised above 10 g/dL with ESA therapy and transfusion events were reduced by ~70%. Patients Transfused Per Quarter (%) Once ESA therapy was introduced into the US dialysis population, there was a dramatic decline in outpatient transfusions which persisted over time, as shown in the figure below from USRDS4. 16 12 8 4 0 78 80 82 84 86 88 Year 90 9. 10. 11. 12. 13. 14. Soosay et al. Ir Med J. 2003;96:109-112 Ling et al. American Society of Nephrology Congress 2010 Poster Miller et al. Lancet 1975;895-893. Moore et al. Vox Sang. 1984;47:354-361. Aalten et al. NDT 2009; 24: 2559-2566 O’Brien et al. American Society of Nephrology Congress Abstract 2010 Opelz et al. Lancet. 2005;365:1570-1576; 15. Buscaroli et al. Transplant Int. 1992;5:S54-S57 16. Terasaki et al. AJT 2010;4:438-443 17. Lefaucheur et al. JASN 2010;21:1398-1406. Use of ESAs Introduced 20 8. 92 94 96 Page 81 of 290 Appendix A - CMS Questions and Amgen’s Responses In the Medicare population with CKD-NOD and anemia, transfusion rates have declined from 30% to 15% among patients treated with ESAs between 1995 and 20045. Evidence supporting transfusions are associated with allosensitization: USRDS 2004 data show that in patients on the transplant wait-list (n~50,000) greater numbers of previous transfusions were significantly associated with PRA levels > 50%6. Recently, a study by Ibrahim et al.7 of approximately 70,000 transplant recipients showed that higher PRA levels were strongly and positively associated with previous transfusion in both males and females. Soosay et al.8 evaluated the relationship between transfusion and the risk of allosensitization. All highly sensitized patients (PRA > 80%) had received at least 1 unit of blood and there is a clear increase in the degree of sensitization with increasing number of units transfused, independent of other sensitizing events. Ling et al.9 assessed PRA levels in 778 patients on the kidney transplant wait list in a single center and determined that 198 patients were sensitized. Sixty-seven of 198 patients (33.8%) were sensitized by a single event (transfusion, prior transplantation, or pregnancy), of which 31.3% (n = 21) had received one or more blood transfusions and 47.8% (n = 32) had prior transplantation. Of the patients who had multiple events (n = 113), 98.2% had transfusions. Miller et al.10 showed that between 15% to 52% of patients who received blood products developed allosensitization. Moore et al.11 demonstrated that 77% of men and 86% of nulliparous women developed allosensitization (PRA of 1-10%) following one or more transfusions. Aalten et al.12 showed in a study of over 600 non-sensitized female patients, 20% became sensitized following receipt of a pre-transplant, donor-specific transfusion. O’Brien et al.13 showed in a single centre retrospective cohort study that patients who received one blood transfusion had 52% graft survival at ten years, while those that received four transfusions had 41% graft survival at ten years. The effect of transfusion on graft survival was not changed after adjustment for donor and recipient age, and acute rejection not resulting in graft failure. Page 21 Page 82 of 290 Appendix A - CMS Questions and Amgen’s Responses Evidence supporting allosensitization is associated with poor graph survival Opelz et al.14 presents data from the Collaborative Transplant Study Group (N = 116,562) on the effect of PRA on cadaver renal transplant graft survival. At 10 years, the proportion of graft survival was 72.4% (no PRA), 63.3% (PRA 1-50%), and 55.5% (PRA > 50%). Patients with 1-50% pre-transplant PRA had increased relative risk of graft loss compared to non-sensitized patients (PRA=0%) (RR 1.29; 95% CI 1.09-1.53; P = 0.0033). The relative risk of graft loss was even higher in patients with pre-transplant PRA > 50% compared to non-sensitized patients (RR 1.87; 95% CI 1.47-2.37; P < 0.0001). Transplants from HLA-identical sibling donors do not provide a target for antibodies to HLA antigens and should therefore not be affected by PRA. However, PRA reactivity was strongly associated with long-term graft loss even in kidney transplants between HLA-identical siblings. In a separate study of nearly 70,000 transplanted patients, Ibrahim et al.7 showed that PRA at the time of transplant was associated with a significantly elevated risk of death with graft failure or death with function. Those with a PRA of 20%-79% were at elevated risk compared to those with PRA=0% (HR=1.18, 95% CI: 1.11-1.26), after adjusting for differences in case-mix; this risk was even greater for those with a PRA > 80% (HR=1.30, 95% CI: 1.17-1.45). Buscaroli et al.15 evaluated intermediate sensitization (PRA 30% - 60%) compared to lower levels of sensitization (PRA < 30%) on kidney graft outcomes. Patients with intermediate sensitization had significantly lower 1-year graft survival than patients with lower levels of sensitization (79.3% vs. 90.4%). Terasaki et al.16 conducted a prospective trial in 23 kidney transplant centers (n=2278) to determine whether HLA antibodies could predict kidney transplant failure within 1 year. Among the 500 patients who had HLA antibodies, 6.6% failed compared to 3.3% among the 1778 patients without antibodies (p = 0.0007). Lefaucheur et al.17 evaluated the occurrence of acute antibody-mediated rejection and survival in kidney transplant patients with preexisting donor-specific HLA antibodies (HLA-DSA). The results showed patients with HLA-DSA had significantly lower 8-year graft survival compared to sensitized patients without HLA-DSA or non-sensitized (61% vs. 93% vs. 83.6%, P < 0.001). Page 22 Page 83 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 23 6. If the result of Question 5 is at least Intermediate (mean vote ≥ 2.5) how confident are you that there is adequate evidence to conclude that ESA use to maintain hemoglobin levels >10 g/dl is necessary to improve renal transplant graft survival? Confidence Level Supporting Evidence There is a high level of confidence that raising and maintaining hemoglobin concentrations > 10 g/dL and within the range of 10-12 g/dL significantly reduces the need for RBC transfusions 1,3. The level of confidence behind this conclusion is 5. Registrational trials in dialysis patients demonstrated that ESAs effectively raise Hb concentrations and significantly decrease the need for RBC transfusions3. Data from clinical trials and surveillance of the entire US dialysis population indicate that the likelihood of transfusions increases substantially when Hb concentrations fall below 10 g/dL, and this risk increases the longer Hb concentrations remain below 10 g/dL. The following figures support these conclusions. The level of confidence behind this conclusion is 5. Higher likelihood of transfusion when preceding month’s Hb is < 10 g/dL6. 8 7 6 The Risk of Transfusion by the Previous Month's Hemoglobin Level 5 4 Hazard Ratio (95% CI) 4 Answer 3 2.5 2 1.5 1.2 1 0.8 0.6 0.4 <9 9 - < 10 10 - < 11 11 - < 12 Hemoglobin level (g/dL) Data Source: NHCT study, data on file >=12 1. EPOGEN® USPI 2. Aranesp® USPI 3. Eschbach et al. Ann Int Med.1989;111:9921000 4. Provenzano et al. Clin Nephrol. 2004;61:392405; 5. Ibrahim et al. AJKD 2008;52:1115-1121. 6. Amgen Data on File 7. USRDS 2009 Annual Data Report 8. Ibrahim et al., NDT 2009;24:3138-3143 9. USRDS 2004 Annual Data Report 10. Ibrahim et al., Clinical Transplant [in press] 11. Soosay et al. Ir Med J. 2003;96:109-112 12. Ling et al. American Society of Nephrology Congress 2010 Poster. 13. Miller et al. Lancet 1975;895-893. 14. Moore et al. Vox Sang. 1984;47:354-361. Page 84 of 290 Appendix A - CMS Questions and Amgen’s Responses Transfusion rate increases substantially as the number of months with a Hb < 10 g/dL increases (Medicare hemodialysis data)6 Transfusion rate has declined significantly over time in dialysis patients as the mean hemoglobin concentration has increased to above 10 g/dL7 Page 24 15. Aalten et al. NDT 2009; 24: 2559-2566 16. O’Brien et al. . American Society of Nephrology Congress Abstract 2010 17. Opelz et al. Lancet. 2005;365:1570-1576 18. Buscaroli et al. Transplant Int. 1992;5:S54-S57. 19. Terasaki et al. AJT 2010;4:438-443 20. Lefaucheur et al. JASN 2010;21:1398-1406. Page 85 of 290 Appendix A - CMS Questions and Amgen’s Responses By raising and maintaining Hb concentrations above 10 g/dL and within the range of 10-12 g/dL, the risks related to transfusions are reduced. One of these risks is allosensitization, which has been consistently shown to impair the outcome of renal transplant including increased wait time for transplant as well as decreased renal transplant graft survival. This is shown in the figure below. The level of confidence behind this conclusion is 4. Evidence supporting that ESA therapy used to maintain hemoglobin concentrations > 10 g/dL and within the range of 10-12 g/dL decreases transfusions and their associated risks, including sensitization: The clinical benefit of transfusion avoidance in anemic dialysis patients was demonstrated by the registrational clinical trials with EPOGEN® and established hemoglobin as the key outcome for approval of ESAs in the non-dialysis setting. The Aranesp® clinical trial program evaluated hemoglobin response in CKD-NOD subjects and demonstrated that hemoglobin levels could be raised and maintained within a targeted hemoglobin range and approval for this indication was granted by the FDA in 2001 (Amgen). In the original registration studies with EPOGEN® in dialysis patients, transfusion avoidance occurred when hemoglobin levels were raised above 10 g/dL3, and maintained within a 2 g/dL range of approximately 10-12 g/dL. These trials demonstrated a virtual elimination of transfusions (> 90% reduction) in patients treated with ESAs compared to patients treated with placebo. While the Epoetin alfa treated patients became nearly transfusion independent, placebo treated patients remained severely anemic and continued to receive multiple transfusions. Similar efficacy was demonstrated in an open-label single-arm study of anemic CKD-NOD patients4. In this study, hemoglobin levels were raised above 10 g/dL with ESA therapy and transfusion events were reduced by ~70%. Data from the entire US hemodialysis patient population indicate that as Hb levels have increased over time with ESA therapy to a mean above 10 g/dL (~11.2 g/dL), transfusions have declined significantly and the proportion of un-sensitized transplant candidates has more than doubled from 24% to 49%5. In the Medicare population with CKD-NOD and anemia, transfusion rates have declined from 30% to 15% among patients treated with ESAs between 1995 and 20048. Evidence supporting that transfusions are associated with allosensitization: USRDS 2004 data9 show that in patients on the transplant wait list (n~50,000), greater numbers of previous transfusions were significantly associated with PRA levels > 50%. More recently, a study by Ibrahim et al.10 of approximately 70,000 transplant recipients showed that higher PRA levels were strongly and positively associated with previous transfusion in both males and females. Page 25 Page 86 of 290 Appendix A - CMS Questions and Amgen’s Responses Soosay et al.11 evaluated the relationship between transfusion and the risk of allosensitization. All highly sensitized patients (PRA > 80%) had received at least 1 unit of blood and there is a clear increase in the degree of sensitization with increasing number of units transfused, independent of other sensitizing events. Ling et al.12 assessed PRA levels in 778 patients on the kidney transplant wait list in a single center and determined that 198 patients were sensitized. Sixty-seven of 198 patients (33.8%) were sensitized by a single event (transfusion, prior transplantation, or pregnancy), of which 31.3% (n = 21) had received one or more blood transfusions and 47.8% (n = 32) had prior transplantation. Of the patients who had multiple events (n = 113), 98.2% had transfusions. Miller et al.13showed that between 15% to 52% of patients who received blood products developed allosensitization. Moore et al.14 demonstrated that 77% of men and 86% of nulliparous women developed allosensitization (PRA of 1-10%) following one or more transfusions. Aalten et al.15 showed in a study of over 600 non-sensitized female patients, 20% became sensitized following receipt of a pre-transplant, donor-specific transfusion. O’Brien et al.16 showed in a single centre retrospective cohort study that patients who received one blood transfusion had 52% graft survival at ten years, while those that received four transfusions had 41% graft survival at ten years. The effect of transfusion on graft survival was not changed after adjustment for donor and recipient age, and acute rejection not resulting in graft failure. Evidence supporting allosensitization is associated with poor graph survival: Opelz et al.17 presents data from the Collaborative Transplant Study Group (N = 116,562) on the effect of PRA on cadaver renal transplant graft survival. At 10 years, the proportion of graft survival was 72.4% (no PRA), 63.3% (PRA 1-50%), and 55.5% (PRA > 50%). Patients with 1-50% pre-transplant PRA had increased relative risk of graft loss compared to non-sensitized patients (PRA=0%) (RR 1.29; 95% CI 1.09-1.53; P = 0.0033). The relative risk of graft loss was even higher in patients with pre-transplant PRA > 50% compared to non-sensitized patients (RR 1.87; 95% CI 1.47-2.37; P < 0.0001). Transplants from HLA-identical sibling donors do not provide a target for antibodies to HLA antigens and should therefore not be affected by PRA. However, PRA reactivity was strongly associated with long-term graft loss even in kidney transplants between HLA-identical siblings. Page 26 Page 87 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 27 In a separate study of nearly 70,000 transplanted patients, Ibrahim et al.10 showed that PRA at the time of transplant was associated with a significantly elevated risk of death with graft failure or death with function. Those with a PRA of 20%-79% were at elevated risk compared to those with PRA=0% (HR=1.18, 95% CI: 1.11-1.26), after adjusting for differences in case-mix; this risk was even greater for those with a PRA > 80% (HR=1.30, 95% CI: 1.17-1.45). Buscaroli et al.18 evaluated intermediate sensitization (PRA 30% - 60%) compared to lower levels of sensitization (PRA < 30%) on kidney graft outcomes. Patients with intermediate sensitization had significantly lower 1-year graft survival than patients with lower levels of sensitization (79.3% vs. 90.4%). Terasaki et al.19 conducted a prospective trial in 23 kidney transplant centers (n=2278) to determine whether HLA antibodies could predict kidney transplant failure within 1 year. Among the 500 patients who had HLA antibodies, 6.6% failed compared to 3.3% among the 1778 patients without antibodies (p = 0.0007). Lefaucheur et al.20 evaluated the occurrence of acute antibody-mediated rejection and survival in kidney transplant patients with preexisting donor-specific HLA antibodies (HLA-DSA). The results showed patients with HLA-DSA had significantly lower 8-year graft survival compared to sensitized patients without HLA-DSA or non-sensitized (61% vs. 93% vs. 83.6%, P < 0.001). 7. What significant evidence gaps exist regarding the clinical criteria, including hemoglobin level, of patients who should receive blood transfusions for chronic anemia with the intent of improving renal transplant graft survival? Answer There is no evidence gap on the question of use of therapeutic transfusions for the treatment of anemia with the intent of improving graft survival; they should not be used for this purpose. There is a substantial body of evidence demonstrating that red blood cell (RBC) transfusions administered for the therapy of anemia in CKD patients increase allosensitization, as measured by PRA levels. There is also substantial evidence demonstrating that higher PRA levels are strongly associated with decreased renal transplant survival. The evidence supporting the relationship between PRA methods and worse renal transplant graft survival comes from multiple studies of over 50,000 transplanted patients1. Supporting Evidence 1. Cecka et al. AJT. 2010;10:26-29. 2. Opelz et al. Lancet. 2005;365:1570-1576 3. Ibrahim et al., Clinical Transplantation [in press Page 88 of 290 Appendix A - CMS Questions and Amgen’s Responses Therapeutic Blood Transfusions The evidence linking therapeutic transfusions with allosensitization is unequivocal in CKD patients: allosensitization significantly worsens renal transplant graft survival2,3. This has been established in multiple large studies and from surveillance of the entire dialysis and transplant populations (USRDS4 and UNOS5). • RBC transfusions increase allosensitization (as measured by PRA levels); • Higher PRA levels decrease the likelihood of finding a suitable donor, increasing the wait-time for a renal transplant, resulting in: o Increased probability of future transfusion and allosensitization o Increased probability of death while waiting for the transplant o Decreased probability of graft survival following transplantation. • Higher PRA levels increase acute and chronic graft rejection and shorten graft survival (time spent not on dialysis), even for patients with a negative cross-match. 6 A recent review article by Cecka concluded: "With the highly effective immunosuppressive drugs currently available, deliberate administration of donor transfusions represents an indefensible risk of sensitization and delay of transplantation without compensatory benefits." A recent review by the Circular of Information for the use of human blood and blood components7 concluded the following about the use of RBC transfusions: “Red-cell-containing components should not be used to treat anemias that can be corrected with specific hematinic medications such as iron, vitamin B12, folic acid, or erythropoietin.” Page 28 4. USRDS 2010 Annual Data Report 5. UNOS 2009 Annual Report 6. Cecka JM. Annu Rev Med 2000;51:393-406 (p. 401). 7. AABB, Circular of Information for the use of human blood and blood components, 2009 Page 89 of 290 Appendix A - CMS Questions and Amgen’s Responses Page 29 8. What significant gaps exist regarding the relationship, if any, of number of units transfused, screening PRA assays, more specific HLA assays, immune suppressive regimen, and the timing of rejection to determine the role various factors in transplant graft survival outcomes? Answer The highly sensitized patient remains a challenge to clinical transplantation. There is irrefutable evidence that transfusions, pregnancy and previous transplant can lead to sensitization and that sensitization predicts worse graft survival. Additional research in the following areas may be helpful: • PRA methods • Desensitization approaches • Optimal immunosuppressive regimen and approach to post-transplant management of highly sensitized patients • Identification of methods to prevent allosensitization • Identification of patients who are more likely to be sensitized Supporting Evidence Appendix B - Select References Appendix B - Select References Page 90 of 290 Page Page 91 of 290 CIRCULAR OF INFORMATION FOR THE USE OF HUMAN BLOOD AND BLOOD COMPONENTS This Circular was prepared jointly by AABB, the American Red Cross, America’s Blood Centers, and the Armed Services Blood Program (August 2009, revised December 2009). The Food and Drug Administration recognizes this Circular of Information as an acceptable extension of container labels. The online version of this Circular of Information is provided for educational purposes. It may not be modified in any way without the express permission of the AABB, ARC, ABC, and ASBP. Printed copies of the Circular are intended to accompany blood and blood components, and can be ordered through the AABB sales department or the online Bookstore. Please refer to this Web site’s “Terms of Use” for additional information. Federal Law prohibits dispensing the blood and blood components described in this circular without a prescription. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 92 of 290 Table of Contents Notice to All Users............................................................................................................. 1 General Information for Whole Blood and All Blood Components ......................................................................................................... 1 Donors ............................................................................................................................ 1 Testing of Donor Blood.................................................................................................. 1 Blood and Component Labeling..................................................................................... 2 Instructions for Use ........................................................................................................ 3 Side Effects and Hazards for Whole Blood and All Blood Components ......................................................................................................... 4 Immunologic Complications, Immediate ....................................................................... 4 Immunologic Complications, Delayed ........................................................................... 5 Nonimmunologic Complications.................................................................................... 5 Fatal Transfusion Reactions ........................................................................................... 7 Components Containing Red Cells.................................................................................. 7 Overview ........................................................................................................................ 7 Components Available ................................................................................................. 10 Plasma Components........................................................................................................ 12 Overview ...................................................................................................................... 12 Fresh Frozen Plasma..................................................................................................... 13 Plasma Frozen Within 24 Hours After Phlebotomy ..................................................... 14 Plasma Cryoprecipitate Reduced.................................................................................. 15 Liquid Plasma Components.......................................................................................... 15 Cryoprecipitated Components....................................................................................... 17 Overview ...................................................................................................................... 17 Components Available ................................................................................................. 18 Platelet Components ....................................................................................................... 18 Overview ...................................................................................................................... 18 Components Available ................................................................................................. 21 Granulocyte Components............................................................................................... 22 Further Processing.......................................................................................................... 23 Leukocyte Reduction.................................................................................................... 24 Further Testing to Identify CMV-Seronegative Blood................................................. 24 Irradiation ..................................................................................................................... 25 Washing ........................................................................................................................ 25 Volume Reduction........................................................................................................ 26 References........................................................................................................................ 26 Tables Table 1. Contents of Anticoagulant-Preservative Solutions........................................... 8 Table 2. Content of Additive Solutions (in mg/100 mL)................................................ 8 Table 3. Coagulation Factor Activity of Thawed Plasma Derived from FFP......................................................................................... 15 Table 4. Summary Chart of Blood Components .......................................................... 34 For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 93 of 290 1 Notice to All Users The Circular of Information for the Use of Human Blood and Blood Components (hereafter referred to as Circular) is an extension of container labels, as the space on those labels is limited. Blood and blood components are biologic products and, in the form of cellular products, living human tissue intended for use in patient treatment. Professional judgment based on clinical evaluation determines the selection of components, dosage, rate of administration, and decisions in situations not covered in this general statement. This Circular, as a whole or in part, cannot be considered or interpreted as an expressed or implied warranty of the safety or fitness of the described blood or blood components when used for their intended purpose. Attention to the specific indications for blood components is needed to prevent inappropriate transfusion. Because of the risks associated with transfusion, physicians should be familiar with alternatives to allogeneic transfusion. Blood banks and transfusion services are referred to the AABB Standards for Blood Banks and Transfusion Services for additional information and policies, especially in the areas of recipient sample identification, compatibility testing, issue and transfusion of blood and blood components, investigation of transfusion reactions, and proper record-keeping practices. Transfusionists are referred to the AABB Technical Manual for applicable chapters on adult and pediatric transfusion. The specific product manufacturer’s package insert should be reviewed for instructions pertaining to use of transfusion devices (eg, filters, blood administration sets, and blood warmers). This Circular is supplied to conform with applicable federal statutes and regulations of the Food and Drug Administration (FDA), United States (US) Department of Health and Human Services. The blood components in this Circular marked with the symbol “Ω ” are blood components for which FDA currently has not received data to demonstrate that they meet prescribed requirements of safety, purity, and potency, and therefore are not licensed for distribution in interstate commerce. General Information for Whole Blood and All Blood Components Donors Blood and blood components described in this Circular have been collected from volunteer blood donors for use in other patients (allogeneic transfusions) or from patients donating for themselves (autologous transfusions). The donors have been questioned about risk factors for transmissible infectious agents, have satisfactorily completed a health assessment that includes a questionnaire on past and present illnesses, have satisfied minimum physiologic criteria, and may have had the opportunity to confidentially exclude their donation from transfusion. Testing of Donor Blood Testing of a sample of donor blood is performed before units of blood or blood components are distributed for routine transfusion. The donor’s ABO group and Rh type have been determined, including testing for the presence of weak D antigen. A sample from each donation intended for allogeneic use has been tested by FDA-licensed tests and found to be nonreactive for antibodies to human immunodeficiency virus (anti-HIV1/2), hepatitis C virus (anti-HCV), human T-cell lymphotropic virus (anti-HTLV-I/II), and hepatitis B core antigen (anti-HBc), and nonreactive for hepatitis B surface antigen (HBsAg). For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 94 of 290 2 Licensed nucleic acid tests (NAT) for HCV ribonucleic acid (RNA), HIV-1 RNA, and West Nile virus (WNV) RNA have been performed and found to be nonreactive. A serologic test for syphilis has been performed and found to be nonreactive. For units labeled “FOR AUTOLOGOUS USE ONLY,” infectious disease testing requirements vary depending on whether the unit will be drawn in one facility and infused in another facility and whether the unit might be made available for allogeneic transfusion. Infectious disease testing may be omitted for autologous units drawn, stored, and infused at the same facility. Autologous units for which testing has not been performed are labeled “DONOR UNTESTED.” Autologous units with reactive test results may be used for transfusion to the donor-patient with appropriate physician authorization. A biohazard label will be applied to autologous units that are tested for evidence of infection as listed above and determined to be reactive. If the units labeled “FOR AUTOLOGOUS USE ONLY” are infused at a different facility, at a minimum the first donation from the donor-patient in each 30-day period is tested for evidence of infection as listed above. Subsequent units that are not tested will be labeled as “DONOR TESTED WITHIN THE LAST 30 DAYS.” If an establishment allows any autologous donation to be available for allogeneic transfusion, or ships autologous donations to any establishment that does, the collecting establishment must test each donation for evidence of infection as listed above. This includes units labeled “FOR AUTOLOGOUS USE ONLY.” Tests for unexpected antibodies against red cell antigens have been performed on samples from all donors. The results of these tests are negative or have been determined to be clinically insignificant unless otherwise indicated on the label. Other tests may have been performed on donor blood as indicated by information that has been provided by the blood bank or transfusion service on an additional label or tie tag, or in a supplement to this Circular. Blood and Component Labeling All blood components identified in this Circular have the ISBT 128 product name listed first and other recognized component names in parentheses. Blood and blood component labels will contain the following information: 1. The proper name, whole blood or blood component, including an indication of any qualification or modification. 2. The method by which the blood component was prepared, either by whole blood or apheresis collection. 3. The temperature range in which the blood component is to be stored. 4. The preservatives and anticoagulant used in the preparation of the blood or blood components, when appropriate. 5. The standard contents or volume is assumed unless otherwise indicated on the label or in Circular supplements. 6. The number of units in pooled blood components and any sedimenting agent used during cytapheresis, if applicable. 7. The name, address, registration number, and US license number (if applicable) of the collection and processing location. 8. The expiration date (and time if applicable), which varies with the method of preparation (open or closed system) and the preservatives and anticoagulant used. When the expiration time is not indicated, the product expires at midnight. 9. The donation (unit or pool) identification number. 10. The donor category (paid or volunteer, and autologous if applicable). 11. ABO group and Rh type, if applicable. 12. Special handling information, as required. 13. Statements regarding recipient identification, this Circular, infectious disease risk, and prescription requirement. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 95 of 290 3 Instructions for Use The following general instructions pertain to Whole Blood and all the blood components described in this Circular: 1. All blood and blood components must be maintained in a controlled environment and stored under appropriate conditions as described in the AABB Standards for Blood Banks and Transfusion Services. 2. The intended recipient and the blood container must be properly identified before the transfusion is started. 3. Aseptic technique must be employed during preparation and administration. If the container is entered in a manner that violates the integrity of the system, the component expires 4 hours after entry if maintained at room temperature (20-24 C), or 24 hours after entry if refrigerated (1-6 C). 4. All blood components must be transfused through a filter designed to remove clots and aggregates (generally a standard 170- to 260-micron filter). 5. Blood and blood components should be mixed thoroughly before use. 6. Blood and blood components must be inspected immediately before use. If, upon visual inspection, the container is not intact or the appearance is abnormal (presence of excessive hemolysis, a significant color change in the blood bag as compared with the tubing segments, floccular material, cloudy appearance, or other problems), the blood or blood component must not be used for transfusion and appropriate follow-up with the transfusion service must be performed. 7. No medications or solutions may be routinely added to or infused through the same tubing with blood or blood components with the exception of 0.9% Sodium Chloride, Injection (USP), unless 1) they have been approved for this use by the FDA or 2) there is documentation available to show that the addition is safe and does not adversely affect the blood or blood component. 8. Lactated Ringer’s, Injection (USP) or other solutions containing calcium should never be added to or infused through the same tubing with blood or blood components containing citrate. 9. Blood components should be warmed if clinically indicated for situations such as exchange or massive transfusions, or for patients with cold-reactive antibodies. Warming must be accomplished using an FDA-cleared warming device so as not to cause hemolysis. 10. Some life-threatening reactions occur after the infusion of only a small volume of blood or blood components. Therefore, unless otherwise indicated by the patient’s clinical condition, the rate of infusion should initially be slow. 11. Periodic observation and recording of vital signs should occur during and after the transfusion to identify suspected adverse reactions. If a transfusion reaction occurs, the transfusion must be discontinued immediately and appropriate therapy initiated. The infusion should not be restarted unless approved by transfusion service protocol. 12. Specific instructions concerning possible adverse reactions shall be provided to the patient or a responsible caregiver when direct medical observation or monitoring of the patient will not be available after transfusion. 13. Transfusion should be started before component expiration and completed within 4 hours. 14. All adverse events related to transfusion, including possible bacterial contamination of blood or a blood component or suspected disease transmission, must be reported to the transfusion service according to its local protocol. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 96 of 290 4 Side Effects and Hazards for Whole Blood and All Blood Components Immunologic Complications, Immediate 1. Hemolytic transfusion reaction, the destruction of red cells, is discussed in detail in the section on components containing red cells and in the platelet section. 2. Immune-mediated platelet destruction, one of the causes of refractoriness to platelet transfusion, is the result of alloantibodies in the recipient to HLA or platelet-specific antigens on transfused platelets. This is described in more detail in the section on platelets. 3. Febrile nonhemolytic reaction is typically manifested by a temperature elevation of ≥1 C or 2 F occurring during or shortly after a transfusion and in the absence of any other pyrexic stimulus. This may reflect the action of antibodies against white cells or the action of cytokines, either present in the transfused component or generated by the recipient in response to transfused elements. Febrile reactions may occur in approximately 1% of transfusions, and they occur more frequently in patients receiving non-leukocyte-reduced platelets and those previously alloimmunized by transfusion or pregnancy. No routinely available pre- or posttransfusion tests are helpful in predicting or preventing these reactions. Antipyretics usually provide effective symptomatic relief. Patients who experience repeated, severe febrile reactions may benefit from receiving leukocyte-reduced components. If these reactions are caused by cytokines in the component, prestorage leukocyte reduction may be benefical. 4. Allergic reactions frequently occur as mild or self-limiting urticaria or wheezing that usually respond to antihistamines. More severe manifestations including respiratory and cardiovascular symptoms are more consistent with anaphylactoid/anaphylactic reactions and may require more aggressive therapy (see below). No laboratory procedures are available to predict these reactions. 5. Anaphylactoid/anaphylactic reactions, characterized by hypotension, tachycardia, nausea, vomiting and/or diarrhea, abdominal pain, severe dyspnea, pulmonary and/or laryngeal edema, and bronchospasm and/or laryngospasm, are rare but dangerous complications requiring immediate treatment with epinephrine. These reactions have been reported in IgAdeficient patients who develop IgA antibodies. Such patients may not have been previously transfused and may develop symptoms after infusion of very small amounts of IgAcontaining plasma, in any blood component. Similar reactions have also been described in patients with haptoglobin deficiency. In certain circumstances, patients might benefit from the use of washed cellular components to prevent or reduce the severity of allergic reactions not minimized by treatment with medication alone. 6. Transfusion-related acute lung injury (TRALI) is the acute onset of hypoxemia within 6 hours of a blood or blood component transfusion and is the most commonly reported cause of transfusion-related deaths in the United States. In addition to hypoxemia, criteria for diagnosis include the presence of bilateral infiltrates on frontal chest radiographs and the exclusion of transfusion-associated circulatory overload (TACO), or preexisting acute lung injury. The exact mechanism of TRALI is not known, but hypotheses include donor antibodies that react against white cell antigens (HLA or human neutrophil antigens) and the sequestration of neutrophils by the pulmonary endothelium (caused by the recipient’s underlying condition) that are subsequently activated by the infusion of substances in the donor plasma such as antibodies or other biologically active substances. In far fewer cases, antibodies in the recipient that may react with antigens on transfused white cells have been implicated. Laboratory testing does not alter management of this reaction, which is diagnosed For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 97 of 290 5 mainly on clinical and radiographic findings. Treatment of TRALI requires aggressive respiratory support, frequently requiring mechanical ventilation. Immunologic Complications, Delayed 1. Delayed hemolytic reaction is described in detail in the section on components containing red cells. 2. Alloimmunization to antigens of red cells, white cells, platelets, or plasma proteins may occur unpredictably after transfusion. Blood components may contain certain immunizing substances other than those indicated on the label. For example, platelet components may also contain red cells and white cells. Primary immunization does not become apparent until days or weeks after the immunizing event, and does not usually cause symptoms or physiologic changes. If components that express the relevant antigen are subsequently transfused, there may be accelerated removal of cellular elements from the circulation and/or systemic symptoms. Clinically significant antibodies to red cell antigens will ordinarily be detected by pretransfusion testing. Alloimmunization to antigens of white cells, platelets, or plasma proteins can be detected only by specialized testing. 3. Posttransfusion purpura (PTP) is a rare syndrome characterized by the development of dramatic, sudden, and self-limited thrombocytopenia, typically 7 to 10 days after a blood transfusion, in a patient with a history of sensitization by either pregnancy or transfusion. Although the immune specificity may be to a platelet-specific antigen the patient lacks, both autologous and allogeneic platelets are destroyed. High-dose Immune Globulin, Intravenous (IGIV) may correct the thrombocytopenia. 4. Transfusion-associated graft-vs-host disease (TA-GVHD) is a rare but extremely dangerous condition that occurs when viable T lymphocytes in the transfused component engraft in the recipient and react against recipient tissue antigens. TA-GVHD can occur if the host does not recognize and reject the foreign transfused cells, and it can follow transfusion of any component that contains even very small numbers of viable T lymphocytes. Recipients with severe cellular immunodeficiency (except for HIV infection) are at greatest risk (eg, fetuses receiving intrauterine transfusions, recipients of hematopoietic progenitor cell transplants, and selected patients with severe immunodeficiency conditions), but TA-GVHD has also been reported in recipients receiving fludarabine for oncologic and rheumatologic diseases, and in immunologically normal recipients who are heterozygous for a tissue antigen haplotype for which the donor is homozygous. Tissue antigen haplotype sharing is most likely to occur when the transfused component is from a blood relative or has been selected for HLA compatibility. TA-GVHD remains a risk with leukocyte-reduced components because they contain sufficient residual T lymphocytes. Irradiation of the component renders T lymphocytes incapable of proliferation and is presently the only approved means to prevent TA-GVHD. Nonimmunologic Complications 1. Because whole blood and blood components are made from human blood, they may carry a risk of transmitting infectious agents [eg, viruses, bacteria, parasites, the variant CreutzfeldtJakob disease (vCJD) agent, and, theoretically, the classic CJD agent]. Careful donor selection and available laboratory tests do not totally eliminate the hazard. Also, septic and toxic reactions can result from transfusion of bacterially contaminated blood and blood components. Such reactions are infrequent, but may be life-threatening. This may occur despite careful selection of donors and testing of blood. Donor selection criteria are designed to screen out potential donors with increased risk of infection with HIV, HTLV, hepatitis, and syphilis, as well as other agents (see section on Testing of Donor Blood). These procedures do not totally eliminate the risk of transmitting these agents. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 98 of 290 6 2. 3. 4. Cytomegalovirus (CMV) may, unpredictably, be present in white-cell-containing components from donors previously infected with this virus, which can persist lifelong despite the presence of serum antibodies. Up to 70% of donors may be anti-CMV positive. Transmission of CMV by transfusion may be of concern in low-birthweight (≤1220 g) premature infants born to CMV-seronegative mothers and/or certain other categories of immunocompromised individuals, if they are CMV seronegative. For at-risk recipients, the risk of CMV transmission by cellular components can be reduced by transfusing CMVseronegative or leukocyte-reduced components. For other infectious agents (eg, Babesia spp, Leishmania spp, and Plasmodia spp) there are no routinely available tests to predict or prevent disease transmission. All potential blood donors are subjected to screening procedures intended to reduce to a minimum the risk that they will transmit infectious agents. Bacterial sepsis occurs rarely but can cause acute, severe, sometimes life-threatening effects. Onset of high fever (≥2 C or ≥3.5 F increase in temperature), severe chills, hypotension, or circulatory collapse during or shortly after transfusion should suggest the possibility of bacterial contamination and/or endotoxin reaction. Although platelet components stored at room temperature have been implicated most frequently, previously frozen components thawed by immersion in a waterbath and red cell components stored for several weeks at 1 to 6 C have also been implicated. Although most apheresis platelets are routinely tested for bacterial contamination, this does not completely eliminate the risk. Both gram-positive and gram-negative organisms have been identified as causing septic reactions. Organisms capable of multiplying at low temperatures (eg, Yersinia enterocolitica) and those using citrate as a nutrient are most often associated with components containing red cells. A variety of pathogens, as well as skin contaminants, have been found in platelet components. Endotoxemia in recipients has resulted from multiplication of gram-negative bacteria in blood components. Prompt recognition of a possible septic reaction is essential, with immediate discontinuation of the transfusion and aggressive therapy with broad-spectrum antimicrobials and vasopressor agents, if necessary. In addition to prompt sampling of the patient’s blood for cultures, investigation should include examination of material from the blood container by Gram’s stain, and cultures of specimens from the container and the administration set. It is important to report all febrile transfusion reactions to the transfusion service. Follow-through from the transfusion service to the blood collection facility may facilitate retrieval of other components associated with the collection. TACO, leading to pulmonary edema, can occur after transfusion of excessive volumes or at excessively rapid rates. This is a particular risk in the very young and the elderly and in patients with chronic severe anemia in whom low red cell mass is associated with high plasma volume. Small transfusion volumes can precipitate symptoms in at-risk patients who already have a positive fluid balance. Pulmonary edema should be promptly and aggressively treated, and infusion of colloid preparations, including plasma components and the suspending plasma in cellular components, reduced to a minimum. Hypothermia carries a risk of cardiac arrhythmia or cardiac arrest and exacerbation of coagulopathy. Rapid infusion of large volumes of cold blood or blood components can depress body temperature, and the danger is compounded in patients experiencing shock or surgical or anesthetic manipulations that disrupt temperature regulation. A blood warming device should be considered if rapid infusion of blood or blood components is needed. Warming must be accomplished using an FDA-cleared warming device so as not to cause hemolysis. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 99 of 290 7 5. Metabolic complications may accompany large-volume transfusions, especially in neonates and patients with liver or kidney disease. a. Citrate “toxicity” reflects a depression of ionized calcium caused by the presence in the circulation of large quantities of citrate anticoagulant. Because citrate is promptly metabolized by the liver, this complication is rare. Patients with severe liver disease or those with circulatory collapse that prevents adequate hepatic blood flow may have physiologically significant hypocalcemia after rapid, large-volume transfusion. Citrated blood or blood components administered rapidly through central intravenous access may reach the heart so rapidly that ventricular arrhythmias occur. Standard measurement of serum calcium does not distinguish ionized from complexed calcium. Ionized calcium testing or electrocardiogram monitoring is more helpful in detecting physiologically significant alteration in calcium levels. b. Other metabolic derangements can accompany rapid or large-volume transfusions, especially in patients with preexisting circulatory or metabolic problems. These include acidosis or alkalosis (deriving from changing concentrations of citric acid and its subsequent conversion to pyruvate and bicarbonate) and hyper- or hypokalemia. Fatal Transfusion Reactions When a fatality occurs as a result of a complication of blood or blood component transfusion, the Director, Office of Compliance and Biologics Quality, Center for Biologics Evaluation and Research (CBER), should be notified within 1 FDA business day (telephone: 301-827-6220; email: [email protected]). Within 7 days after the fatality, a written report must be submitted to the Director, Office of Compliance and Biologics Quality, HFM-600, CBER, FDA, 1401 Rockville Pike, Rockville, MD 20852-1448. A copy of the report should be sent to the collecting facility, if appropriate. Updated information about CBER reporting requirements may be found at http://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/ReportaProblem/ TransfusionDonationFatalities/default.htm. Components Containing Red Cells Overview Description Red cells contain hemoglobin and serve as the primary agent for transport of oxygen to tissues. The primary red-cell-containing transfusion component is Red Blood Cells (RBCs). This component is prepared by centrifugation or sedimentation of Whole Blood to remove much of the plasma. RBC components can also be prepared by apheresis methods. Depending upon the collection system used, a single whole blood donation typically contains either 450 mL (±10%) or 500 mL (±10%) of blood collected from blood donors with a minimum hematocrit of 38%, withdrawn in a sterile container that includes an anticoagulant solution licensed for this component. Occasionally, units of other volumes are collected and those volumes are stated on the label. Red-cell-containing components can be stored for an interval (“shelf life”) determined by the properties of the anticoagulant-preservative solution (see Table 1). Whole Blood units are prepared in an aseptic manner in a ratio of 14 mL of anticoagulant-preservative solution per 100 mL of whole blood collected. Apheresis components are collected into anticoagulants as recommended by the manufacturer. After plasma is removed, the resulting component is Red Blood Cells, which has a hematocrit of 65% to 80% and a usual volume between 225 mL and 350 mL. Additive solutions (AS) may For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 100 of 290 8 be mixed with the red cells remaining after removal of nearly all of the plasma (see Table 2). The typical hematocrit of AS RBCs is 55% to 65% and the volume is approximately 300 to 400 mL. AS RBCs have a shelf life of 42 days. Descriptions of specific components containing red cells are given at the end of this section. Table 1. Contents of Anticoagulant-Preservative Solutions Citric Acid Monobasic Sodium Phosphate Dextrose Adenine Shelf Life 8.0 g/L 0 24.5 g/L 0 21 days 26.3 g/L 3.27 g/L 2.22 g/L 25.5 g/L 0 21 days Citrate-phosphate-dextrose-dextrose (CP2D) 26.3 g/L 3.27 g/L 2.22 g/L 51.1 g/L 0 21 days Citrate-phosphate-dextrose-adenine (CPDA-1) 26.3 g/L 3.27 g/L 2.22 g/L 31.9 g/L 0.275 g/L 35 days Citric Acid Shelf Life Trisodium Citrate Anticoagulant citrate-dextrose A (ACD-A)* 22.0 g/L Citrate-phosphate dextrose (CPD) Anticoagulant-Preservative *ACD is used for apheresis components. Table 2. Content of Additive Solutions (in mg/100mL) Additive Solution (mg/100 mL) Monobasic Sodium Phosphate Mannitol Sodium Chloride 0 750 900 0 0 42 days 30 276 0 410 588 42 42 days 30 0 525 877 0 0 42 days Dextrose Adenine AS-1 (Adsol) 2200 27 AS-3 (Nutricel) 1100 AS-5 (Optisol) 900 Sodium Citrate Actions All RBC components and Whole Blood increase the recipient’s oxygen-carrying capacity by increasing the mass of circulating red cells. Processing and/or storage deplete the component of virtually all potential therapeutic benefit attributable to the functions of white cells and platelets; cellular elements remain in these blood components and may cause adverse immunologic or physiologic consequences. Residual plasma in the component provides the recipient with volume expansion and nonlabile plasma proteins to the extent that residual plasma is present in the preparation. Depending on the method of production, RBCs may contain approximately 20 to 100 mL of residual plasma. RBCs prepared with additive solutions are the most commonly used red cell product and have limited residual plasma. Indications Red-cell-containing components are indicated for treatment of symptomatic or critical deficit of oxygen-carrying capacity. They are also indicated for red cell exchange transfusion. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 101 of 290 9 Contraindications Red-cell-containing components should not be used to treat anemias that can be corrected with specific hematinic medications such as iron, vitamin B12, folic acid, or erythropoietin. RBCs or Whole Blood should not be used solely for volume expansion or to increase oncotic pressure of circulating blood. Dosage and Administration Each unit of RBCs or Whole Blood contains enough hemoglobin to increase the hemoglobin concentration in an average-sized adult by approximately 1 g/dL (increase hematocrit by 3%). Smaller aliquots can be made available for use with neonatal or pediatric patients, or adults with special transfusion needs. The ABO group of all red-cell-containing components must be compatible with ABO antibodies in the recipient’s plasma. Whole Blood must be ABO identical with the recipient; RBCs, which contain a reduced volume of antibody-containing plasma, need not be ABO identical. Serologic compatibility between recipient and donor must be established before any red-cellcontaining component is transfused. This may be accomplished by performing ABO/Rh typing, antibody screening, and crossmatching by serologic technique or use of a computer crossmatch. In cases when delay in transfusion will be life-threatening, uncrossmatched group O RBCs or ABO group-specific RBCs may be transfused before completion of pretransfusion compatibility testing. The initial portion of each unit transfused should be infused cautiously and with sufficient observation to detect onset of acute reactions. Thereafter, the rate of infusion can be more rapid, as tolerated by the patient’s circulatory system. It is undesirable for components that contain red cells to remain at room temperature longer than 4 hours. If the anticipated infusion rate must be so slow that the entire unit cannot be infused within 4 hours, it is appropriate to order smaller aliquots for transfusion. Side Effects and Hazards Hazards that pertain to all transfusion components are described in the earlier section titled Side Effects and Hazards for Whole Blood and All Blood Components. Listed below are hazards that apply specifically to components that contain red cells. 1. Hemolytic transfusion reaction is the immunologic destruction of transfused red cells, nearly always the result of incompatibility of antigen on the transfused cells with antibody in the recipient’s circulation (see item 5 below for discussion of nonimmunologic hemolysis). The most common cause of severe, acute hemolytic reactions is transfusion of ABOincompatible blood, resulting from identification errors occurring at some point(s) in the transfusion process. Serologic incompatibility undetected during pretransfusion testing is a much less common cause of acute hemolysis. If a transfusion reaction is suspected, the transfusion must be stopped and the transfusion service laboratory notified immediately. Information identifying the patient, the transfusion component, and associated forms and labels must be reviewed promptly to detect possible errors. A postreaction blood sample, preferably drawn from a site other than the transfusion access, must be sent to the laboratory along with the implicated unit of blood and administration set. Acute hemolytic reactions characteristically begin with an increase in temperature and pulse rate; symptoms may include chills, dyspnea, chest or back pain, abnormal bleeding, or shock. Instability of blood pressure is frequent, the direction and magnitude of change depending upon the phase of the reaction and the magnitude of compensatory mechanisms. In anesthetized patients, hemoglobinuria, hypotension, and evidence of disseminated intravascular coagulopathy (DIC) may be the first signs of incompatibility. Laboratory For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 102 of 290 10 2. 3. 4. 5. findings can include hemoglobinemia and/or hemoglobinuria, followed by elevation of serum bilirubin. The direct antiglobulin test (DAT) is usually positive, with rare exceptions (ie, complete hemolysis of incompatible red cells). Treatment includes measures to maintain or correct arterial blood pressure; correct coagulopathy, if present; and promote and maintain urine flow. Lack of symptoms does not exclude an acute hemolytic reaction. Delayed hemolytic reactions occur in previously red-cell-alloimmunized patients in whom antigens on transfused red cells provoke anamnestic production of antibody. The anamnestic response reaches a significant circulating level while the transfused cells are still present in the circulation; the usual time frame is 2 to 14 days after transfusion. Signs may include unexplained fever, development of a positive DAT, and unexplained decrease in hemoglobin/hematocrit. Hemoglobinemia and hemoglobinuria are uncommon, but elevation of lactate dehydrogenase (LDH) or bilirubin may be noted. Most delayed hemolytic reactions have a benign course and require no treatment. Hemolytic transfusion reactions in patients with sickle cell anemia may be particularly severe, with destruction of autologous as well as transfused red cells. In such patients, serologic investigations may not reveal the specificity of the causative antibody. Prospective matching for Rh and Kell antigens may decrease risk. Antigens on transfused red cells may cause red cell alloimmunization of the recipient. Clinically significant antibodies to red cell antigens will usually be detected in pretransfusion antibody screening tests. For most patients, red cell antigen matching beyond ABO and Rh is unnecessary. TACO, resulting in pulmonary edema, can accompany transfusion of any component at a rate more rapid than the recipient’s cardiac output can accommodate. Whole Blood creates more of a risk than Red Blood Cells because the transfused plasma adds volume without increasing oxygen-carrying capacity. Patients with chronic anemia have increased plasma volumes and are at increased risk for circulatory overload. Hemoglobinopathies is a long-term complication of repeated RBC transfusions. Each transfusion contributes approximately 250 mg of iron. Patients requiring multiple transfusions for aplastic anemia, thalassemias, or hemoglobinopathies are at far greater risk than patients transfused for hemorrhagic indications, because blood loss is an effective means of iron excretion. Patients with predictably chronic transfusion requirements should be considered for treatment with iron-chelating agents or a program of exchange transfusion therapy, if applicable. Nonimmunologic hemolysis occurs rarely, but can result from: 1) introduction of hypotonic fluids into the circulation, 2) effects of drugs co-administered with transfusion, 3) effects of bacterial toxins, 4) thermal injury to transfusion components, by either freezing or overheating, 5) metabolic damage to cells, as from hemoglobinopathies or enzyme deficiencies, or 6) development of physical or osmotic stresses. Examples of situations capable of causing nonimmune red cell hemolysis include: exposure to excessive heat by non-FDA-approved warming methods, mixture with hypotonic solutions, or transfusion under high pressure through small-gauge or defective needles. Components Available 1. RED BLOOD CELLS (RED BLOOD CELLS) are prepared from blood collected into any of the anticoagulant-preservative solutions approved by the FDA, and separated from the plasma by centrifugation or sedimentation. Separation may be done at any time during the allowable storage interval (“shelf life”). Red Blood Cells may contain from 160 to 275 mL of red cells (50-80 g of hemoglobin) suspended in varying quantities of residual plasma. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 103 of 290 11 2. 3. 4. 5. 6. 7. 8. 9. RED BLOOD CELLS ADENINE SALINE ADDED (RED BLOOD CELLS ADENINE SALINE ADDED) are prepared by centrifuging whole blood to remove as much plasma as possible, and replacing the plasma with usually 100 to 110 mL of an additive solution that contains some combination of dextrose, adenine, sodium chloride, and either monobasic sodium phosphate (AS-3) or mannitol (AS-1 and AS-5); the hematocrit is usually between 55% and 65%. Red Blood Cells in an additive solution have lower viscosity than Red Blood Cells, and flow through administration systems in a manner more comparable to that of Whole Blood. Red Blood Cells stored with an additive solution have an extended shelf life. RED BLOOD CELLS LEUKOCYTES REDUCED (RED BLOOD CELLS LEUKOCYTES REDUCED) are prepared from a unit of Whole Blood (collected in anticoagulant-preservative solution as noted above) containing ≥1 to 10 × 109 white cells. In general, leukocyte reduction is achieved by filtration: 1) soon after collection (prestorage) or 2) after varying periods of storage in the laboratory. Leukocyte reduction will decrease the cellular content and volume of blood according to characteristics of the filter system used. RBCs Leukocytes Reduced must have a residual content of leukocytes <5.0 × 106. Leukocyte reduction filters variably remove other cellular elements in addition to white cells. The leukocyte-reduced component contains at least 85% of the original red cell content. APHERESIS RED BLOOD CELLS (RED BLOOD CELLS PHERESIS) are red cells collected by apheresis. This component must be collected in an approved anticoagulant. The red cell volume collected and the anticoagulant used are noted on the label. Aside from the automated collection method used, the component is comparable to whole-blood-derived RBCs in all aspects. The dosage can be calculated, as for RBCs, from the red cell content of the product. Apheresis RBCs contain on average 60 g of hemoglobin per unit. APHERESIS RED BLOOD CELLS LEUKOCYTES REDUCED (RED BLOOD CELLS PHERESIS LEUKOCYTES REDUCED) are collected by apheresis methods. Leukocyte reduction is achieved in the manufacturing process resulting in a final product containing <5.0 × 106 leukocytes and at least 85% of the target red cell content. RED BLOOD CELLS, LOW VOLUME (RED BLOOD CELLS, LOW VOLUME) are products prepared when 300 to 404 mL of whole blood is collected into an anticoagulant volume calculated for 450 mL ± 45 mL or when 333 to 449 mL of whole blood is collected into an anticoagulant volume calculated for 500 mL ± 50 mL. These products reflect a collection with an altered ratio of anticoagulant to red cells and may not be an indication of a lower dose of hemoglobin. Plasma and platelet components should not be prepared from lowvolume collections. WHOLE BLOOD (WHOLE BLOOD) is rarely used for transfusion. In situations where Whole Blood is indicated but RBCs are used, a suitable plasma volume expander should be administered. See also General Information for Whole Blood and All Blood Components, Instructions for Use. All whole blood transfusions must be ABO identical. FROZEN RED BLOOD CELLS (RED BLOOD CELLS FROZEN) and FROZEN REJUVENATED RED BLOOD CELLS (RED BLOOD CELLS REJUVENATED FROZEN) are prepared by adding glycerol to red cells as a cryoprotective agent before freezing. The glycerol must be removed from the thawed component before it is infused. Frozen RBCs may be stored for up to 10 years, and for longer intervals if there is particular need for specific units. Ω Frozen storage is especially suitable for red cells with unusual antigenic phenotypes. DEGLYCEROLIZED RED BLOOD CELLS (RED BLOOD CELLS DEGLYCEROLIZED) is the form in which cryopreserved red cells (Frozen Red Blood Cells) are made available for infusion. Glycerol is added to red cells as a cryoprotective agent before freezing, and must be removed from the thawed component before it is infused. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 104 of 290 12 10. 11. 12. 13. Deglycerolized RBCs contain 80% or more of the red cells present in the original unit of blood, and have approximately the same expected posttransfusion survival as RBCs. Glycerol is removed by washing the cells with successively lower concentrations of Sodium Chloride, Injection (USP); the final suspension is in 0.9% Sodium Chloride, Injection (USP), with or without small amounts of dextrose. Small amounts of residual-free hemoglobin may cause the supernatant fluid to be pink-tinged. Deglycerolized RBCs provide the same physiologic benefits as RBCs, but their use is usually restricted to situations in which standard transfusion components are inappropriate or unavailable. Deglycerolized RBCs may be useful for transfusions to patients with previous severe allergic transfusion reactions, because the process efficiently removes plasma constituents. In addition to the side effects and hazards of RBC transfusion, Deglycerolized RBCs carry a risk of intravascular hemolysis if deglycerolization has been inadequate. Deglycerolized RBCs must be transfused within 24 hours after thawing if prepared in an open system. If prepared in a closed system, they can be infused within a 2-week interval after thawing. REJUVENATED RED BLOOD CELLS (RED BLOOD CELLS REJUVENATED) may be prepared from red cells stored in CPD, CPDA-1, and AS-1 storage solutions up to 3 days after expiration. Addition of an FDA-approved solution containing inosine, phosphate, and adenine restores 2,3-diphosphoglycerate and adenosine triphosphate to levels approximating those of freshly drawn cells. These products must be washed before infusion to remove the inosine, which may be toxic. Rejuvenated RBCs may be prepared and transfused within 24 hours or frozen for long-term storage. DEGLYCEROLIZED REJUVENATED RED BLOOD CELLS (RED BLOOD CELLS REJUVENATED DEGLYCEROLIZED) is the form in which rejuvenated, cryopreserved red cells (Frozen Rejuvenated Red Blood Cells) are made available for infusion. For additional information, see sections on Rejuvenated RBCs and Deglycerolized RBCs above. Autologous Whole Blood and RBCs are drawn from patients who anticipate requiring blood transfusions. Donor-safety screening criteria and testing procedures applicable to collection from allogeneic donors do not always apply to these components. Each unit must be labeled “FOR AUTOLOGOUS USE ONLY.” A biohazard label is required if these units have a reactive test result. In addition, if these units are untested, they must be labeled as “DONOR UNTESTED.” Autologous Whole Blood or RBCs can be modified into any of the components described above. If a facility allows for autologous units to be crossed over for inclusion in the general blood inventory, the donors and units must be subjected to the same donor eligibility requirements and test requirements as allogeneic donors and units. See section on Further Processing for irradiated products. Plasma Components Overview Plasma is the aqueous part of blood and can be derived from the separation of a whole-blood collection or by apheresis collection. Important elements in plasma include albumin, coagulation factors, fibrinolytic proteins, immunoglobulin, and other proteins. Once plasma is collected, it can be stored frozen and subsequently thawed and kept in a liquid state. If Fresh Frozen Plasma (FFP) is thawed at 1 to 6 C, and the insoluble cryoprecipitate (see Cryoprecipitated Components) is removed by centrifugation, the supernatant plasma can be refrozen and labeled as Plasma Cryoprecipitate Reduced. Labile coagulation factor levels vary based upon ABO group, storage conditions, and/or further processing (see Table 3). For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 105 of 290 13 Table 3. Coagulation Factor Activity of Thawed Plasma Derived from FFP* Level† Day 1 Day 2 Day 3 Day 4 Day 5 Mean Change from Day 1 to Day 5 (%) 107 ± 26 103 ± 44 70 ± 16 81 ± 9 79 ± 7 90 ± 18 85 ± 13 225 ± 12 76 ± 19 74 ± 37 51 ± 10 81 ± 9 75 ± 8 81 ± 15 84 ± 13 224 ± 13 66 ± 18 71 ± 35 43 ± 10 81 ± 9 71 ± 9 76 ± 15 84 ± 15 224 ± 13 65 ± 17 67 ± 36 43 ± 7 80 ± 10 68 ± 9 72 ± 14 82 ± 11 224 ± 17 63 ± 16 67 ± 33 41 ± 8 80 ± 10 66 ± 9 72 ± 15 80 ± 11 225 ± 12 41 35 41 1 16 20 6 0 Coagulation Factor Factor VIII (%) Blood group A Blood group B Blood group O Factor II (%) Factor V (%) Factor VII (%) Factor X Fibrinogen (mg/dL) p Values <0.004‡ <0.02‡ <0.001‡ NS NS NS NS NS *Reported with permission from Downes KA, Wilson E, Yomtovian R, Sarode R. Serial measurement of clotting factors in thawed plasma for 5 days (letter). Transfusion 2001;41:570. † Mean ± SD. ‡ Comparison of Factor VIII activity at Day 1 and that at Day 3 was statistically significant. Fresh Frozen Plasma Description FRESH FROZEN PLASMA (FRESH FROZEN PLASMA) is prepared from a whole blood or apheresis collection and frozen at –18 C or colder within the time frame as specified in the directions for use for the blood collection, processing, and storage system. The anticoagulant solution used and the component volume are indicated on the label. On average, units contain 200 to 250 mL, but apheresis-derived units may contain as much as 400 to 600 mL. FFP contains plasma proteins including all coagulation factors. FFP contains high levels of the labile coagulation Factors V and VIII. FFP should be infused immediately after thawing or stored at 1 to 6 C for up to 24 hours. If stored longer than 24 hours, the component must be relabeled (see Thawed Plasma) or discarded depending on the method of collection. Action FFP serves as a source of plasma proteins for patients who are deficient in or have defective plasma proteins. Indications FFP is indicated in the following conditions: 1. Management of preoperative or bleeding patients who require replacement of multiple plasma coagulation factors (eg, liver disease, DIC). 2. Patients undergoing massive transfusion who have clinically significant coagulation deficiencies. 3. Patients taking warfarin who are bleeding or need to undergo an invasive procedure before vitamin K could reverse the warfarin effect or who need only transient reversal of warfarin effect. 4. For transfusion or plasma exchange in patients with thrombotic thrombocytopenic purpura (TTP). For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 106 of 290 14 5. 6. Management of patients with selected coagulation factor deficiencies, congenital or acquired, for which no specific coagulation concentrates are available. Management of patients with rare specific plasma protein deficiencies, such as C1 inhibitor, when recombinant products are unavailable. Contraindications Do not use this product when coagulopathy can be corrected more effectively with specific therapy, such as vitamin K, Cryoprecipitated AHF (Antihemophilic Factor), or specific coagulation factor concentrates. Do not use this product when blood volume can be safely and adequately replaced with other volume expanders. Dosage and Administration Compatibility tests before transfusion are not necessary. Plasma must be ABO compatible with the recipient’s red cells. The volume transfused depends on the clinical situation and patient size, and may be guided by laboratory assays of coagulation function. Do not use FFP if there is evidence of container breakage or of thawing during storage. FFP must be thawed in a waterbath at 30 to 37 C or in an FDA-cleared device. If a waterbath is used, thaw the component in a protective plastic overwrap using gentle agitation. Side Effects and Hazards Hazards that pertain to all transfusion components, including FFP, are described in the earlier section on Side Effects and Hazards for Whole Blood and All Blood Components. Plasma Frozen Within 24 Hours After Phlebotomy Description PLASMA FROZEN WITHIN 24 HOURS AFTER PHLEBOTOMY (PLASMA FROZEN WITHIN 24 HOURS AFTER PHLEBOTOMY) is prepared from a whole blood collection and must be separated and placed at –18 C or below within 24 hours from whole blood collection. The anticoagulant solution used and the component volume are indicated on the label. On average, units contain 200 to 250 mL. This plasma component is a source of nonlabile plasma proteins. Levels of Factor VIII are significantly reduced and levels of Factor V and other labile plasma proteins are variable compared with FFP. Plasma Frozen Within 24 Hours After Phlebotomy should be infused immediately after thawing or stored at 1 to 6 C for up to 24 hours. If stored longer than 24 hours, the component must be relabeled (see Thawed Plasma) or discarded. Action This plasma component serves as a source of plasma proteins for patients who are deficient in or have defective plasma proteins. Coagulation factor levels might be lower than those of FFP, especially labile coagulation Factors VIII and V. Indications See Fresh Frozen Plasma. Contraindications See Fresh Frozen Plasma. In addition, this product is not indicated for treatment of deficiencies of labile coagulation factors including Factors VIII and V. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 107 of 290 15 Dosage and Administration See Fresh Frozen Plasma. Side Effects and Hazards See Fresh Frozen Plasma. Plasma Cryoprecipitate Reduced Description PLASMA CRYOPRECIPITATE REDUCED (PLASMA, CRYOPRECIPITATE REDUCED) is prepared from FFP after thawing and centrifugation and removal of the cryoprecipitate. The remaining product is plasma that is deficient in fibrinogen, Factor VIII, Factor XIII, von Willebrand factor (vWF), cryoglobulin, and fibronectin. This supernatant plasma must be refrozen within 24 hours. Proteins such as albumin; ADAMTS13; and Factors II, V, VII, IX, X, and XI remain in almost the same levels as in FFP [the high-molecular-weight forms of vWF (multimers) are more thoroughly removed by this process than smaller multimers]. Action This component serves as a source for plasma proteins except for fibrinogen, Factor VIII, Factor XIII, and vWF. Indications Plasma Cryoprecipitate Reduced is used for transfusion or plasma exchange in patients with TTP. It may be used to provide clotting factors except fibrinogen, Factor VIII, Factor XIII, and vWF. Contraindications This component should not be used as a substitute for FFP, Plasma Frozen Within 24 Hours After Phlebotomy, or Thawed Plasma. Dosage and Administration See Fresh Frozen Plasma. Side Effects and Hazards See Fresh Frozen Plasma. Liquid Plasma Components Description Other plasma components may be made from whole blood collected in all approved anticoagulants. Levels and activation state of coagulation proteins in these products are variable. The volume is indicated on the label. THAWED PLASMA Ω (THAWED PLASMA) is derived from FFP or Plasma Frozen Within 24 Hours After Phlebotomy, prepared using aseptic techniques (closed system), thawed at 30 to 37 C, and maintained at 1 to 6 C for up to 4 days after the initial 24-hour post-thaw period has elapsed. The volume is indicated on the label. Thawed Plasma contains stable coagulation factors such as Factor II and fibrinogen in concentrations similar to those of FFP, but variably reduced amounts of other factors (see Table 3). For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 108 of 290 16 Action This component serves as a source of plasma proteins. Levels and activation state of coagulation proteins in thawed plasma are variable and change over time. Indications 1. Management of preoperative or bleeding patients who require replacement of multiple plasma coagulation factors except for patients with a consumptive coagulopathy. 2. Initial treatment of patients undergoing massive transfusion who have clinically significant coagulation deficiencies. 3. Patients taking warfarin who are bleeding or need to undergo an invasive procedure before vitamin K could reverse the warfarin effect or who need only transient reversal of warfarin effect. This component should not be used to treat isolated coagulation factor deficiencies where other products are available with higher concentrations of the specific factor(s). Contraindications See Fresh Frozen Plasma. Do not use liquid plasma components as the treatment for isolated coagulation factor deficiencies where other products are available with higher concentrations of the specific factor(s). Dosage and Administration See Fresh Frozen Plasma. Side Effects and Hazards See Fresh Frozen Plasma. LIQUID PLASMA (LIQUID PLASMA) is separated no later than 5 days after the expiration date of the Whole Blood and is stored at 1 to 6 C. The profile of plasma proteins in Liquid Plasma is poorly characterized. Levels and activation state of coagulation proteins in Liquid Plasma are dependent upon and change with time in contact with cells, as well as the conditions and duration of storage. Action This component serves as a source of plasma proteins. Levels and activation state of coagulation proteins are variable and change over time. Indications Initial treatment of patients who are undergoing massive transfusion because of life-threatening trauma/hemorrhages and who have clinically significant coagulation deficiencies. Contraindications See Fresh Frozen Plasma. Do not use liquid plasma components as the treatment for isolated coagulation factor deficiencies where other products are available with higher concentrations of the specific factor(s). Dosage and Administration See Fresh Frozen Plasma. Side Effects and Hazards See Fresh Frozen Plasma. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 109 of 290 17 Cryoprecipitated Components Overview Description Cryoprecipitated Antihemophilic Factor (AHF) is prepared by thawing whole-blood-derived FFP between 1 and 6 C and recovering the precipitate. The cold-insoluble precipitate is refrozen within 1 hour. Cryoprecipitated AHF contains fibrinogen, Factor VIII, Factor XIII, vWF, and fibronectin. Each unit of Cryoprecipitated AHF should contain ≥80 IU Factor VIII units and ≥150 mg of fibrinogen in approximately 5 to 20 mL of plasma. If the label indicates “Pooled Cryoprecipitated AHF,” several units of Cryoprecipitated AHF have been pooled. The volume of the pool is indicated on the label and, if used, the volume of 0.9% Sodium Chloride, Injection (USP) added may be separately listed. To determine the minimum potency of this component, assume 80 IU of Factor VIII and 150 mg of fibrinogen for each unit of Cryoprecipitated AHF indicated on the label. Action Cryoprecipitate serves as a source of fibrinogen, Factor VIII, Factor XIII, vWF, and fibronectin. Indications This component is used in the control of bleeding associated with fibrinogen deficiency and to treat Factor XIII deficiency. It is also indicated as second-line therapy for von Willebrand disease and hemophilia A (Factor VIII deficiency). Coagulation factor preparations other than cryoprecipitate are preferred when blood component therapy is needed for management of von Willebrand disease and Factor VIII deficiency. Use of this component may be considered for control of uremic bleeding after other modalities have failed. Indications for use as a source of fibronectin are not clear. Contraindications Do not use this component unless results of laboratory studies indicate a specific hemostatic defect for which this product is indicated. Cryoprecipitate should not be used if virus-inactivated Factor VIII concentrates or recombinant factor preparations are available for management of patients with von Willebrand disease or hemophilia A. Dosage and Administration Compatibility testing is unnecessary. ABO-compatible material is preferred. Rh type need not be considered when using this component. The frozen component is thawed in a protective plastic overwrap in a waterbath at 30 to 37 C up to 15 minutes (thawing time may need to be extended if product is pooled before freezing). This component should not be given if there is evidence of container breakage or of thawing during storage. Do not refreeze after thawing. Thawed Cryoprecipitated AHF should be kept at room temperature and transfused as soon as possible after thawing, within 6 hours if it is a single unit (from individual donor, or pooled before freezing or administration using an FDA-cleared sterile connecting device), and within 4 hours after entering the container (eg, to attach an administration set or to pool) without using an FDA-cleared sterile connecting device. Cryoprecipitated AHF may be transfused as individual units or pooled. For pooling, the precipitate in one or more concentrates should be mixed well with 10 to 15 mL of diluent to ensure complete removal of all material from the container. The preferred diluent is 0.9% For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 110 of 290 18 Sodium Chloride, Injection (USP). Serial use of each bag’s contents to resuspend the precipitate into subsequent bags may be used to efficiently pool cryoprecipitate into a single bag. The recovery of transfused fibrinogen is 50% to 60%. When used to correct hypofibrinogenemia, Cryoprecipitated AHF may be dosed according to the following formula to raise plasma fibrinogen by approximately 50 to 100 mg/dL: Number of bags = 0.2 × body weight in kg. Thrombosis alters fibrinogen kinetics; therefore, patients receiving cryoprecipitate as fibrinogen replacement in conditions associated with increased fibrinogen turnover should be monitored with fibrinogen assays. For treatment of bleeding in patients with hemophilia A when Factor VIII concentrates are not available, rapid infusion of a loading dose expected to produce the desired level of Factor VIII is usually followed by a smaller maintenance dose every 8 to 12 hours. To maintain hemostasis after surgery, a regimen of therapy for 10 days or longer may be required. If circulating antibodies to Factor VIII are present, the use of larger doses, activated concentrates, porcinederived concentrates, or other special measures may be indicated. To calculate cryoprecipitate dosage as a source of Factor VIII, the following formula is helpful: Number of bags = (Desired increase in Factor VIII level in % × 40 × body weight in kg) / average units of Factor VIII per bag, minimum 80. Good patient management requires that the Cryoprecipitated AHF treatment responses of Factor VIII-deficient recipients be monitored with periodic plasma Factor VIII assays. For treatment of von Willebrand disease, smaller amounts of Cryoprecipitated AHF will correct the bleeding time. Because the vWF content of Cryoprecipitated AHF is not usually known, an empiric dose of 1 bag per 10 kg of body weight has been recommended. These patients should be monitored by appropriate laboratory studies to determine the frequency of Cryoprecipitated AHF administration. Side Effects and Hazards Hazards that pertain to all transfusion components are described in the earlier section on Side Effects and Hazards for Whole Blood and All Blood Components. If a large volume of ABO-incompatible cryoprecipitate is used, the recipient may develop a positive DAT and, very rarely, mild hemolysis. Components Available 1. CRYOPRECIPITATED AHF (CRYOPRECIPITATED AHF) 2. POOLED CRYOPRECIPITATED AHF (CRYOPRECIPITATED AHF, POOLED) Platelet Components Overview Description Platelet therapy may be achieved by infusion of either Apheresis Platelets or Platelets (wholeblood-derived platelet concentrates). In either component, platelets are suspended in an appropriate volume of the original plasma, which contains near-normal levels of stable coagulation factors that are stored at room temperature. One unit of Platelets derived from a whole blood collection usually contains no fewer than 5.5 × 1010 platelets suspended in 40 to 70 mL of plasma. Platelets may be provided either singly or as a pool. One unit of Apheresis Platelets usually contains ≥3.0 × 1011 platelets and is a therapeutic equivalent to 4 to 6 units of For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 111 of 290 19 Platelets. Platelet components may contain a varying number of leukocytes depending upon the technique used in preparation. Some units may contain more than the trace amounts of red cells usually present and will appear pink to salmon in color. Actions Platelets are essential for normal hemostasis. Complex reactions occur between platelets, vWF, collagen in the walls of disturbed vasculature, phospholipids, and soluble coagulation factors, including thrombin. These changes induce platelet adherence to vessel walls and platelet activation, which leads to platelet aggregation and formation of a primary hemostatic plug. The therapeutic goal of platelet transfusion is to provide adequate numbers of normally functioning platelets for the prevention or cessation of bleeding. Indications Platelet transfusions may be given to patients with thrombocytopenia, dysfunctional platelet disorders, active platelet-related bleeding, or serious risk of bleeding (ie, prophylactic use). Patients with the following medical conditions may require platelet transfusion: leukemia, myelodysplasia, aplastic anemia, solid tumors, congenital or acquired platelet dysfunction, central nervous system trauma. Patients undergoing extracorporeal membrane oxygenation or cardiopulmonary bypass may also need platelet transfusion. Thrombocytopenia is unlikely to be the cause of bleeding in patients with platelet counts of at least 50,000/μL. Higher transfusion thresholds may be appropriate for patients with platelet dysfunction. For the clinically stable patient with an intact vascular system and normal platelet function, prophylactic platelet transfusions may be appropriate at 5000 to 10,000/μL. Prophylactic platelet transfusion may not be of therapeutic benefit when thrombocytopenia is related to destruction of circulating platelets secondary to autoimmune disorders [eg, immune thrombocytopenic purpura (ITP)]; however, when these patients bleed, platelet therapy is often useful. Platelets Leukocytes Reduced or Apheresis Platelets Leukocytes Reduced are indicated to decrease the frequency of recurrent febrile, nonhemolytic transfusion reaction, HLA alloimmunization, and transfusion-transmitted CMV infection (see section on Further Processing). Contraindications Do not use this component if bleeding is unrelated to decreased numbers of, or abnormally functioning, platelets. If platelet function is normal, platelets should not be transfused when the platelet count is greater than 100,000/μL. Prophylactic transfusion is generally not indicated when platelet dysfunction is extrinsic to the platelet, such as in uremia, certain types of von Willebrand disease, and hyperglobulinemia. Patients with congenital surface glycoprotein(s) defects should be transfused conservatively to reduce the possibility for alloimmunization to the missing protein(s). Do not use in patients with activation or autoimmune destruction of endogenous platelets, such as in heparin-induced thrombocytopenia (HIT), TTP, or ITP, unless the patient has a lifethreatening hemorrhage. Dosage and Administration Compatibility testing is not necessary in routine platelet transfusion. Except in unusual circumstances, the donor plasma should be ABO compatible with the recipient’s red cells when this component is to be transfused to infants or when large volumes are to be transfused. The number of platelet units to be administered depends on the clinical situation of each patient. One unit of Platelets would be expected to increase the platelet count of a 70-kg adult by 5000 to For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 112 of 290 20 10,000/μL and increase the count of an 18-kg child by 20,000/μL. The therapeutic adult dose is 1 unit of Apheresis Platelets or 4 to 6 units of whole-blood-derived platelets, either of which usually contain ≥3.0 × 1011 platelets. For prophylaxis, this dose may need to be repeated in 1 to 3 days because of the short lifespan of transfused platelets (3-4 days). Platelet components must be examined before administration. Units with excessive aggregates should not be administered. Transfusion may proceed as quickly as tolerated, but must take less than 4 hours. Do not refrigerate platelets. The corrected count increment (CCI) is a calculated measure of patient response to platelet transfusion that adjusts for the number of platelets infused and the size of the recipient, based upon body surface area (BSA) CCI = (post-count – pre-count) × BSA / platelets transfused where post-count and pre-count are platelet counts (/μL) after and before transfusion, 2 respectively; BSA is the patient body surface area (meter ); and platelets transfused is the number of administered platelets (× 1011). The CCI is usually determined 10 to 60 minutes after transfusion. For example: 2 A patient with acute myelogenous leukemia with a nomogram-derived BSA of 1.40 meter is 11 transfused with a unit of Apheresis Platelets (a platelet dose of 4.5 × 10 ). The pretransfusion platelet count is 2000/μL. The patient’s platelet count from a sample of blood collected 15 minutes after platelet transfusion is 29,000/μL. The CCI is calculated as (29,000 – 2000) × 1.4 / 11 2 4.5 = 8,400/μL per 10 per m . In the clinically stable patient, the CCI is typically greater than 7500 at 10 minutes to 1 hour after transfusion and remains above 4500 at 24 hours. Both immune and nonimmune mechanisms may contribute to reduced platelet recovery and survival. Along with supportive serologic test results, a CCI of less than 5000 at 10 minutes to 1 hour after transfusion may indicate an immune-mediated refractory state to platelet therapy. With nonimmune mechanisms, platelet recovery within 1 hour may be adequate, although survival at 24 hours is reduced (refer to Platelet Alloimmunization). Side Effects and Hazards Hazards that pertain to all transfusion components are described in the section on Side Effects and Hazards for Whole Blood and All Blood Components. Listed below are hazards that apply specifically to components that contain platelets. 1. Bacterial Contamination: Although methods to limit and detect bacterial contamination have been implemented for most platelet components, they remain the most likely blood components to be contaminated with bacteria. Gram-positive skin flora are the most commonly recovered bacteria. Symptoms may include high fever (≥2.0 C or ≥3.5 F increase in temperature), severe chills, hypotension, or circulatory collapse during or immediately after transfusion. In some instances, symptoms, especially when associated with contamination by gram-positive organisms, may be delayed for several hours following transfusion. Prompt management should include broad-spectrum antibiotic therapy along with cultures from the patient, suspected blood component(s), and administration set. A Gram’s stain of suspected contaminated unit(s) should be performed whenever possible. Apheresis Platelets are usually tested for bacterial contamination before issue. 2. Platelet Alloimmunization: Platelets bear a variety of antigens, including HLA and plateletspecific antigens. Patients transfused with platelets often develop HLA antibodies. The patient may become refractory to incompatible platelets. When platelets are transfused to a patient with an antibody specific for an expressed antigen, the survival time of the transfused For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 113 of 290 21 3. 4. platelets may be markedly shortened. Nonimmune events may also contribute to reduced platelet survival. It is possible to distinguish between immune and nonimmune platelet refractoriness by assessing platelet recovery soon after infusion (ie, a 10- to 60-minute postinfusion platelet increment). In immune refractory states secondary to serologic incompatibility, there is poor recovery in the early postinfusion interval. In nonimmune mechanisms (ie, splenomegaly, sepsis, fever, intravascular devices, and DIC) platelet recovery within 1 hour of infusion may be adequate while longer-term survival (ie, 24-hour survival) is reduced. Serologic tests may confirm the presence of alloimmunization. Serologic tests (HLA typing or a platelet crossmatch) may also be helpful in selecting platelets with acceptable survival. Red Blood Cell Alloimmunization: Immunization to red cell antigens may occur because of the presence of residual red cells in Platelets. Red cell compatibility testing is necessary only if the component is prepared by a method that allows the component to contain 2 mL or more of red cells, making the unit appear pink to salmon in color. When platelet components from Rh-positive donors must be given to Rh-negative females of childbearing potential because of lack of availability of Rh-negative platelets, prevention of D immunization by use of Rh Immune Globulin should be considered. Hemolysis: Platelet transfusions that are not ABO identical may contain incompatible plasma and may cause a positive DAT and possibly, hemolysis. Platelet transfusions from group O donors with high-titer isohemagglutinins (anti-A or anti-B) may cause acute hemolytic reactions in susceptible patients. Components Available 1. PLATELETS (PLATELETS) are a concentrate of platelets separated from a single unit of Whole Blood. One unit of Platelets should contain no fewer than 5.5 × 1010 platelets suspended in 40 to 70 mL of plasma. This component is usually provided as a pool. See below. 2. POOLED PLATELETS (PLATELETS POOLED) are composed of individual platelet units combined by aseptic technique and have an allowable shelf life as specified in the directions for use for the blood collection, processing, and storage system. The number of units of Platelets in the pool will be indicated on the label. To determine the minimum potency of this component, assume 5.5 × 1010 platelets per unit of Platelets indicated on the label. See the label for the approximate volume. 3. PLATELETS LEUKOCYTES REDUCED (PLATELETS LEUKOCYTES REDUCED) may be prepared using an open or closed system. One unit of Platelets Leukocytes Reduced should 10 5 contain 5.5 × 10 platelets and <8.3 × 10 leukocytes. Components prepared using an open system will expire 4 hours after preparation. Components prepared using a closed system will have a shelf life as specified in the directions for use for the blood collection, processing, and storage system. This component is usually provided as a pool. See below. 4. POOLED PLATELETS LEUKOCYTES REDUCED (PLATELETS LEUKOCYTES REDUCED, POOLED) may be prepared by pooling and filtering Platelets or pooling Platelets Leukocytes Reduced in an open system that will have a 4-hour shelf life. The number of units in the pool will be indicated on the label. To determine the minimum potency of this 10 component, assume 5.5 × 10 platelets per unit of Platelets Leukocytes Reduced indicated on the label and <5 × 106 leukocytes in the pool. See the label for the approximate volume. This component can also be prepared and pooled using an FDA-cleared system to provide a product with a 5-day shelf life. Components prepared using this system provide a therapeutic adult dose of platelets and <5.0 × 106 leukocytes. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 114 of 290 22 5. 6. APHERESIS PLATELETS (PLATELETS PHERESIS) are an effective way to harvest a therapeutic adult dose of platelets from a single donor. Apheresis Platelets should contain 11 ≥3.0 × 10 platelets. One unit of Apheresis Platelets may replace 4 to 6 units of Platelets. The volume of plasma is indicated on the label and varies between 100 and 500 mL. The number of leukocytes contained in this component varies depending upon the blood cell separator and protocol used for collection. Apheresis Platelets are supplied in one bag or in two connected bags to improve platelet viability during storage by providing more surface area for gas exchange. ACD-A is the anticoagulant solution currently used for the collection and preservation of Apheresis Platelets. APHERESIS PLATELETS LEUKOCYTES REDUCED (PLATELETS PHERESIS LEUKOCYTES REDUCED) can be leukocyte reduced during the collection process or may be prepared by further processing using leukocyte reduction filters. Apheresis Platelets Leukocytes Reduced should contain ≥3.0 × 1011 platelets and <5.0 × 106 leukocytes. When Apheresis Platelets Leukocytes Reduced are prepared by further processing, these may be labeled Apheresis Platelets Leukocytes Reduced provided the requirement for residual leukocyte count is met and the platelet recovery is at least 85% of the prefiltration content. The volume, anticoagulant-preservative, and storage conditions for Apheresis Platelets Leukocytes Reduced are the same as those for Apheresis Platelets. Apheresis Platelets Leukocytes Reduced have a shelf life of 5 days, unless the facility is participating in a postmarketing program, which allows a 7-day expiration date. Granulocyte Components Description APHERESIS GRANULOCYTES Ω (GRANULOCYTES PHERESIS) contain numerous leukocytes and platelets as well as 20 to 50 mL of red cells. The number of granulocytes in each concentrate is usually >1.0 × 1010. Various modalities may be used to improve granulocyte harvest, including donor administration of granulocyte colony-stimulating factor and/or corticosteroids. The final volume of the product is 200 to 300 mL including anticoagulant and plasma as indicated on the label. Red cell sedimenting agents approved by the FDA, such as hydroxyethyl starch (HES), are typically used in the collection of granulocytes. Residual agents will be present in the final component and are described on the label. Apheresis Granulocytes should be administered as soon after collection as possible because of well-documented deterioration of granulocyte function during short-term storage. If stored, maintain at 20 to 24 C without agitation for no more than 24 hours. Actions Granulocytes migrate toward, phagocytize, and kill bacteria and fungi. A quantitative relationship exists between the level of circulating granulocytes and the prevalence of bacterial and fungal infection in neutropenic patients. The ultimate goal is to provide the patient with the ability to fight infection. The infusion of a granulocyte component may not be associated with a significant increase in the patient’s granulocyte count and is dependent on multiple factors, including the patient’s clinical condition. Indications Granulocyte transfusion therapy is controversial. Apheresis Granulocytes are typically used in the treatment of patients with documented infections (especially gram-negative bacteria and For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 115 of 290 23 fungi) unresponsive to antimicrobial therapy in the setting of neutropenia [absolute granulocyte count <0.5 × 109/L (500/μL)] with expected eventual marrow recovery, or neonatal sepsis. A trial of broad-spectrum antimicrobial agents should be used before granulocyte transfusion therapy is initiated. If the intended recipient is CMV-seronegative and severely immunosuppressed (eg, a marrow transplant recipient), serious consideration should be given before administration of CMV-seropositive granulocytes. In addition to neutropenic patients, patients with hereditary neutrophil function defects (such as chronic granulomatous disease) may be candidates for granulocyte transfusion therapy. Contraindications Prophylactic use of granulocytes in noninfected patients is not routinely recommended. Dosage and Administration Transfuse as soon as possible. A standard blood infusion set is to be used for the administration of Apheresis Granulocytes. Do not administer using leukocyte reduction filters. Depth-type microaggregate filters and leukocyte reduction filters remove granulocytes. The red cells in Apheresis Granulocytes must be ABO compatible. Once granulocyte transfusion therapy is initiated, support should continue at least daily until infection is cured, 9 defervescence occurs, the absolute granulocyte count returns to at least 0.5 × 10 /L (500/μL), or the physician in charge decides to halt the therapy. Because most patients receiving these products are severely immunosuppressed, Apheresis Granulocytes are usually irradiated to prevent TA-GVHD (see section on Further Processing). Side Effects and Hazards Hazards that pertain to all transfusion components are described in the section on Side Effects and Hazards for Whole Blood and All Blood Components. Listed below are hazards that apply specifically to Apheresis Granulocytes. 1. Febrile Nonhemolytic Reactions: These reactions are frequently noted in patients receiving granulocyte transfusions. Fever and chills in patients receiving granulocyte components may be avoided or mitigated by slow administration and recipient premedication. 2. Allergic Reactions: Allergic reactions to HES and other red cell sedimenting solutions may occur during granulocyte transfusion. 3. Pulmonary Reactions: Granulocyte transfusion can cause worsening of pulmonary function in patients with pneumonia, and rarely severe pulmonary reactions, especially in patients receiving concomitant amphotericin B. 4. Alloimmunization: Immunization to HLA antigens frequently occurs with granulocyte transfusion and can cause refractoriness to platelet transfusion. Further Processing This section addresses further processing of previously described blood components. The processes described in this section are: Leukocyte reduction, identification of CMV-seronegative components, irradiation, and washing. A component may undergo one or more of these processes. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 116 of 290 24 Leukocyte Reduction Description A unit of whole blood generally contains ≥1 to 10 × 109 white cells. Leukocyte reduction may be achieved by in-process collection or filtration: 1) soon after collection (prestorage), 2) after varying periods of storage in the laboratory, or 3) at the bedside. The method used in the laboratory for leukocyte reduction is subject to quality control testing; leukocyte-reduced components prepared at the bedside are not routinely subjected to quality control testing. Leukocyte reduction will decrease the cellular content and volume of blood according to characteristics of the filter system used. Red Blood Cells Leukocytes Reduced, Apheresis Red Blood Cells Leukocytes Reduced, and Apheresis Platelets Leukocytes Reduced must have a residual content of leukocytes <5.0 × 106 and Platelets Leukocytes Reduced must have <8.3 × 105 residual leukocytes. Leukocyte reduction filters variably remove other cellular elements in addition to white cells. Washing is not a substitute for leukocyte reduction. Leukocyte reduction is not a substitute for irradiation. Indications Leukocyte-reduced components are indicated to decrease the frequency of recurrent febrile nonhemolytic transfusion reactions. They have also been shown to reduce the risk of transfusiontransmitted CMV and to reduce the incidence of HLA alloimmunization. Contraindications Leukocyte-reduced components do not prevent TA-GVHD. Leukocyte reduction filters are not to be used in the administration of Apheresis Granulocytes or Apheresis Granulocytes/Platelets. Side Effects and Hazards The use of blood components that are leukocyte reduced at the bedside may cause unexpected severe hypotension in some recipients, particularly those taking angiotensin converting enzyme inhibitor medication. Specific Leukocyte-Reduced Components RED BLOOD CELLS LEUKOCYTES REDUCED (RED BLOOD CELLS LEUKOCYTES REDUCED) APHERESIS RED BLOOD CELLS LEUKOCYTES REDUCED (RED BLOOD CELLS PHERESIS LEUKOCYTES REDUCED) PLATELETS LEUKOCYTES REDUCED (PLATELETS LEUKOCYTES REDUCED) APHERESIS PLATELETS LEUKOCYTES REDUCED (PLATELETS PHERESIS LEUKOCYTES REDUCED) Further Testing to Identify CMV-Seronegative Blood Description CMV-seronegative blood is selected by performing testing for antibodies to CMV. Transmission of CMV disease is associated with cellular blood components. Plasma, cryoprecipitate, and other plasma-derived blood components do not transmit CMV; therefore, CMV testing is not required for these components. Indications Transfusion of CMV-negative blood is indicated in CMV-seronegative recipients who are at risk for severe CMV infections. These at-risk groups include pregnant women and their fetuses, low For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 117 of 290 25 birthweight infants, hematopoietic progenitor cell transplant recipients, solid-organ transplant recipients, severely immunosuppressed recipients, and HIV-infected patients. Leukocyte-reduced components may be an alternative to CMV-seronegative transfusion in some clinical conditions. Irradiation Description Blood components that contain viable lymphocytes may be irradiated to prevent proliferation of T lymphocytes, which is the immediate cause of TA-GVHD. Irradiated blood is prepared by exposing the component to a radiation source. The standard dose of gamma irradiation is 2500 cGy targeted to the central portion of the container with a minimum dose of 1500 cGy delivered to any part of the component. Indications Irradiated cellular components are indicated for use in patient groups that are at risk for TAGVHD from transfusion. At-risk groups include: fetal and neonatal recipients of intrauterine transfusions, selected immunocompromised recipients, recipients of cellular components known to be from a blood relative, recipients who have undergone marrow or peripheral blood progenitor cell transplantation, and recipients of cellular components whose donor is selected for HLA compatibility. Side Effects and Hazards Irradiation induces erythrocyte membrane damage. Irradiated red cells have been shown to have higher supernatant potassium levels than nonirradiated red cells. Removal of residual supernatant plasma before transfusion may reduce the risks associated with elevated plasma potassium. The expiration date of irradiated red cells is changed to 28 days after irradiation if remaining shelf life exceeds 28 days. There are no known adverse effects following irradiation of platelets; the expiration date is unchanged. Washing Description Washed components are typically prepared using 0.9% Sodium Chloride, Injection (USP) with or without small amounts of dextrose. Washing removes unwanted plasma proteins, including antibodies and glycerol from previously frozen units. There will also be some loss of red cells and platelets, as well as a loss of platelet function through platelet activation. The shelf life of washed components is no more than 24 hours at 1 to 6 C or 4 hours at 20 to 24 C. Washing is not a substitute for leukocyte reduction. Indications Washing of blood components is indicated to remove unwanted plasma when it contains constituents that predispose patients to significant transfusion reactions (eg, the removal of IgAcontaining plasma in providing transfusion support for an IgA-deficient recipient or in rare recipients experiencing anaphylactoid reactions to plasma components). For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 118 of 290 26 Specific Washed Components WASHED RED BLOOD CELLS (RED BLOOD CELLS WASHED) WASHED APHERESIS RED BLOOD CELLS (RED BLOOD CELLS PHERESIS WASHED) WASHED PLATELETS (PLATELETS WASHED) WASHED APHERESIS PLATELETS (PLATELETS PHERESIS WASHED) Volume Reduction Description Volume reduction is a special manipulation of cellular blood products using centrifugation. The process involves the aseptic removal of a portion of the supernatant, containing plasma and storage medium. Volume reduction removes excess plasma, thereby reducing unwanted plasma proteins, including antibodies. It is more commonly used in pediatric and in-utero transfusions. There will be some loss of platelet function through platelet activation as a result of volume reduction. The shelf life of volume-reduced components is no more than 24 hours at 1 to 6 C or 4 hours at 20 to 24 C. Indications Reducing the plasma volume of cellular components is indicated in cases where the volume status of a patient is being aggressively managed, such as in infants with compromised cardiac function. Volume reduction may be used to reduce exposure to plasma proteins or additives (such as mannitol), to achieve a specific component concentration, or to reduce exposure to antibodies targeting known recipient antigens (especially in an Apheresis Platelet unit containing ABO-incompatible plasma collected from a mother for the treatment of neonatal alloimmune thrombocytopenia). Contraindications Volume reduction is not a substitute for washing or for dosing with small aliquots. Volume reduction of platelets may result in adverse consequences associated with overtransfusion of platelets. Specific Volume-Reduced Components RED BLOOD CELLS VOLUME REDUCED (VOLUME REDUCED RED BLOOD CELLS) APHERESIS RED BLOOD CELLS VOLUME REDUCED (VOLUME REDUCED RED BLOOD CELLS PHERESIS) PLATELETS VOLUME REDUCED (VOLUME REDUCED PLATELETS) APHERESIS PLATELETS VOLUME REDUCED (VOLUME REDUCED PLATELETS PHERESIS) References General American Society of Anesthesiologists Task Force on Perioperative Blood Transfusion and Adjuvant Therapies. Practice guidelines for perioperative blood transfusion and adjuvant therapies: An updated report. Anesthesiology 2006;105:198-208. Desmet L, Lacroix J. Transfusion in pediatrics. Crit Care Clin 2004;20:299-311. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 119 of 290 27 Expert Working Group. Guidelines for red blood cell and plasma transfusion for adults and children. CMAJ 1997;156(11 Suppl):S1-S24. Gibson BE, Todd A, Roberts I, et al for the British Commitee for Standards in Haematology Transfusion Task Force. Transfusion guidelines for neonates and older children. Br J Haematol 2004;124:433-53. Herman JH, Manno CS, eds. Pediatric transfusion therapy. Bethesda, MD: AABB Press, 2002. Kleinman S, Chan P, Robillard P. Risks associated with transfusion of cellular blood components in Canada. Transfus Med Rev 2003;17:120-62. McFarland JG. Perioperative blood transfusions. Chest 1999;115:113S-21S. Popovsky MA, ed. Transfusion reactions. 3rd ed. Bethesda, MD: AABB Press, 2007. Price TH, ed. Standards for blood banks and transfusion services. 26th ed. Bethesda, MD: AABB, 2009. Roback JD, Combs MR, Grossman BJ, Hillyer CD, eds. Technical manual. 16th ed. Bethesda, MD: AABB, 2008. Roseff SD, Luban NL, Manno CS. Guidelines for assessing appropriateness of pediatric transfusion. Transfusion 2002;42:1398-413. Sazama K, DeChristopher PJ, Dodd R, et al. Practice parameter for the recognition, management, and prevention of adverse consequences of blood transfusion. Arch Pathol Lab Med 2000;124:61-70. Infectious Complications Alter HJ, Stramer SL, Dodd RY. Emerging infectious diseases that threaten the blood supply. Semin Hematol 2007;44:32-41. Busch MP, Caglioti S, Robertson EF, et al. Screening the blood supply for West Nile virus RNA by nucleic amplification testing. N Engl J Med 2005;353:460-7. Centers for Disease Control. Fatal bacterial infections associated with platelet transfusions— United States, 2004. MMWR Morb Mortal Wkly Rep 2004;54:168-70. Dodd RY, Notari EP IV, Stramer SL. Current prevalence and incidence of infectious disease markers and estimated window-period risk in the American Red Cross blood donor population. Transfusion 2002;42:975-9. Dodd RY. Transmission of parasites and bacteria by blood components. Vox Sang 2000;78 (Suppl 2):239-42. Fang CT, Chambers LA, Kennedy J, et al. 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Proceedings of a consensus conference: Towards an understanding of TRALI. Transfus Med Rev 2005;19:2-31. Holness L, Knippen MA, Simmons L, Lachenbruch PA. Fatalities caused by TRALI. Transfus Med Rev 2004;18:184-9. Kleinman S, Caulfield T, Chan P, et al. Toward an understanding of transfusion-related acute lung injury: Statement of a consensus panel. Transfusion 2004;44:1774-89. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 121 of 290 29 Kopko PM, Marshall CS, MacKenzie MR, et al. Transfusion-related acute lung injury: Report of a clinical look-back investigation. JAMA 2002;287:1968-71. Rana R, Fernandez-Perez ER, Khan SA, et al. Transfusion-related acute lung injury and pulmonary edema in critically ill patients: A retrospective study. Transfusion 2006;46:1478-83. Sanchez R, Toy P. Transfusion-related acute lung injury: A pediatric perspective. Pediatr Blood Cancer 2005;45:248-55. Silliman C, Ambruso D, Boshkov L. 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Factors affecting post transfusion platelet increments, platelet refractoriness and platelet transfusion intervals in thrombocytopenic patients. Blood 2006;105:4106-14. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 122 of 290 30 Citrate Toxicity Dzik WH, Kirkley SA. Citrate toxicity during massive blood transfusion. Transfus Med Rev 1988;2:76-94. Anaphylaxis Koda Y, Watanabe Y, Soejima M, et al. Simple PCR detection of haptoglobin gene deletion in anhaptoglobinemic patients with antihaptoglobin antibody that causes anaphylactic transfusion reactions. Blood 2000;95:1138-43. Lilic D, Sewell WA. IgA deficiency: What we should—or should not—be doing. J Clin Pathol 2001;54:337-8. Sandler SG. How I manage patients suspected of having had an IgA anaphylactic transfusion reaction. Transfusion 2006;46:10-13. Sandler SG, Zantek ND. Review: IgA anaphylactic transfusion reactions. Part II. Clinical diagnosis and bedside management. Immunohematol 2004;20:234-8. Vassallo RR. Review: IgA anaphylactic transfusion reactions. Part I. Laboratory diagnosis, incidence, and supply of IgA-deficient products. Immunohematol 2004;20:226-33. Red Blood Cells American Society of Anesthesiologists Task Force on Perioperative Blood Transfusion and Adjuvant Therapies. Practice guidelines for perioperative blood transfusion and adjuvant therapies: An updated report. Anesthesiology 2006;105:198-208. Bell EF, Strauss RG, Widness JA, et al. Randomized trial of liberal versus restrictive guidelines for red blood cell transfusion in preterm infants. Pediatrics 2005;115:1685-91. Bratton SL, Annich GM. Packed red blood cell transfusions for critically ill pediatric patients: When and for what conditions? J Pediatr 2003;142:95-7. Gould S, Cimino MJ, Gerber DR. Packed red blood cell transfusion in the intensive care unit: Limitations and consequences. Am J Crit Care 2007;16:39-48. Hébert PC, Yetisir E, Martin C. 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[Available at http://www.nhlbi.nih.gov/health/prof/blood/sickle/sc_mngt.pdf.] For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 123 of 290 31 NHLBI Clinical Alert: Periodic transfusions lower stroke risk in children with sickle cell anemia. Bethesda, MD: National Institutes of Health, 1997. [Available at http://www.nlm.nih. gov/data bases/alerts/sickle97.html.] Poole J, Daniels G. Blood group antibodies and their significance in transfusion medicine. Transfus Med Rev 2007;21:58-71. Stainsby D, MacLennan S, Thomas D, et al for the Standards in Haematology Writing Group. Guidelines for the management of massive blood loss. Br J Haematol 2006;135:634-41. Weiskopf RB, Viele MK, Feiner J, et al. Human cardiovascular and metabolic response to acute, severe isovolemic anemia. JAMA 1998;279:217-21. Welch HG, Meehan KR, Goodnough LT. Prudent strategies for elective red blood cell transfusion. Ann Intern Med 1992;116:393-402. 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Paucity of studies to support that abnormal coagulation test results predict bleeding in the setting of invasive procedures: An evidence-based review. Transfusion 2005; 45:1413-25. Spence RK. Clinical use of plasma and plasma fractions. Best Pract Res Clin Haematol 2006; 19:83-96. Stanworth SJ, Brunskill SJ, Hyde CJ, et al. Appraisal of the evidence for the clinical use of FFP and plasma fractions. Best Pract Res Clin Haematol 2006;19:67-82. Stanworth SJ, Brunskill SJ, Hyde CJ, et al. Is fresh frozen plasma clinically effective? A systematic review of randomized controlled trials. Br J Haematol 2004;126:139-52. Triulzi DJ. The art of plasma transfusion therapy. Transfusion 2006;46:1268-70. Vamvakas EC, Pineda AA. Meta-analysis of clinical studies of the efficacy of granulocyte transfusions in the treatment of bacterial sepsis. J Clin Apher 1996;11:1-9. Yazer MH, Cortese-Hassett A, Triulzi D. Coagulation factor levels in plasma frozen within 24 hours of phlebotomy over 5 days of storage at 1 to 60 C. Transfusion 2008;48:2525-30. Platelets Blanchette VS, Kuhne T, Hume H, Hellman J. Platelet transfusion therapy in newborn infants. Transfus Med Rev 1995;9:215-30. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 125 of 290 33 Blumberg N, Heal JM, Rowe JM. A randomized trial of washed red blood cell and platelet transfusions in adult leukemia. BMC Blood Disord 2004;4:6. Brecher M. The platelet prophylactic trigger: When expectations meet reality. Transfusion 2007;47:188-91. British Committee for Standards in Haematology, Blood Transfusion Task Force. Guidelines for the use of platelet transfusions. Br J Haematol 2003;122:10-23. George JN, Woolf SH, Raskob GE, et al. Idiopathic thrombocytopenic purpura: A practice guideline developed by explicit methods for the American Society of Hematology. Blood 1996;88:3-40. Heal JM, Blumberg N. Optimizing platelet transfusion therapy. Blood Rev 2004;31:1-14. Lind SE. Review: The bleeding time does not predict surgical bleeding. Blood 1991;77:2547-52. Pineda AA, Zylstra VW, Clare DE, et al. Viability and functional integrity of washed platelets. Transfusion 1989;29:254-7. Reed RL, Ciavarella D, Heimbach DM, et al. Prophylactic platelet administration during massive transfusion: A prospective, randomized, double blind clinical study. Ann Surg 1986;203:40-8. Schiffer CA, Anderson KC, Bennett CL. Platelet transfusion for patients with cancer: Clinical practice guidelines of the American Society of Clinical Oncology. J Clin Oncol 2001;l:1519-38. Schoenfeld H, Spies C, Jakob C. Volume-reduced platelet concentrates. Curr Hematol Rep 2006;5:82-8. Schoenfeld H, Muhm M, Doepfmer U, et al. The functional integrity of platelets in volumereduced platelet concentrates. Anesth Analg 2005;100:78-81. Slichter SJ. Relationship between platelet count and bleeding risk in thrombocytopenic patients. Transfus Med Rev 2004;18:153-67. Webert KE, Cook RJ, Sigouin CS, et al. The risk of bleeding in thrombocytopenic patients with acute myeloid leukemia. Hematology 2006;91:1530-7. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 126 of 290 34 Table 4. Summary Chart of Blood Components Action/Recipient Benefit Not Indicated for Special Precautions Hazards* Rate of Infusion Category Major Indications Red Blood Cells; Red Blood Cells, Low Volume; Apheresis Red Blood Cells Symptomatic anemia. Increases oxygencarrying capacity. Pharmacologically treatable anemia. Coagulation deficiency. Volume expansion. Must be ABO compatible. Infectious diseases. Hemolytic, septic/toxic, allergic, febrile reactions. TACO. TRALI. TA-GVHD. As fast as patient can tolerate but less than 4 hours. Deglycerolized Red Blood Cells See Red Blood Cells. IgA deficiency with anaphylactoid reaction. See Red Blood Cells. Deglycerolization removes plasma proteins. See Red Blood Cells. See Red Blood Cells. See Red Blood Cells. Hemolysis due to incomplete deglycerolization can occur. See Red Blood Cells. Risk of allergic and febrile reactions reduced. Red Blood Cells Leukocytes Reduced; Apheresis Red Blood Cells Leukocytes Reduced See Red Blood Cells. Reduction of febrile reactions. See Red Blood Cells Reduction of leukocytes reduces risk of febrile reactions, HLA alloimmunization and CMV infection. See Red Blood Cells. Leukocyte reduction should not be used to prevent TA-GVHD. See Red Blood Cells. See Red Blood Cells. Hypotensive reaction may occur if bedside leukocyte reduction filter is used. See Red Blood Cells. Washed Red Blood Cells See Red Blood Cells. IgA deficiency with anaphylatoid reaction. Recurrent severe allergic reactions to unwashed red cell products. See Red Blood Cells. Washing reduces plasma proteins. Risk of allergic reactions may be reduced. See Red Blood Cells. See Red Blood Cells. See Red Blood Cells. See Red Blood Cells. (Continued) For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 127 of 290 35 Table 4. Summary Chart of Blood Components (Continued) Special Precautions Rate of Infusion Action/Recipient Benefit Not Indicated for Symptomatic anemia with large volume deficit. Increases oxygencarrying capacity. Increases blood volume. Condition responsive to specific component. Treatment of coagulopathy. Must be ABO identical. See Red Blood Cells. As fast as patient can tolerate but less than 4 hours. Fresh Frozen Plasma (FFP) Clinically significant plasma protein deficiencies when no specific coagulation factors are available. TTP. Source of plasma proteins, including all coagulation factors. Volume expansion. Coagulopathy that can be more effectively treated with specific therapy. Must be ABO compatible. Infectious diseases. Allergic reactions. TACO. TRALI. Less than 4 hours. Plasma Frozen Within 24 Hours After Phlebotomy (PF24) Clinically significant deficiency of stable coagulation factors. Source of nonlabile plasma proteins. Levels of Factor VIII are significantly reduced and levels of Factor V and other labile plasma proteins are variable compared with FFP. Volume expansion. Deficiencies of labile coagulation factors including Factors VIII and V. Must be ABO compatible. See FFP. Less than 4 hours. Plasma Cryoprecipitate Reduced TTP. Plasma protein replacement for plasma exchange in TTP. Deficient in fibrinogen, Factor VIII, vWF, and Factor XIII. Deficient in highmolecular-weight vWF multimers as compared to FFP. Volume expansion. Deficiency of coagulation factors known to be depleted in this product, fibrinogen, Factors VIII, vWF, and XIII. Must be ABO compatible. See FFP. Less than 4 hours. Category Major Indications Whole Blood Hazards* (Continued) For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 128 of 290 36 Table 4. Summary Chart of Blood Components (Continued) Action/Recipient Benefit Category Major Indications Thawed Plasma Ω Bleeding patients except consumptive coagulopathy. Source of plasma proteins. Not indicated as treatment for isolated coagulation factor deficiencies. Reversal of warfarin effect. Levels and activation state of coagulation proteins in thawed plasma are variable and change over time. Levels and activation state of coagulation proteins in thawed plasma are variable and change over time. Initial treatment of patients undergoing massive transfusion. Coagulation support for life-threatening trauma/ hemorrhages. Not indicated as treatment for isolated coagulation factor deficiencies. The profile of plasma proteins in Liquid Plasma is poorly characterized. Levels and activation state of coagulation proteins are dependent upon and change with time in contact with cells, as well as the conditions and duration of storage. The profile of plasma proteins in Liquid Plasma is poorly characterized. Levels and activation state of coagulation proteins are dependent upon and change with time in contact with cells, as well as the conditions and duration of storage. Liquid Plasma Not Indicated for Special Precautions Hazards* Rate of Infusion Must be ABO compatible. See FFP. Less than 4 hours. Must be ABO compatible. See FFP. Less than 4 hours. (Continued) For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 129 of 290 37 Table 4. Summary Chart of Blood Components (Continued) Hazards* Rate of Infusion Infectious diseases. Allergic reactions. Less than 4 hours. Should not use some filters (check manufacturer’s instructions). Infectious diseases. Septic/toxic, allergic, febrile reactions. TACO. TA-GVHD. TRALI. Less than 4 hours. See Platelets. See Platelets. See Platelets. See Platelets. See Platelets. Reduction of leukocytes reduces risk of febrile reactions, HLA alloimmunization, and CMV infection. See Platelets. Leukocyte reduction should not be used to prevent TA-GVHD. See Platelets. See Platelets. See Platelets. Provides granulocytes with or without platelets. Infection responsive to antibiotics, eventual marrow recovery not expected. Must be ABO compatible. Should not use some filters (check manufacturer’s instructions). Infectious diseases. Hemolytic, allergic, febrile reactions. TACO. TRALI. TA-GVHD. One unit over 2-4 hours. Closely observe for reactions. Action/Recipient Benefit Category Major Indications Cryoprecipitated AHF; Pooled Cryoprecipitated AHF Hypofibrinogenemia. Factor XIII deficiency. von Willebrand disease. Hemophilia A. Provides fibrinogen, vWF, Factor XIII, and Factor VIII. Deficiency of any plasma protein other than those enriched in Cryoprecipitated AHF. Platelets; Pooled Platelets Bleeding due to thrombocytopenia or platelet function abnormality. Prevention of bleeding from marrow hypoplasia. Improves hemostasis. Plasma coagulation deficits. Some conditions with rapid platelet destruction (eg, ITP, TTP) unless life-threatening hemorrhage. Apheresis Platelets See Platelets. See Platelets. May be HLA (or other antigen) selected. Platelets Leukocytes Reduced; Pooled Platelets Leukocytes Reduced; Apheresis Platelets Leukocytes Reduced See Platelets. Reduction of febrile reactions. Reduction of HLA alloimmunization. Apheresis Granulocytes Ω ; Apheresis Granulocytes/ Platelets Ω See Platelets. Neutropenia with infection, unresponsive to appropriate antibiotics. Not Indicated for Special Precautions (Continued) For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 130 of 290 38 Table 4. Summary Chart of Blood Components (Continued) Category Major Indications Action/Recipient Benefit Not Indicated for Special Precautions Hazards* Rate of Infusion See component. See component. See component. See component. Further Processing: Irradiated Components See component. Increased risk for TAGVHD (eg, congenital immunodeficiencies, HLA-matched platelets or transfusions from blood relatives). Donor lymphocytes are inactivated reducing risk of TA-GVHD. *For all cellular components there is a risk the recipient may become alloimmunized and experience rapid destruction of certain types of blood products. Red-cell-containing components and thawed plasma (thawed FFP, thawed PF24, or Thawed Plasma) should be stored at 1-6 C. Platelets, Granulocytes, and thawed Cryoprecipitate should be stored at 20-24 C. Disclaimer: Please check the corresponding section of the Circular for more detailed information. TACO = transfusion-associated circulatory overload; TRALI = transfusion-related acute lung injury; TA-GVHD = transfusion-associated graft-vs-host disease; CMV = cytomegalovirus; TTP = thrombotic thrombocytopenic purpura; AHF = antihemophilic factor; ITP = immune thrombocytopenic purpura; vWF = von Willebrand factor. For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 131 of 290 39 093011 August 2009* For printed copies, please order online at www.aabb.org > Marketplace or call 1.866.222.2498. Page 132 of 290 American Journal of Transplantation 2010; 10: 26–29 Wiley Periodicals Inc. Special Feature C 2009 The Author C 2009 The American Society of Journal compilation Transplantation and the American Society of Transplant Surgeons doi: 10.1111/j.1600-6143.2009.02927.x Calculated PRA (CPRA): The New Measure of Sensitization for Transplant Candidates J. M. Cecka UCLA Immunogenetics Center, Los Angeles, CA Corresponding author: J. Michael Cecka, [email protected] The ways we measure whether a patient is sensitized to HLA antigens and to what extent sensitization affects access to transplantation have changed remarkably during the past decade. What we mean by sensitized and broadly sensitized today is heavily dependent upon the sensitivity of the test that is used to measure antibodies. Because we provide additional allocation points for broadly sensitized patients in the United States kidney allocation system in an effort to compensate for their biological disadvantage, some consistency and accountability are required. The calculated panel-reactive antibody, which provides an estimate of the percentage of deceased organ donors that will be crossmatch incompatible for a candidate provides both consistency and accountability. Key words: Access to transplantation, anti-HLA antibodies, crossmatching, donor-specific antibodies, histocompatibility, PRA Received 21 August 2009, revised 24 September 2009 and accepted for publication 05 October 2009 Sensitization remains a formidable barrier to transplantation. Patients who have preformed antibodies against HLA antigens are at risk for hyperacute rejection, accelerated acute rejection, antibody-mediated rejection, delayed graft function and longer term complications when transplanted from a donor expressing the target HLA antigens. We avoid donor-specific antibodies by crossmatching all potential donors and recipients before transplantation, and as a result, sensitized transplant candidates have limited access to transplantation in proportion to how broadly their anti-HLA antibodies react with the potential donor population. In the case of renal transplant candidates, those who are broadly sensitized (80+% panelreactive antibody; PRA) received additional points in the UNOS allocation system to compensate for their biological disadvantage. This is a strategy that did not work very effectively because over time, the most broadly sen26 sitized patients with a combination of long accumulated waiting time and four additional sensitization points appeared in the same order at the top of the match run for each blood group compatible donor. Although preliminary crossmatches eliminated most of these patients from consideration, many laboratories used a more sensitive test for their final than their preliminary crossmatch and positive final crossmatches were common among the broadly sensitized patients. To facilitate timely placement of organs, a limited number of broadly sensitized patients would be crossmatched and those patients would be the most likely to be crossmatch incompatible. UNOS implemented a new strategy on October 1, 2009, using unacceptable HLA antigens and a calculated PRA (CPRA) to award sensitization points that fundamentally changes how sensitized renal candidates are ranked for kidney offers. PRA has been the measure of sensitization since the recognition that catastrophic hyperacute rejection was associated with anti-donor HLA antibodies in the mid1960s (1). This landmark paper by Patel and Terasaki also described a simple surrogate test that could identify sensitized patients and estimate their likelihood of finding a crossmatch-compatible donor using a panel of normal blood donors as representative of the potential local organ donor pool. PRA was simply the percentage of this pool of donors to which a patient had reactive antibodies. A patient with 80% PRA would be crossmatch incompatible with 80% of donors. The crossmatch tests used today often are more sensitive than those that were used in the past. Even more importantly, the technologies available for identifying and measuring anti-HLA antibodies have undergone remarkable changes in the past decade and particularly in the past 5 years since the introduction of solid-phase tests using single HLA antigens produced by recombinant DNA technologies. The diversity of HLA antibody tests being performed by HLA laboratories has increased as these newer, more sensitive and more precise technologies have become available. Lacking organized guidelines for laboratories to indicate which PRA should be reported, many labs and transplant centers chose the highest PRA value among their test platforms because broadly sensitized patients receive four extra points. With diverse test platforms and sensitivities now many fold higher than previous lymphocytotoxicity tests permitted (2), sensitization estimates can Page 133 of 290 Sensitized Patients, PRA and CPRA 40 9000 8000 30 Luminex Flow PRA 25 20 15 10 5 0 1994 CPRA (%) 80+ 7000 Registrations Percent 80+% PRA 35 1-20 5000 0 3000 2000 Transplanted 1000 *68% *50% 0 0 1999 2004 *90% 4000 Waiting Added 21-79 6000 2009 1-20 21-80 PRA for Allocation 80+ *concordance Year Figure 1: Escalating sensitization levels and correlation with more sensitive test platforms. The percentage of sensitized patients who had 80+% PRA added to the UNOS waitlist, remaining on the waitlist at the end of each year and transplanted each year increased because the introduction of microparticle solid-phase tests using purified or recombinant HLA antigens, most notably following the introduction of Luminex technology for HLA antibody identification in 2002 (based on OPTN waitlist data as of July 3, 2009 and OPTN recipient histocompatibility data as of July 3, 2009). vary widely depending upon the method used to identify antibodies. Figure 1 shows that levels of sensitization reported to UNOS have escalated during the past 15 years. The percentage of sensitized patients with 80+% PRA who were added to the UNOS waitlist each year, who were on the waitlist at the end of each year or who were transplanted each year all increased by about 10% during this period. There was a clear rise in the percentage of broadly sensitized waitlist candidates and transplant recipients beginning in 2002, the year when solid-phase antibody tests using purified HLA antigens on the luminex platform were introduced. Although some centers may have become more adroit at transplanting their broadly sensitized patients through desensitization or transplantation in the face of a positive crossmatch (3–5), it seems more likely that the 2002 introduction and widespread use of solid-phase tests was a contributing factor in escalating PRA levels. The UNOS Histocompatibility Committee crafted a proposal to bring some accountability to PRA reporting and, at the same time, to take advantage of the new and evolving technologies. The calculated CPRA is based upon unacceptable HLA antigens to which the patient has been sensitized and which, if present in a donor, would represent an unacceptable risk for the candidate or the transplant program. The CPRA is computed from HLA antigen frequencies among approximately 12,000 kidney donors in the United States between 2003 and 2005 and thus American Journal of Transplantation 2010; 10: 26–29 Figure 2: Correlation between PRA and CPRA. Among 19,046 active registrations on the UNOS Kidney waiting list with a CPRA value, this figure shows the distribution of CPRA values calculated within each PRA group. In the group with 1–20% PRA, 50% also had 1–20% CPRA. Concordance was 68% for the 21–79% group and 90% for the 80+% PRA group. In the lower PRA groups, CPRA tended to be higher, whereas some patients in the 80+% PRA group did not have sufficient unacceptable antigens reported to warrant this CPRA level. CPRA was rounded to zero when only unacceptable antigens with a frequency less that 1% were listed (based on OPTN data as of June 12, 2009 and reported to the UNOS Histocompatibility Committee at its July 15 meeting). represents the percentage of actual organ donors that express one or more of those unacceptable HLA antigens. What adds accountability is that entering an unacceptable antigen for a patient means that kidneys from donors expressing that antigen will not be offered for that patient. The higher the CPRA, the fewer offers would be received. The proposal was approved by the UNOS Board of Directors and the initial phase was implemented in December 2007. During the first phase, the CPRA value appeared on the UNET waitlist form together with the traditional peak and current PRA values determined by the laboratories. At least one unacceptable antigen had to be entered for a patient to receive PRA points based on the traditional PRA. In the second phase, which began on October 1, 2009, the CPRA replaced peak and current PRA and sensitization points are now awarded based upon the CPRA. The UNOS Histocompatibility Committee monitored the first phase of CPRA during the past year and noted rapid acceptance. By March 2009, only 13 of the 256 U.S. kidney transplant programs—most small—had not entered unacceptable antigens for any of their patients. Figure 2 shows a comparison between the PRA value programs had designated for use in allocation with the patient’s CPRA. Concordance was high, with 90% of active renal candidates with a PRA 80% or higher having a CPRA in the same range. At the time of the analysis, about 12% of candidates who would have received points for 80+% PRA would not have gotten any points based upon their CPRA. The actual 27 Page 134 of 290 Cecka number of patients at risk of losing sensitization points was presented during Fall 2009 at each of the UNOS Regional meetings (tailored for each Region) to increase awareness and to encourage communication between transplant programs and their laboratories on the assignment of unacceptable HLA antigens. It may be that these patients had an inflated PRA that could not be justified based on the frequencies of the antigens to which they were sensitized. On the other hand, nearly 20% of active candidates whose PRA was 21–79% would receive points based on their CPRA. In fact, concordance was generally lower among the lower PRA groups due to underestimation of these patients’ sensitization levels using traditional PRA. CPRA provides a more accurate estimate of sensitization because it includes both class I and class II HLA specificities in the calculation, a major departure from traditional PRA, where class I and class II specificities are measured separately. Even B-cell panels, which express both class I and class II antigens are generally constructed to cover the class II HLA antigens and are not representative of HLA distributions in the general population. The new accountability built into the CPRA calculation requires a change in how we regard sensitization. A high traditional PRA value meant a high probability of a positive crossmatch, but because CPRA is based on unacceptable antigens that will prevent offers from those donors to which the patient is most highly sensitized, an offer for a patient with a high CPRA value should mean a high probability of a negative crossmatch. Previously, the same highly sensitized patients would appear at the top of each match run for donors with their blood group, and OPOs and centers were reluctant to set up final crossmatches for more than a few highly sensitized patients for fear of not placing the kidneys. The order of sensitized patients on the match run now is dictated by the donor’s HLA type and different sensitized patients will be ranked first for different donors, increasing their chances for a transplant. Indeed, several programs have reported a higher rate of transplantation for sensitized patients using the ‘virtual’ preliminary crossmatch (6–8). OPOs and centers that avoid broadly sensitized patients should abandon the practice of limiting final crossmatches for sensitized patients. Defining unacceptable antigens was left to the transplant programs and their laboratories. Some programs may be more aggressive and willing to assume the risks associated with donor-specific HLA antibodies, while others may not have the experience or resources to provide the more intensive and aggressive treatments for these patients. Communication between histocompatibility laboratories and the transplant programs they serve is a critical element for the success of this new method for assessing sensitization levels. The lack of standards for identifying anti-HLA antibodies and defining unacceptable antigens initially raised some concerns. A meeting between Laboratory Directors and 28 Transplant Physicians was held in Chicago in March 2008 to identify the problems of using solid-phase testing and to develop some solutions. There was general agreement that laboratories were quite good at defining strong antibodies—evidence from proficiency testing revealed excellent concordance among laboratories in identifying specific antibodies, even in complex antisera, that were present in high quantities. There was less agreement among laboratories for weaker antibodies and a major issue was a lack of data on the clinical relevance of antibodies that could only be detected by the very sensitive solidphase tests. The participants identified several strategies to improve and monitor uniformity in solid-phase antibody testing that have been or are about to be implemented, including comparisons of raw test results as well as interpretations among several laboratories using the same test specimens and collection of raw data by providers of proficiency testing in which all accredited laboratories must participate. Many laboratories had already begun to correlate the solid-phase test results with their crossmatch results and were able to eliminate their preliminary crossmatch tests with a ‘virtual’ preliminary crossmatch based on antibody strength and specificity to define what was unacceptable. Since that meeting, a number of laboratories have reported more detailed strategies to define unacceptable antigens and to avoid predictably positive crossmatches (9–14). Weak anti-HLA antibodies appear to have little clinical importance (15–17). Some have suggested that it is important that laboratories use multiple tests on different platforms when initially assigning unacceptable antigens to reduce the potential pitfalls of anomalous results from a single test (10,14). The solid phase tests have very fine sensitivity and not every antibody that can be detected is important. Although listing every HLA antigen to which a patient has detectable antibody as unacceptable will eliminate positive crossmatches, it may also eliminate all potential donor offers. The best strategy may be to begin predicting very strong positive crossmatches and tighten the thresholds to reduce the incidence of unacceptable crossmatches. There are some remaining problems with predicting crossmatches based upon antibody strength and specificities. We do not know whether multiple weak antibodies may have additive or synergystic effects on crossmatches or transplants. The single HLA antigen solid-phase tests also allow for detection of antibodies that react with antigens that are not always typed in deceased donors. Antibodies to the HLA-Cw, the DQ alpha chain and DP antigens may prevent accurate crossmatch prediction (18) for some patients. Extensive data on the role of these antibody specificities in transplantation are not available yet, but the antibodies may cause positive crossmatches when the target antigen is present in the donor (19,20). These antigens do not contribute to the CPRA calculation at present, because too few donors had been typed for these antigens to estimate their frequencies. The C-locus antigens are being revisited in the current update of frequency tables, but American Journal of Transplantation 2010; 10: 26–29 Page 135 of 290 Sensitized Patients, PRA and CPRA donors typed for DQ alpha chains and DP antigens are still extremely rare. Allele-specific antibodies are sometimes detected in the single antigen tests, which may cause problems because donor HLA alleles are rarely typed and because when an antibody detected against an allele of the patient’s own HLA antigen is detected, it cannot be listed as unacceptable. Despite these limitations, laboratories can accurately predict many incompatible crossmatches, streamlining allocation and providing more options for broadly sensitized patients. Like PRA, CPRA is a tool for characterizing and monitoring sensitization. Unlike PRA, the CPRA provides a meaningful estimate of transplantability for most patients, because it is calculated from unacceptable HLA antigens that will preclude offers from predictably crossmatch incompatible donors. The change to CPRA represents a paradigm shift in many ways. Although the concepts of unacceptable antigens and virtual crossmatches have been with us for many years, their widespread use and formal incorporation into the system for kidney allocation in the United States is unprecedented. As our ability to predict crossmatches and compatibility of donors for sensitized patients improves, it should be possible to encourage wider geographical sharing of deceased donor kidneys for this disadvantaged group beyond the current practice of sharing zero-HLA mismatched kidneys for sensitized patients. Accurate crossmatch prediction is a critical aspect of paired living-donor kidney exchanges as these increasingly involve patients and donors at different transplant centers. Finally, although the current focus is on their role in renal transplant allocation, unacceptable antigens and CPRA are also important tools for many thoracic programs that have begun using virtual crossmatches for distant donors to broaden the opportunities for their sensitized patients. Acknowledgments Dr. Cecka is currently Chair of the UNOS Histocompatibility Committee. The data analyses presented in this article were supported in part by Health Resources and Services Administration contract 234-2005-370011C. The content is the responsibility of the author alone and does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government. I thank Ann Harper and Anna Kucheryavaya for their excellent contributions of OPTN/UNOS data and analyses performed for the Histocompatibility Committee. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. References 20. 1. Patel R, Terasaki PI. Significance of the positive crossmatch test in kidney transplantation. N Engl J Med 1969; 280: 735–739. 2. Pei R, Lee JH, Chen T, Rojo S, Terasaki PI. Flow cytometric detec- American Journal of Transplantation 2010; 10: 26–29 tion of HLA antibodies using a spectrum of microbeads. Human Immunology 1999; 60: 1293–1302. Zachary AA, Montgomery RA, Ratner LE et al. Specific and durable elimination of antibody to donor HLA antigens in renal transplant patients. Transplantation 2003; 76: 1519–1525. Vo AA, Lukovsky M, Toyoda M et al. Rituximab and intravenous immune globulin for desensitization during renal transplantation. N Engl J Med 2008; 359: 242–251. Gloor J, Cosio F, Lager DJ, Stegall MD. The spectrum of antibodymediated renal allograft injury: Implications for treatment. Am J Transplant 2008; 8: 1367–1373. Bray RA, Nolen JD, Larsen C et al. Transplanting the highly sensitized patient: The Emory Algorithm. Am J Transplant 2006; 6: 2307–2315. Tambur AR, Leventhal J, Kaufman DB et al. Tailoring antibody testing and how to use it in the calculated panel reactive antibody era: The Northwestern University experience. Transplantation 2008; 86: 1052–1059. Bingaman AW, Murphey CL, Palma-Vargas J, Wright F. A virtual crossmatch protocol significantly increases access of highly sensitized patients to deceased donor kidney transplantation. Transplantation 2008; 86: 1864–1868. Vaidya S. Clinical importance of anti-human leukocyte antigenspecific antibody concentration in performing calculated panel reactive antibody and virtual crossmatches. Transplantation 2008; 85: 1046–1050. Zachary AA, Montgomery RA, Leffell MS. Defining unacceptable HLA antigens. Curr Opin Organ Transplant 2008; 13: 405–410. Nikaein A, Cherikh W, Nelson K et al. Organ procurement and transplantation network/united network for organsharing histocompatibility committee collaborative study to evaluate prediction of crossmatch results in highly sensitized patients. Transplantation 2009; 87: 557–562. Tambur AR, Ramon DS, Kaufman DB. Perception versus reality?: Virtual crossmatch—How to overcome some of the technical and logistic limitations. Am J Transplant 2009; 9: 1886–1893. Reinsmoen NL, Lai CH, Vo A et al. Acceptable donor-specific antibody levels allowing for successful deceased and living donor kidney transplantation after desensitization therapy. Transplantation 2008; 86: 820–825. Zachary AA, Sholander JT, Houp JA, Leffell MS. Using real data for a virtual crossmatch. Human Immunol 2009; 70: 574–579. Phelan D, Mohanakumar T, Ramachandran S, Jendrisak MD. Living donor renal transplantation in the presence of donor-specific human leukocyte antigen antibody detected by solid-phase assay. Human Immunol 2009; 70: 584–588. Aubert V, Venetz JP, Pantaleo G, Pascual M. Low levels of human leukocyte antigen donor-specific antibodies detected by solid phase assay before transplantation are frequently clinically irrelevant. Human Immunol 2009; 70: 580–583. Ho EK, Vasilescu ER, Colovai AI et al. Sensitivity, specificity and clinical relevance of different cross-matching assays in deceaseddonor renal transplantation. Transplant Immunol 2008; 20: 61–67. Tait BD, Hudson F, Cantwell L et al. Luminex technology for HLA antibody detection in solid organ transplantation (Review). Nephrology 2009; 14: 247–254. Vaidya S, Hilson B, Sheldon S, Cano P, Fernandez-Vina M. DPreactive antibody in a zero mismatch renal transplant pair. Hum Immunol 2007; 68: 947–949. Goral S, Prak EL, Kearns J, Bloom RD et al. Preformed donordirected anti-HLA-DP antibodies may be an impediment to successful kidney transplantation. Nephrol Dial Transplant 2008; 23: 390–392. 29 Page 136 of 290 Hematol Oncol Clin N Am 21 (2007) 147–161 HEMATOLOGY/ONCOLOGY CLINICS OF NORTH AMERICA Transfusion Risks and Transfusion-related Pro-inflammatory Responses George John Despotis, MDa,b,*, Lini Zhang, MDa, Douglas M. Lublin, MD, PhDb a Department of Anesthesiology, Box 8054, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA b Department of Pathology and Immunology, Box 8118, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA A pproximately 14.2 million red cell units and 1.6 million platelet transfusions (>80% single donor apheresis platelet units and the rest pools of usually six random donor platelet units) are administered in the United States each year [1,2,3]. Transfusion-related adverse events can occur with 10% of transfusions, and serious adverse events have been estimated to less than 0.5% of transfusions. Early estimates indicated that transfusion-associated adverse events could lead to a short-term (ie, not including disease transmission-related deaths) mortality of 1 to 1.2 deaths per 100,000 patients, or approximately 35 transfusion-related deaths/year in the United States [1,2]. More recent estimates suggest transfusion-related deaths are under-reported, and that long-term or total (ie, including disease transmission-related deaths) mortality is probably closer to one death per every 37,000 platelet or 130,000 red cell units administered, or approximately 220 transfusion-related deaths per year in the United States [1]. Even these estimates, however, may be underestimating transfusion-related mortality. For example, there were only 21 transfusion-related acute lung injury (TRALI)-related fatalities reported in 2003 [4], while projections based on an incidence of 1:5,000 transfusions with a 6% mortality rate indicate that this syndrome can account for at least 300 deaths annually in the United States. With respect to the leading causes of death, reports to the Food and Drug Administration (FDA) from 2001 to 2003 indicated that TRALI (16% to 22%), ABO Blood Group hemolytic transfusion reactions (12% to 15%), and bacterial contamination of platelets (11% to 18%) accounted for 40% to 50% of all transfusion-related deaths [5]. *Corresponding author. Department of Pathology and Immunology, Box 8118, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110. E-mail address: [email protected] (G.J. Despotis). 0889-8588/07/$ – see front matter doi:10.1016/j.hoc.2006.11.002 ª 2007 Elsevier Inc. All rights reserved. hemonc.theclinics.com 148 Page 137 of 290 DESPOTIS, ZHANG, & LUBLIN The composite risk of transmission of lipid-enveloped viruses such as HIV (1:1,400,000 to 2,400,000 U), human T-lymphotropic virus HTLV-I/II (1:250,000 to 2,000,000 U), hepatitis B (1:58,000 to 1: 149,000 U), hepatitis C (1:872,000 to 1,700,000 U) is estimated to be 1:83,000 U [2]. A substantial decline in the risk for transfusion-related viral transmission has occurred over the past 15 years related to implementation of donor screening and test strategies. This improvement came from immunoassays of increased sensitivity, and more recently from nucleic acid testing procedures that can detect viral RNA/DNA during the window period. Fifty percent of patients who acquire the hepatitis C virus (HCV) develop liver disease (although symptoms can be apparent within 2 weeks to 6 months, most patients are asymptomatic); 20% develop cirrhosis within 20 years, and 1% to 5% subsequently develop hepatocellular carcinoma. In contrast, transmission of hepatitis A or E, both enteric forms of hepatitis, is rare, and not associated with chronic infection. Other blood-borne, infectious diseases such as syphilis, Epstein-Barr virus, leishmaniasis, Lyme disease, brucellosis, B-19 parvovirus (increased prevalence in hemophiliacs), tick-borne encephalitis virus, Colorado tick fever virus, severe acute respiratory syndrome (SARS), West Nile virus, human herpes viruses, parasitic diseases (eg, malaria, babesiosis, toxoplasmosis, and Chagas’ disease), and variant Creutzfeldt–Jakob disease (vCJD) can be transmitted by means of transfusion, although many of these agents are rare in blood donors in the United States. Febrile, nonhemolytic transfusion reactions (NHTR) consisting of fever (>1 C) with a transfusion, occurs with 0.5% to 1.5% of red cell transfusions and can be related to one of several potential mechanisms. Preformed cytokines within the stored unit and host antibodies to donor (ie, graft) lymphocytes are generally self-limiting. The incidence of febrile NHTR may decrease by perhaps 50% with the use of prestorage leukoreduced blood components, and these reactions often can be prevented by pretreatment with acetaminophen. Although the estimated death rate related to HIV and hepatitis is declining, death related to transfusion caused by sepsis secondary to bacterial contamination of platelets is estimated to be at 20 deaths per million units of transfused platelets [2]. This is concerning, based on the substantially increased use of platelet transfusions in the United States to support cardiac surgery, oncology, and peripheral blood stem cell (PBSC) transplantation programs. The infusion of bacterially contaminated blood is an uncommon cause (0.0002% to 0.05%) of febrile transfusion reactions, occurring with 0.0001% to 0.002% of red blood cell (RBC) products stored at 4 C (the organism is often Yersinia enterocolitica) and at a much higher frequency with platelets stored at 20 C (ie, 0.05%) [1,2]. It, however, can lead to sepsis in 17% to 25% of patients transfused with contaminated blood, with an associated mortality rate of 26% [1]. Additionally, it accounts for at least 16% of transfusion-related fatalities previously reported to the FDA [6]. Bacterial growth more commonly occurs in components stored at room temperature (1:2,000 per apheresis platelet unit), especially if the storage interval is greater than 5 days, which has led to the current FDA limit for platelet out-date Page 138 of 290 TRANSFUSION-RELATED PRO-INFLAMMATORY RESPONSES 149 of 5 days. Very recently, the FDA licensed systems for storage of apheresis platelets for up to 7 days when bacterial cultures are performed on the product before release. Some form of bacterial quality control screening is performed for all platelet products, but it is not required that the method be as sensitive as culture systems. Transfusion of bacterially contaminated blood should be suspected when patients manifest one or more of the following symptoms or complications: high fever, chills, hemodynamic perturbations (eg, tachycardia, hypotension, shock), gastrointestinal (GI) symptoms (eg, emesis, diarrhea), hemoglobinuria, disseminated intravascular coagulation (DIC), or oliguria. Before transfusion, units should be examined for signs of bacterial contamination (eg, discoloration or dark color, bubbles). Transfusion-associated respiratory distress can be related to one of the following in order of decreasing frequency: fluid overload (transfusion-associated circulatory overload or TACO), allergic reactions, or TRALI. Although the exact incidence of circulatory overload related to transfusion is unknown (eg, 1 in every 200 to 10,000 U) [7], it is more likely in older patients with a history of congestive heart failure. Estimated prevalence rates of TRALI range from 1 in 432 U to 1 in 88,000 U of transfused platelets and 1 in 4,000 U to 1 in 557,000 U of red blood cells [8]. These ranges for transfusion associated circulatory overload (TACO) and TRALI reflect the clinical difficulty of diagnosis and the under-reporting of these transfusion reactions. TRALI can occur when anti-HLA (human leukocyte antigen) or anti-HNA (human neutrophil antigen) antibodies (more commonly observed in units from multiparous donors) and possibly neutrophil-activating lipid mediators within transfused units attack circulating and pulmonary leukocytes and stimulate complement activation and pulmonary injury [7]. This hypothesis, however, cannot explain all cases of TRALI, and a two-hit hypothesis was proposed previously [9]. The first event involves priming of neutrophils by some underlying condition (eg, trauma, infection, or surgery), which is followed by the infusion of substances by transfusion (eg, anti-HLA or anti-HNA antibodies, biologically active lipids). This leads to TRALI. This syndrome is characterized by acute (<6 hours after transfusion) onset of severe hypoxemia, bilateral noncardiogenic pulmonary edema, tachycardia/hypotension, and fever [10,11]. With ventilatory and hemodynamic supportive management, most patients recover within 48 to 96 hours. The prevalence of TRALI or development of acute respiratory compromise during or after transfusion has been advocated to be much more common in a recent Canadian consensus meeting [4]. In fact, with increased reporting to the FDA, the incidence of TRALI-related deaths (5% to 25% of patients who develop this syndrome) may be much higher than previously thought (as high as 18% of all deaths reported between 2001 and 2003), which places it close to the other leading causes of death (ie, acute hemolytic reactions, or bacterial contamination of platelets) [5,12,13]. Analysis of recent publications indicates that this syndrome is under-reported, because there were only 21 fatalities reported in 2003 [4], while low-end projections (ie, incidence of 1:5,000 transfusions with a 6% mortality rate) indicate that this syndrome can account for as many as 150 Page 139 of 290 DESPOTIS, ZHANG, & LUBLIN 300 deaths annually in the United States. In addition, if TRALI is not diagnosed correctly, treatment of these patients with therapy designed to manage cardiogenic pulmonary edema (ie, diuretic administration) can lead to adverse outcomes [10]. The pathophysiology of TRALI is still being elucidated, and it is uncertain whether the mechanisms will expand beyond anti-HLA and antiHNA antibodies and lipid mediators [14]. The understanding of the exact role of transfusion in the development of acute lung injury in susceptible patients with endothelial dysfunction (eg, trauma, cardiac surgery, sepsis) who also develop other end-organ dysfunction as part of multiorgan system failure is evolving. Hemolytic transfusion reactions can be immediate and life-threatening or delayed with minimal resulting clinical consequences (eg, serologic conversion). Current estimates indicate that the wrong unit of blood is administered 1 in every 14,000 U, of which transfusion of 1:33,000 U involves ABO incompatibility [2,15,16]. Catastrophic, acute hemolytic transfusion reactions (HTRs) are rare (ie, 1 in every 33,000 U to 1 in every 500,000 to 1,500,000 U). They can be fatal in 2% to 6% [1,2,6,15] of cases, however, and they account for at least (ie, these events are probably under-reported) 16 deaths every year (ie, 1:800,000 U transfused) in the United States [2,6]. Based on transfusion of 14.2 million units of red cells annually in the United States, there are approximately 1,000 nonfatal and 20 to 60 fatal mis-identification errors each year. This is in contrast to the 131 deaths (or 37% of the total deaths) related to ABO-incompatible transfusion reported between 1976 and 1985 [6,15]. Data from the United Kingdom for serious hazards of transfusion (SHOT) between 1996 and 2003 revealed that there were 2087 errors (1:11,000 transfusions), of which 24% resulted in major morbidity or death [15,16]. This report also revealed that in 50% of these events there were multiple errors in the process, that 70% of the errors occurred in clinical areas, and that the most frequent error (27% in 2003) involved a failure to link the unit to the patient at the bedside [16]. Catastrophic acute HTR initiates a sequence of responses, including complement and hemostatic system activation and neuroendocrine responses, which occur predominantly when host antibodies attach to red cell antigens on incompatible donor red cells. Generally, catastrophic acute HTR involves preformed IgM antibodies to ABO antigens, which lead to hemolysis by means of complement fixation and formation of immune complexes. As little as 10 to 15 mL of ABO-incompatible blood can initiate symptoms consistent with a severe, acute HTR such as: Fever in 48% (cytokine-related) Hypotension in 15% (secondary to bradykinin, mast cell histamine/serotonin and other vasoactive amines) Diffuse microvascular bleeding (secondary to hemostatic system activation or DIC) Complement-mediated acute intravascular hemolysis (eg, acute anemia, hemoglobinemia/hemoglobinuria in 87%) Page 140 of 290 TRANSFUSION-RELATED PRO-INFLAMMATORY RESPONSES 151 Acute renal insufficiency secondary to alpha-adrenergic vasoconstriction or deposition of antibody-coated stroma within the renal vasculature [17] The diagnosis can be confirmed with detection of free hemoglobin within the blood and urine in the setting of a positive direct antiglobulin test (DAT) with a mixed-field pattern on post-transfusion but not pretransfusion specimens. Additional tests that should be ordered include: Repeat ABO/Rhesus (Rh) testing of the unit Repeat cross-match and antibody detection on the patient’s pre- and postreaction samples and on blood from the unit Haptoglobin LDH Serial hemoglobin/hematocrit on patient specimens Examination of the blood remaining in the unit for hemolysis [18] Treatment is generally supportive and involves resuscitation to maintain organ perfusion using volume and vasopressor, which preferably do not vasoconstrict the renal bed (eg, low dose dopamine), maintenance of good renal urine output (>100 mL/h 24 hours) with intravenous crystalloids and diuretics, and on occasion transfusion support with hemostatic blood products in the setting of DIC and clinical bleeding. In contrast, most reactions to non-ABO antigens involve IgG-mediated extravascular clearance within the reticuloendothelial system (RES). They often are delayed (ie, 2 to 10 days), and they are not detected by pretransfusion testing, because they represent an anamnestic response. An exception to this pattern is Kidd antibodies, which are strong complement activators that can result in acute intravascular HTR. Finally, nonimmune HTR also can occur related to temperature (eg, overwarming with blood warmers, use of microwave ovens), use of hypotonic solutions for dilution of packed red blood cells (PRBCs), and mechanical issues during administration (ie, pressure infusion pumps, pressure cuffs, and small-bore needles). In addition, normal saline should be used to dilute the red cell units (calcium-containing solutions should be avoided), and units should be examined for large clots before transfusion. Because clerical or misidentification errors, which occur 1 in every 14,000 U, cause most immediate immune-mediated HTR [19], this potentially lethal complication can be prevented by diligent confirmation of patient and unit identification by individuals who initiate transfusion intraoperatively (ie, the anesthesiologist and circulating nurse). First, the blood bank confirms that the unit identification number and the ABO/Rh type on the unit of blood match the label attached to the unit. Most importantly, two clinical transfusionists must confirm that three pieces of patient identification (eg, patient name, hospital identification number, birth date, or social security number) on the hospital identification band or surrogate (eg, patient name plate imprint on the anesthesia record) needs to match the respective parameters on the unit of blood. To obtain a thorough understanding of hemolytic reactions, red cell antigen systems and serologic diagnostic tests are reviewed. Red cell antigen systems 152 Page 141 of 290 DESPOTIS, ZHANG, & LUBLIN include the ABO and related carbohydrate antigens (ie, H, P, I, and Lewis blood groups), the 48 Rh system antigens (including RhD) and over 200 other non-ABO/Rh antigens. The ABO carbohydrate and Rh polypeptide molecules reside on the surface of red blood cells with a US population frequency distribution (O: 44%, A: 43%, B: 9%, AB: 4%; RhDþ: 84%). ABO molecules express specific antigenic activity after individual sugar moieties are added to short sugar chains (ie, oligosaccharides) by several genetically determined glycosyltransferase enzymes. The ABO antigens are linked to cells (ie, red cells and other cells) by means of their association with membrane-bound proteins (ie, glycoproteins) or ceramide residues (ie, glycosphingolipids). Antibodies to the A and B antigens generally are thought to form as a result of exposure to other sources of antigen (ie, on bacteria) after the first few months of life. Blood group A and B individuals produce predominantly IgM antibodies (ie, anti-B and anti-A, respectively), whereas blood group O individuals produce both anti-B and anti-A IgG/IgM antibodies. Antibodies to Lewis and P1 antigens are generally clinically insignificant. Although there are 49 identified Rh antigens, the five principal antigens, D, C, E, c and e, and corresponding antibodies account for more than 99% of clinical issues involving the Rh system. The Rh system antigens are nonglycosylated, fatty-acylated polypeptides that traverse the red cell membrane 12 times. Although individuals who lack the D antigen do not form antibodies without blood exposure, the D antigen is highly immunogenic, and 80% of individuals who lack the D antigen will form anti-D once exposed through transfusion, or, at a lower frequency of approximately 15% through pregnancy. Over 200 other non-ABO/Rh, glycoprotein antigens can be identified on red cells, and some of these antigens also are expressed on other cells and body fluids. These non-ABO/Rh antigens frequently are subdivided into common (ie, MNS, Kell, Duffy, and Kidd systems) and uncommon antigen systems (eg, Lutheran, Diego, Yt, Xg, and Scianna). Antibodies to most of the common antigens can cause both clinically significant immediate and delayed HTR, but do not usually result in catastrophic, complement-mediated hemolysis, although this can occur with Kidd, Duffy, and S antibodies. Severe delayed HTRs are particularly common with anti-Kidd antibodies. Another important factor is the relative immunogenicity (ie, antibody formation), which can vary substantially between non-ABO antigens (eg, anti-D in 80%, anti-K in 10%, and anti-Fya in 1% of exposures). Several blood bank procedures (type, screen, and cross-match) are employed routinely to ensure transfusion of compatible blood. Patient ABO type is determined using direct agglutination of red cells and involves use of forward (ie, using the patient’s red cells with anti-A and anti-B reagents) and reverse (using the patient’s sera with reagent A1 and B cells) typing. Only forward typing is accurate in newborns or infants younger than 4 to 6 months based on transfer of maternal IgG molecules and lack of anti-A or anti-B production before 4 to 6 months of age. An antibody screen (ie, indirect antiglobulin or Coombs test) determines whether unexpected antibodies against common non-ABO red cell Page 142 of 290 TRANSFUSION-RELATED PRO-INFLAMMATORY RESPONSES 153 antigens are present, These antibodies are found in 0.2% to 0.6% of the general population [20], 1% to 2% of hospitalized patients, or in 8.3% of surgical patients. The antibody screen is performed using reagent red cells (ie, two or three screening cells) and a cross-linking antibody (rabbit/mouse antihuman globulin or Coombs reagent) that enhances the IgG-mediated agglutination of red cells. Sera is tested routinely only for antibodies to the common antigens, because the uncommon non-ABO antigens infrequently (ie, <0.01%) result in cross-match incompatibility of ABO compatible units. In the setting of a negative result on the antibody screen, the final cross-match can be done by a Coombs test, an immediate spin cross-match, or an electronic cross-match. The latter two procedures simply confirm the ABO compatibility of the donor unit and require less time. An elective procedure for which a type and screen or cross-matched blood has been requested should never commence until the antibody screen has been determined to be negative, or in the setting of a positive antibody screen, with antibodies and cross-matched compatible blood identified. Because availability of blood for same-day and urgent surgery is of critical importance, understanding a generally applicable timetable is important [20]. O negative (in some settings O positive for males) RBCs are generally immediately (<5 minutes) available, whereas type-specific RBCs are available within 15 minutes after receipt of the patient specimen. Cross-matched RBCs are generally available within 45 to 60 minutes by means of a type and cross-match (T&C) procedure using an immediate spin cross-match, which can be done if no antibodies are detected during the antibody screen. With a positive antibody screen, additional time (1 to several hours or even days) may be required to determine the antibodies and identify and cross-match blood that is antigennegative. In the event that antibodies are detected from the screen, the probability of finding compatible units can be calculated from the frequency of antigens for those preformed antibodies (eg, an Aþ individual with anti-c, anti-Fya antibodies will be compatible with 0.18 0.34 ¼ 0.06 or 6 of 100 Aþ units in the blood bank). Accordingly, obtaining cross-match compatible blood is also difficult when a patient has antibodies to a very common antigen (eg, k, in which case only 1 in 500 units is compatible). Clinicians also may be faced with an inability to obtain cross-match compatible blood in patients who have a warm auto-antibody. In this setting, more extensive serologic analysis using absorption techniques is required to identify alloantibodies; alternatively, if the patient has not been transfused recently, the partial phenotype can be determined to provide antigen-negative red cells. Single-donor, apheresis platelets (which now constitute >80% of platelet transfusions) are generally available immediately, whereas pooled platelet concentrates may take 10 to 15 minutes to process. The time required to obtain plasma or cryoprecipitate varies from 5 minutes to 30 minutes and is dependent on whether an inventory of thawed plasma units is maintained and the availability of a rapid thawing system. Mild urticarial symptoms (eg, rash, hives, or itching) occur with 1% of transfusions [21]. They are generally self-limiting and may improve with or be 154 Page 143 of 290 DESPOTIS, ZHANG, & LUBLIN prevented by antihistamine prophylaxis. More significant allergic transfusion reactions can occur with 0.1% to 0.3% units and are most likely related to reactions to other soluble transfusion constituents (eg, complement or other plasma proteins, drugs, or soluble allergens). Severe anaphylactic reactions, which occur infrequently (ie, 0.005% to 0.0007%), may be accompanied by IgE-mediated symptoms involving the respiratory (eg, dyspnea, bronchospasm), GI (eg, nausea, diarrhea, cramps) or circulatory (eg, arrhythmias, hypotension, or syncope) systems. IgA deficiency, which occurs in 1 of every 800 patients (only 30% of whom have preformed anti-IgA), is an uncommon cause of transfusion-associated anaphylaxis, and this diagnosis should be considered in any patient exhibiting anaphylaxis. Other potential causes of hemodynamic perturbations during or after a transfusion include: Citrate-related hypocalcemia (ie, with rapid infusion) Inadvertent intravenous air embolus (particularly with autologous blood recovery and reinfusion) Cytokine-mediated effects Bradykinin activation by leukoreduction filters, which may be aggravated by inadequate clearance in patients on angiotensin-converting enzyme inhibitors (80 reports to the FDA) Metabolic consequences of transfusion include coagulopathy, hypothermia (ie, with inadequate warming of refrigerated PRBC units) and hyperkalemia, because potassium concentration increases with the storage interval of PRBC units (eg, 42 mEq/L at 42 days of storage, or approximately 6 mEq total in a unit of PRBCs). In addition to development of alloantibodies to red cell antigens, several other immune-related phenomena can occur subsequent to transfusion. Antigens of the HLA system are determined by genes on the major histocompatibility complex on the short arm of chromosome 6. HLA gene products are cell– surface glycoproteins on all cells except mature red cells (class I comprised of HLA-A, B, or C antigens) or on B lymphocytes and cells of monocyte/macrophage lineage (class II comprised of HLA-DR, DQ, or DP gene cluster codes). Because they contribute to the recognition of self versus non-self, they are important with respect to rejection of transplanted tissue and long-term survival after solid organ and bone marrow transplantation. Alloimmunization to HLA antigens, which occurs commonly (ie, 20% to 70% of the time) in transfused and multiparous patients, can lead to immune-mediated platelet refractoriness (ie, insignificant or inadequate rise in platelet count not related to DIC, amphotericin, or splenomegaly), and febrile NHTR. Alloimmunization can be associated with development of autoantibodies, leading to autoimmune hemolytic anemia and development of post-transfusion purpura (ie, severe thrombocytopenia secondary to platelet-specific antibodies, usually anti-HPA-1a/PLA1 antibodies) 5 to 10 days after transfusion. Transfusion-associated immune system modulation has been shown to have beneficial effects, including improved renal allograft survival, reduced risk of recurrent spontaneous abortion, and Page 144 of 290 TRANSFUSION-RELATED PRO-INFLAMMATORY RESPONSES 155 reduced severity of autoimmune diseases such as rheumatoid arthritis. Proposed detrimental effects of transfusion-associated immune system modulation include increased cancer recurrence, perioperative infections, multiorgan system failure, and overall mortality, but these effects are controversial [22]. Transfusion, however, potentially can attenuate the immune response based on one of several potential mechanisms, including: a reduction in CD8 suppressor T cell function and number CD4 T helper cell number NK cell number and function Macrophage number and function, MLC response Response to mitogen, Cell-mediated cytotoxicity [23] Although several studies have demonstrated an independent effect (ie, using multivariate statistical models) of transfusion on increased perioperative infection ratesfour to five times) in numerous different surgical populations (ie, trauma [24–27], hip arthroplasty [25,28], spinal [29], colorectal [30–36] and cardiac [37–39]), the immune–modulatory effect of transfusion on the incidence of perioperative infection remains controversial. In addition, a recent meta-analysis involving review of 20 peer-reviewed articles and 13,152 patients revealed that transfusion was associated with perioperative infection (odds ratio of 3.45, range 1.43 to 15.15) [27]. Accordingly, four recent studies have demonstrated that administration of leukoreduced units may reduce perioperative infection in patients undergoing either colorectal [31] or GI, [40], or cardiac surgery [41,42], This has not been confirmed by other studies, however [43– 45]. Another recent retrospective analysis demonstrated a reduction in perioperative complications and mortality when leukoreduced units were used [44–46]. Rarely, transfusion-associated graft-versus-host disease, a syndrome manifested by several symptoms (ie, fever, dermatitis or erythroderma, hepatitis/enterocolitis, diarrhea, pancytopenia, or hypocellular bone marrow) may occur and be secondary to transfusion of cellular blood components that contain HLA-compatible T-lymphocytes, This occurs more frequently with transfusions from related individuals, and it can be prevented by standard irradiation of the blood product. Several recent studies have demonstrated that transfusion has an association with multiorgan system failure (MOSF) in the perioperative setting [47–49]. Although the exact mechanisms of the potential effect of transfusion on the incidence of this complication have not been elucidated, it is postulated that in patients who are at high risk (eg, trauma, long CPB intervals) for developing endothelial dysfunction, that either white cell lytic enzymes or other cellular debris injure an already dysfunctional endothelium. These studies also have demonstrated that there is an effect imposed by the age of the PRBC units and a load effect (ie, a direct relationship between the number of PRBCs units administered and MOSF rates). The prevalence of TRALI is expanding, in part 156 Page 145 of 290 DESPOTIS, ZHANG, & LUBLIN based on improved reporting and potential overlap between the diagnoses of TRALI versus MOSF in the high-risk patients. In addition, a recent study by van de Watering [41] demonstrated that mortality related to MOSF was reduced by 90% when patients undergoing cardiac surgery received leukoreduced PRBC units. Excessive bleeding requiring transfusion to correct anemia or hemostatic defects also may result in other complications such as stroke and may affect long-term mortality. In a large (n ¼ 16,000), recently published analysis [50], transfusion of more than 4 U of PRBC was the strongest (odds ratio ¼ 5) independent predictor with respect to perioperative stroke; it is not clear from this analysis whether transfusion support was a causative factor versus a predictor [50]. Another recent publication demonstrated a strong relationship between perioperative platelet transfusion and both stroke and death [51]. This was supported by another recent retrospective analysis that demonstrated that the death rate in a large series of patients undergoing cardiac surgery was much higher in patients who received platelets using multivariate statistical modeling [52]. Accordingly, a retrospective analysis demonstrated that long-term mortality may be doubled in patients who receive transfusion [53]. Because of their retrospective design, these studies cannot definitively link transfusion of either PRBC or platelet components with stroke or increased mortality, which may be reflecting colinearity or a statistical passenger effect with other comorbidities such as excessive bleeding. These studies, however, do help explain why agents such as aprotinin, which has been shown to reduce blood loss and transfusion by 50% to 90% and re-exploration rates by 70% in several large, randomized, placebo-controlled trials [54–57], also is associated with a 60% to 70% reduction in perioperative stroke [58] and reduced mortality [59]. Whether the beneficial effects of this agent are related to a reduction in the incidence of anemia and hypoperfusion related to bleeding in patients who also receive multicomponent transfusion or if they are the indirect effects of this agent on reducing transfusion in the bleeding patient with a concomitant reduction in transfusion-related sequelae remains unclear. Iron overload (ie, accumulation and deposition of iron within the vital organs) can occur in chronically transfused individuals such as patients with hemoglobinopathies and other susceptible patients. Emerging techniques to reduce disease transmission and hemolytic transfusion reactions are under active investigation and implementation. The introduction of nucleic acid technology (NAT) testing procedures can minimize blood-borne disease transmission by detecting viral RNA/DNA during the serologic window period. Inactivation of viral and bacterial RNA/DNA by photochemicals (eg, psoralen) with UVB irradiation is under investigation. Other techniques to reduce hemolytic transfusion reactions are under investigation such as conversion of A, B, or AB red cell units to O by means of enzymatic digestion of A and B antigens or generation of AB equivalent plasma by means of adsorption of anti-A and anti-B from plasma. In addition, new patient identification systems (eg, bar coding of identification bands and blood and the Bloodloc Safety System [Novatek Medical, Effingham, Illinois]) are being implemented to Page 146 of 290 TRANSFUSION-RELATED PRO-INFLAMMATORY RESPONSES 157 reduce transfusion of incompatible blood, in part based on a recent Joint Commission on Accreditation of Healthcare Organizations high-priority directive to enhance patient safety by means of improved patient identification. Although the on-going interface between transfusion medicine and perioperative services is an important topic, it is reviewed only briefly. The transfusion medicine service can provide assistance with respect to patients with unique clinical problems (eg, patients with cold agglutinin disease), use of specialized blood components, and implementation and monitoring of one of several nonpharmacologic blood conservation strategies such as preautologous donation [60,61], normovolemic hemodilution and cell salvage techniques [62], and other technical blood conservation methods [63]. Several pharmacologic agents (eg, tranexamic acid, epsilon amino caproic acid, or aprotinin) can be used to reduce bleeding and transfusion after cardiac, orthopedic, and liver transplantation procedures. Aprotinin, however, is the only agent that is FDA-approved for patients undergoing cardiac revascularization. This is also the only agent with established efficacy and safety based on multiple prospective, randomized (placebo-controlled) trials [54–57]. Other important interactions between transfusion medicine and perioperative services include establishment and monitoring of standardized transfusion protocols for red cells, hemostatic components, and emerging and off-label indications for factor concentrates (eg, factor VIIa) as important blood management strategies. Although several case reports have indicated that off-label use of activated factor VII can reverse life-threatening bleeding, cost and risk of thrombosis preclude routine use. Because any factor concentrate potentially can lead to life-threatening thrombotic complications in a subset of high-risk patients (ie, patients with congenital or acquired thrombotic disorders or systemic activation of the hemostatic system such as with DIC or after cardiac surgery), large clinical trials evaluating the efficacy and safety of rFVIIa are needed before any widespread use can be recommended [64]. Use of point-of-care or laboratory-based coagulation results when coupled to a standardized approach (ie, algorithm) for managing bleeding after cardiac surgery has been shown to result in a 50% reduction in total donor exposures in all but one [65] of eight published studies [66–72]. Other studies also have demonstrated that certain patient subgroups may benefit from off-label use of DDAVP with respect to reduced bleeding and transfusion such as patients who have: Type I von Willebrand’s disease Uremia-induced platelet dysfunction A platelet defect after cardiac surgery as identified using point-of-care platelet function tests [73,74] Use and monitoring of point-of-care diagnostics to guide transfusion and pharmacologic management of bleeding also can be enhanced by means of a collaborative approach with the transfusion medicine service with respect to implementation, quality control monitoring, and regulatory compliance (eg, Joint Commission or College of American Pathologists). Future availability of blood 158 Page 147 of 290 DESPOTIS, ZHANG, & LUBLIN substitutes may be critical in unique clinical situations such as in patients with multiple antibodies, with Jehovah’s Witness patients, and in trauma settings. These agents also may enhance blood conservation techniques or organ preservation because of their ability to enhance tissue oxygenation. Despite improvements in blood screening and administration techniques, serious adverse events related to transfusion continue to occur, albeit at a much lower incidence. In addition to the development and implementation of new screening and blood purification/modification techniques, the incidence and consequences of transfusion reactions can be reduced by a basic understanding of transfusionrelated complications. Although acute hemolytic transfusion reactions, transfusion-associated anaphylaxis, sepsis, and TRALI occur infrequently, diligence in administration of blood and monitoring for development of respective signs/symptoms can minimize the severity of these potentially life-threatening complications. In addition, emerging blood banking techniques such as psoralen-UV inactivation of pathogens and use of patient identification systems may attenuate the incidence of adverse events related to transfusion. With respect to optimizing blood management by means of pharmacologic and nonpharmacologic strategies, the ability to reduce use of blood products and to decrease operative time or re-exploration rates has important implications for not only disease prevention, but also for blood inventory and costs and overall health care costs. References [1] Goodnough LT, Brecher ME, Kanter MH, et al. Transfusion medicine: blood transfusion. N Engl J Med 1999;340:438–47. 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A multicenter, randomized, double-blind, placebo-controlled study. J Thorac Cardiovasc Surg 1994;107(2): 543–53. [55] Lemmer JH, Dilling EW, Morton JR, et al. Aprotinin for primary coronary artery bypass grafting: a multicenter trial of three dose regimens. Ann Thorac Surg 1996;62:1659–67. [56] Levy JH, Pifarre R, Schaff HV, et al. A multicenter, double-blind, placebo-controlled trial of aprotinin for reducing blood loss and the requirement for donor–blood transfusion in patients undergoing repeat coronary artery bypass grafting. Circulation 1995;92:2236–44. Page 150 of 290 TRANSFUSION-RELATED PRO-INFLAMMATORY RESPONSES 161 [57] Alderman EL, Levy JH, Rich JB, et al. Analyses of coronary graft patency after aprotinin use: results from the International Multicenter Aprotinin Graft Patency Experience (IMAGE) trial. J Thorac Cardiovasc Surg 1998;116(5):716–30. [58] Smith PK. Aprotinin: safe and effective only with the full-dose regimen. Ann Thorac Surg 1996;62:1575–7. 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[65] Capraro L, Kuitunen A, Salmenpera M, et al. On-site coagulation monitoring does not affect hemostatic outcome after cardiac surgery. Acta Anaesthesiol Scand 2001;45(2): 200–6. [66] Despotis GJ, Santoro SA, Spitznagel E, et al. Prospective evaluation and clinical utility of onsite monitoring of coagulation in patients undergoing cardiac operation. J Thorac Cardiovasc Surg 1994;107(1):271–9. [67] Spiess BD, Gillies BS, Chandler W, et al. Changes in transfusion therapy and re-exploration rate after institution of a blood management program in cardiac surgical patients. J Cardiothorac Vasc Anesth 1995;9:168–73. [68] Shore-Lesserson L, Manspeizer HE, DePerio M, et al. Thromboelastography-guided transfusion algorithm reduces transfusions in complex cardiac surgery. Anesth Analg 1999;88: 312–9. [69] Nuttall GA, Oliver WC, Santrach PJ, et al. Efficacy of a simple intraoperative transfusion algorithm for nonerythrocyte component utilization after cardiopulmonary bypass. 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A controlled clinical trial with thromboelastographic risk stratification. Anesthesiology 1992;77(1):38–46. Page 151 of 290 Recombinant Human Erythropoietin in Anemic Patients with End-Stage Renal Disease Results of a Phase I11 Multicenter Clinical Trial Joseph W. Eschbach, MD; Mohamed H. Abdulhadi, MD; Jeffrey K. Browne, PhD; Barbara G. Delano, MD; Michael R. Downing, PhD; Joan C . Egrie, PhD; Roger W. Evans, PhD; Eli A. Friedman, MD; Stanley E. Graber, MD; N. Rebecca Haley, MD; Stephen Korbet, MD; Sanford B. Krantz, MD; A. Peter Lundin, MD; Allen R. Nissenson, MD; David A. Ogden, MD; Emil P. Paganini, MD; Barbara Rader, MEd.; Edwin A. Rutsky, MD; John Stivelman, MD; William J. Stone, MD; Paul Teschan, MD; John C . Van Stone, MD; David B. Van Wyck, MD; Kenneth Zuckerman, MD; and John W. Adamson, M D Study Objective: To determine the effectiveness and safety of recombinant human erythropoietin (rHuEpo) . Patients: Hemodialysis patients (333) with uncomplicated anemia (hematocrit < 0.30). All received rHuEpo intravenously, three times per week a t 300 or 150 U / k g body weight, which was then reduced to 75 U/kg and adjusted to maintain the hematocrit a t 0.35 k 0.03 (SD). Results: The baseline hematocrit (0.223 k 0.002) increased to 0.35, more than 0.06 over baseline within 12 weeks in 97.470 of patients. Erythrocyte transfusions (1030 within the 6 months before rHuEpo therapy) were eliminated in all patients within 2 months of therapy. Sixty-eight patients with iron overload had a 39% reduction in serum ferritin levels after 6 months of therapy. The median maintenance dose of rHuEpo was 75 U/kg, three times per week (range, 12.5 to 525 U / k g ) . Nonresponders had complicating causes for anemia: myelofibrosis, osteitis fibrosa, osteomyelitis, and acute or chronic blood loss. Adverse effects included myalgias, 5%; iron deficiency, 43 %; increased blood pressure, 35%; and seizures, 5.4%. The creatinine, potassium, and phosphate levels increased slightly but significantly. The platelet count increased slightly but there was no increase in clotting of vascular accesses. Conclusions: The anemia of hernodialysis patients is corrected by rHuEpo resulting in the elimination of transfusions, reduction in iron overload, and improved quality of life. Iron stores and blood pressure must be monitored and treated to maintain the effectiveness of rHuEpo and to minimize the threat of hypertensive encephalopathy. Annals oflnternal Medicine. 1989;111:992- 1OOO. From the University of Alabama at Birmingham, Birmingham, Alabama; the University of Arizona, Tucson, Arizona; The Cleveland Clinic, Cleveland, Ohio: the Downstate Medical Center, New York, New York; the University of Missouri at Columbia, Columbia, Missouri; Rush-PresbyterianSt. Luke’s Medical Center, Chicago, Illinois; the University of California at Los Angeles, Los Angeles, California: Vanderbilt University and the Nashville Veterans Affairs Medical Center, Nashville, Tennessee; and the University of Washington/Northwest Kidney Center, Seattle, Washington. For current author addresses. see end of text. 992 0 1 9 8 9 American College of Physicians Severe anemia is one of the major limitations to rehabilitation in patients with end-stage renal disease. The anemia is primarily due to the inability of the diseased kidney to secrete adequate amounts of erythropoietin (1). In late 1986 and early 1987, the results of the initial phase 1-11 clinical trials with recombinant human erythropoietin (rHuEpo) in severely anemic patients on hemodialysis were reported, including 25 patients in the United States ( 2 ) and 10 in the United Kingdom ( 3 ) . All responded with an effective increase in erythropoiesis, cessation of transfusion requirements, normalization of hemoglobin and hematocrit, and improvement in general well-being. These studies showed the clinical benefits of treatment. In addition, five potential issues related to patient management were identified. First, approximately 25% of the patients developed an increase in blood pressure which required initiation or modification of antihypertensive therapy. Second, two seizures occurred in the first 35 patients treated with rHuEpo (2, 3 ) . Third, functional or absolute iron deficiency appeared to limit the effectiveness of the drug. In two-thirds of the patients, supplemental iron was required to restore or maintain a full erythropoietic response to rHuEpo ( 2 ) . Fourth, there were concerns that dialysis would become less efficient in patients with higher hematocrits and lead to fatal complications such as hyperkalemia ( 2 ) . Finally, there was the possibility that vascular thromboses in general, and access thrombosis in particular, might increase when the hematocrit increased. Increased heparin doses during dialysis were required in some patients. After the initial studies, a phase I11 multicenter clinical trial of rHuEpo in patients on hemodialysis was initiated in the United States in the autumn of 1986. The trial was designed to determine the overall effectiveness of rHuEpo and its effect on patient quality of life, evaluate the safety of the drug, and determine what medical consequences, if any, might result from near-normalization of the hematocrit in a larger population of patients with end-stage renal disease. As reported in the earlier studies, rHuEpo was found to be effective in virtually all anemic patients on hemodialysis and, although the management of blood pres- Page 152 of 290 sure and iron status in these patients will require close attention by physicians, the drug is well tolerated and has proved to be safe. Patients and Methods Patients The study was approved by the Human Subjects Review Committees of the nine participating centers and all patients gave informed consent. The centers participating in the phase 111clinical trial included the University of Alabama at Birmingham, the University of Arizona, the Cleveland Clinic, Downstate Medical Center in New York, the University of Missouri at Columbia, Rush-Presbyterian-St. Luke’s Medical Center in Chicago, the University of California at Los Angeles, Vanderbilt University and the Nashville VA Medical Center, and the University of Washington/Northwest Kidney Center. To be included in the study, patients met the following criteria: They had a hematocrit of 0.30 or less; were medically stable on hemodialysis and known to the participating dialysis center for a minimum of 3 months; had a life expectancy estimated to be at least 6 months; had no hemolysis or blood loss; had a serum ferritin level greater than 100 pg/L with a percent-transferrin saturation of 20 or more; were 18 years or older; and had stable liver enzyme tests including alanine aminotransferase no greater than twice the upper limit of normal for the reporting center’s laboratory. Exclusion criteria included poorly controlled hypertension with diastolic blood pressures persistently greater than 100 mrn Hg, history of a seizure disorder, systemic hematologic disease or unexplained acquired microcytosis, active inflarnmatory disease, therapy with immunosuppressive drugs, or concurrent diseases that might impair the response to rHuEpo. A total of 333 patients were entered into the study: 159 men and 174 women, with a mean age of 5 1 years (range, 18 to 8 1) . The renal diseases included chronic glomerulonephritis, 23%; hypertension, 23%; diabetes mellitus, 18%; obstructive uropathy, 5 % ; polycystic kidney disease, 4%; interstitial nephritis, 2%; pyelonephritis, 2%; miscellaneous, 15%; and unknown, 8%. Recombinant Human Erythropoietin The rHuEpo was provided as Epogen by Amgen Inc., Thousand Oaks, California, and was purified from the growth medium of Chinese hamster ovary cells into which the human erythropoietin gene had been transfected and expressed (4, 5). The rHuEpo preparation was formulated in a sterile buffered saline solution containing 0.25 70human serum albumin. by a Coulter counter (Coulter Electronics, Inc., Miami, Florida); and by the decrease in erythrocyte transfusion requirements. The leukocyte count and differential, platelet count, serum iron, total iron binding capacity, and serum ferritin were also measured serially. In addition, a questionnaire designed to evaluate quality of life (6, 7 ) was completed by the patients before initiating rHuEpo therapy and approximately 6 and 10 months later. Potential adverse organ effects of rHuEpo and adequacy of dialysis were monitored by serial liver function tests, serum albumin, electrolyte, and mineral panel including sodium, potassium, chloride, CO2, blood urea nitrogen, creatinine, uric acid, calcium, and phosphorus and by blood coagulation tests. Laboratory values are expressed as mean k standard error. A physical examination, chest roentgenogram, and electrocardiogram were done on patients before initiation of therapy, after the target hematocrit was attained, and every 3 months thereafter. Blood was measured initially and then periodically to determine antibodies to rHuEpo using a radioimmunoprecipitation assay (2). Results Effectiveness of Recombinant Human Erythropoietin We evaluated the efficacy of rHuEpo by increases in hematocrit, decreases in transfusion requirements, and changes in patient quality of life. Treatment with rHuEpo caused dose-dependent increases in hematocrit (Figure 1). The 35 patients receiving 300 U/kg three times per week during the acute phase of study all responded, achieving the target hematocrit of 0.35, and a group average hematocrit increase of 0.13 above baseline within 6 to 8 weeks. The 201 patients who received an acute-phase dose of 150 U/kg had a hematocrit rate of rise that was approximately 55% that of the 300 U/kg group. By study week 10 their group average hematocrit was within the target range (0.32 to 0.38). The remaining 97 study patients initially received an acute-phase rHuEpo dose of 300 U/kg, which was subsequently reduced to 150 U/kg. Of the 309 patients who received treatment for at least 4 1 Study Design Recombinant human erythropoietin was administered as an intravenous bolus directly into the venous return line or into the arteriovenous access after the dialyzer was disconnected, three times a week. On the basis of results of the initial clinical study ( 2 ) , a starting dose of 300 U/kg body weight was chosen for the initial (acute) phase of the study. The initial dose was reduced to 150 U/kg several months after the beginning of the study, and those patients receiving 300 U/kg had their dose changed to 150 U/kg. When the hematocrit reached 0.35, patients entered the maintenance phase of the protocol, when the rHuEpo dose was reduced to 75 U/kg. A stable hematocrit of 0.32 to 0.38 (0.35 & 0.03) was maintained by adjusting the three times weekly dose as necessary in increments of 12.5 to 25 U/kg. If the hpmatocrit exceeded 0.40,rHuEpo was withheld until the hematocrit fell below 0.38. Responses to rHuEpo were monitored by serial measurements of the reticulocyte count (corrected for the hematocrit); hemoglobin and hematocrit, which were determined 15 December 1989 0.22 k B /I 2 4 6 I 8 I 1 10 12 Week on study 1 14 16 I 18 Figure 1. The mean hematocrit values a t biweekly intervals for 35 patients receiving 300 U r H u Ep o A g body weight (circles) or 201 patients receiving 150 U (dimonds) rHuEpoAg. The r H u E p was given intravenously three times per week. Annals oflnfernalMedicine Volume 11 1 Number 12 993 Page 153 of 290 Table 1. Effmtsof Recolnbinant Hvman Evthropoietin on Hematologic Values Variable Baseline Number of Patients (fSE) Hematocrit Hemoglobin, mmoUL WdL) Reticulocytes, corrected Mean cell volume, fz. Platelet count, x 1@/L Leukocyte count, X 1@/L Serum iron, pmoUL ( P d W Transferrin, pmol/L (FddL) Transfemn saturation, % 304 0.223 0.002 4.65 (7.5) 0.06 (0.1) 0.01 1 304 298 O.OOO4 90.7 1.3 224.0 4.6 6.5 0.1 17.7 (98.6) 0.8 (4.4) 43.3 (241.7) 0.7 (3.9) 41.1 303 303 304 285 286 286 1.5 Ferritin, p&L 962.2 89.4 280 Baseline (fSE) Maintenance Number of Patients 0.343 0.002 6.95 (1 1.2) 0.06 (0.1) 0.026 O.OOO9 90.6 0.5 252.9 5.6 6.6 0.1 15.3 (85.6) 1.9 (10.7) 43.2(241.2) 1.5 (8.5) 30.1 1.2 628.5 75.7 P Value. 304 < 0.0005 304 < 0.0005 298 < 0.0005 303 NS 303 < 0.0005 304 NS 285 NS 286 NS 286 < 0.0005 280 < 0.0005 Compared with baseline, using paired t-test. NS = not significant. weeks, the hematocrit of 295 patients increased to 0.35 or rose a minimum of 0.06 over baselinean effective response rate of 95.5%. Six more patients met these criteria by the end of 18 weeks of therapy, for a total response rate of 97.4%. Most patients achieved the target hematocrit range within the first 12 weeks of treatment. The 333 study patients required a total of 1030 erythrocyte transfusions during the 6 months before initiation of rHuEpo therapy (an average of 0.52 units per patient per month) in order to maintain a hematocrit at a level that permitted usual daily activities. After therapy, transfusion requirements decreased progressively (Figure 2) and after month 2 of treatment virtually all patients were transfusion-independent and have remained so to date. Occasional transfusions have been administered following blood losses due to surgery or dialysis, or when rHuEpo therapy was interrupted. In addition, iron overload, arbitrarily defined as a serum ferritin greater than lo00 ng/mL, and present in 68 patients at baseline, was reduced. In these patients, serum ferritin levels decreased a mean of 39% after 6 months of rHuEpo therapy (3179 f 258 pg/L compared with 1949 f 213 pg/ L). Of the eight evaluable patients who failed to achieve a hematocrit of 0.35, or 0.06 or more over baseline, one each had myelofibrosis, thalassemia minor, osteomyelitis, and both acute and chronic blood loss. The other four patients were treated with rHuEpo for less than the minimum 12-week evaluation period before withdrawing from the study. Figure 3 shows the distribution of doses required to maintain the hematocrit in the target range. The median dose was 75 U/kg but doses of as little as 12.5 U/ kg or as high as 525 U/kg were required for occasional patients. The distribution of maintenance doses is 994 15 December 1989 Annals oflntemaf Medicine skewed: 17% of the patients required more than 150 U/kg given intravenously three times weekly to maintain a stable hematocrit. Patient maintenance doses have remained relatively stable, and no patient has developed resistance to rHuEpo. In addition, no evidence of antibody formation to rHuEpo has been detected t o date. Table 1 summarizes the pertinent hematologic data observed at baseline, when patients began maintenance rHuEpo therapy, and after 6 and 10 months of maintenance rHuEpo therapy. Significant increases in hematocrit, hemoglobin, and corrected reticulocyte O-7 Weeks Figure 2. Transfusion requirements (mits/patient) per month for 6 months before initiation of rHuEpo therapy ( p ~and ) at Cweek intervals thereafter. At week 52, one patient autodonated three units in the previous month for elective hip surgery. Volume 1 1 1 Number 12 Page 154 of 290 Table 1. (Continued) 6 (* Months Number of Patients Maintenance P Value* (kSE) SE) 0.338 0.003 6.89( 11.1) 0.06 (0.1) 0.019 0.0007 89.6 0.6 241.0 5.4 6.7 0.2 11.6 (65.0) 0.6 (3.2) 39.8(222.4) 0.6 (3.5) 30.3 1.4 538.6 71.2 233 < 0.0005 233 < 0.0005 228 < 0.0005 232 10 Months 0.353 0.004 7.14(11.5) 0.06 (0.1) 0.02 1 0.0013 91.9 1.o 232.0 7.0 6.7 0.3 12.3 (68.4) 0.8 (4.6) 38.1(212.8) 0.8 (4.5) 33.6 2.4 796.7 145.7 NS 23 1 < O.oOO5 233 0.03 210 < 0.0005 21 1 < 0.0005 209 < 0.0005 204 < 0.0005 count occurred with rHuEpo therapy. There were no significant alterations in the mean erythrocyte volume, total leukocyte count, or serum transferrin level. The leukocyte differential remained normal except for an increase in the percent of monocytes (5.6 f0.2 at baseline to 6.7 f0.2 6 months after entry into the maintenance phase, P < 0.01). Most patients reported an increase in their quality of life as manifested by increased exercise tolerance and activity levels, higher energy levels, improved sleep-wake cycles, improved appetite, increased body warmth, and an enhanced perception of their health status. A quantitative assessment of the effect of nearcorrection of anemia with rHuEpo therapy on the quality of life is summarized in Table 2. Of 130 patients completing questionnaires at baseline and after approximately 6 and 10 months of rHuEpo therapy, there was almost a two-fold increase in the percentages of patients who had no complaints and were able to carry on normal activity (26%, 45%, and 44%, respectively, per Karnofsky scoring). Conversely, 46% of patients complained of low or no energy at baseline, whereas only 23% and 22% had these complaints during the immediate and later maintenance treatment phases, respectively. Of perhaps greater clinical significance are the reports of energy level as determined by the Nottingham Health Profile. A score of 100 on this profile indicates complete limitation; a score of 0 indicates the absence of limitations. Energy level improved from a baseline score of 47 to 32 after the hematocrit was acutely corrected and then to 28 at further follow-up. In response to objective quality-of-life questions, particularly those relating to energy and activity levels, the patients reported a statistically significant and sustained improvement between baseline and both follow-up time periods. 15 December 1989 Number of Patients P Value* 104 < 0.0005 104 < 0.0005 101 < 0.0005 104 0.006 104 NS 104 0.0 1 96 < 0.0005 97 < 0.0005 96 < 0.0005 94 < 0.0005 Patient Study Status Of the 333 patients beginning rHuEpo therapy, 266 were on therapy as of 30 November 1987, 13 months after the start of the trial. The reasons for patient withdrawal from the study included renal transplantation in 15 patients; death, 22 patients; possible toxicity, 9 patients; voluntary patient withdrawal, 13 patients; and other causes, 8 patients. Of the 7 who 60 50 - v) I- z W F 40- 8 B I"i 20 "'1 * 0 0 400 ,600 DOSE OF rHuEPO (U/kg) Figure 3. The distribution of maintenance doses of rHuEpo required to maintain the hematocrit between 0.32 and 0.38. The dose level refers to the upper value within each 25 U/kg dose range. The rHuEpo was given intravenously three times per week. Annals ofhternaf Medicine Volume 1 1 1 Number 12 995 Page 155 of 290 Table 2. Effect of Recombinant Human Erythropoietin on Patients’ Functional Impairment, Energy, and Activity Level (n = 130) Baseline 0.237 Hematocrit, mean Functional impairment Normal, no complaints; able to carry on normal activity (Karnofsky), % ofpatients 25.9 Activity level Very or mostly active, % of pa tients 19.8 Energy level Patient reporting very full of energy or fairly energetic most of the time, % 25.9 Patients reporting low energy or no energy at all, % 46.2 Nottingham Health Profile 47.0 score6 Second Evaluation* Third Evaluation? 0.342 0.339 44.53 43.5s 37.3$ 35.5s 45.4$ 48.1$ 23.23 22.2s 31.5f 27.71 * Approximately 6 months after initiation of rHuEpo therapy. t Approximately 10 months after initiation of rHuEpo therapy. 1 P 5 0.01 compared with baseline. 4 Scores, 100 = complete limitation; 0 = no physical limitation. withdrew because of possible toxicity, 5 had seizures, 2 had diffuse myalgias, 1 had a cardiac arrest, and 1 a decrease in vision. Of the 15 who voluntarily withdrew from therapy, 2 failed to respond to rHuEpo, 2 became hypertensive, and 2 developed headaches. Isolated causes comprised the balance. Miscellaneous non-toxicity-related reasons for withdrawal included protocol violation, 4 patients; moving to another location, 2 patients; and loss to follow-up, l patient. The mean age of the 22 patients who died was 60 f 4 years (range, 19 to 79). The causes of renal failure in these patients were diabetes mellitus in 10 patients; hypertension, 6 patients; chronic glomerulonephritis, 4 patients; and miscellaneous, 2 patients. The causes of death included myocardial infarction, arrhythmias, cardiopulmonary arrest in 11 patients; sepsis, 6 patients; cerebral hemorrhage, 2 patients (one from trauma); hyperkalemia, 1 patient; liver failure from hemochromatosis, 1 patient; and voluntary withdrawal from dialysis, 1 patient. The duration of rHuEpo therapy before death ranged from 26 to 329 days. Adverse Effects and Patient Management Issues The commonest adverse effect temporally related to rHuEpo administration was reported by 15 patients who had myalgias and a flu-like syndrome. These symptoms were usually mild. Two patients, however, discontinued rHuEpo therapy; in the other 13 patients these symptoms did not persist with continued admin996 15 December 1989 AnnalsofInfernalMedicine istration of rHuEpo, and they remained on therapy. Ten patients developed injected conjunctivae. In 25 1 patients there were sufficient data to evaluate changes in blood pressure and antihypertensive medications after 3 months of rHuEpo therapy. Of these patients, 88 (35%) developed an increase in the diastolic blood pressure of 10 mm Hg or more or required an increase in blood pressure medication or both within 3 months of rHuEpo therapy. Of the 251 patients, 180 (72%) had baseline hypertension and 57 (32%) had an exacerbation which required increased antihypertensive medication. Of the 71 patients who were not hypertensive before rHuEpo therapy, 31 (44%) had an increase in diastolic blood pressure of 10 mm Hg or more and 23 (32%) required initiation of antihypertensive treatment. Increase in blood pressure was thus unrelated to baseline levels. Seizures occurred in 18 of 333 (5.4%) patients. In ten instances, the seizure activity occurred within the first 3 months of rHuEpo therapy when the hematocrit was increasing and was sometimes related to the onset of uncontrolled hypertension. The risk of seizure in the total group of patients was 1 per 13 patient years. Of 333 patients, 142 (43%) who began treatment with rHuEpo developed evidence of absolute or functional iron deficiency as defined by a serum ferritin of less than 30 pg/L and a percent transferrin saturation of less than 20, or by a percent transferrin saturation less than 20 with a normal serum ferritin, respectively ( 2 ) . Despite receiving intravenous iron dextran (Imferon, Fisons Corporation, Bedford, Massachusetts) or oral iron medication, the serum ferritin often decreased, particularly during the acute phase of therapy, Serum ferritin levels decreased from a mean baseline value of 962 f 89 pg/L to 629 f 76 pg/L by the entry into the maintenance phase of the study (Table 1)The adequacy of dialysis was determined by following predialysis creatinine, blood urea nitrogen, phosphorus, and potassium concentrations. As seen in Table 3, there was a slight but statistically significant increase in predialysis serum creatinine, potassium, and phosphorus levels when the hematocrit increased as a result of rHuEpo therapy. Sixty thrombotic events involving vascular accesses were observed in a total of 39 patients, a rate of 0.3 thrombotic events per patient year. Most of the vascular accesses were polytetrafluoroethylene or bovine grafts. This incidence of access clotting is no greater than that observed in 1 1 1 1 patients on hemodialysis not treated with rHuEpo (0.5 clotting events/ patient . year; Downing M. Unpublished observations). Although the mean platelet count increased from 224 f 5 to 253 k 6 x lO9/L (P < 0.0005) during the acute phase, there was no further increase after 10 months of maintenance therapy (Table 1). Although statistically significant, the increase in platelet count was still within the normal range. Prothrombin and partial thromboplastin times and fibrinogen levels did not change over the course of rHuEpo theraPY. Volume 111 Number 12 Page 156 of 290 Discussion Severe chronic anemia is a major impediment to the rehabilitation of patients with end-stage renal disease. The major contributor to the anemia is a relative or absolute deficiency of erythropoietin production by the diseased kidneys. Although modest reductions in erythrocyte survival and putative inhibitors of erythropoiesis could contribute to the anemia, their effect cannot be great given the uniform and rapid response of essentially all patients on hemodialysis in clinical trials of rHuEpo. The results of this multicenter clinical trial involving 333 patients confirm the results reported by the smaller initial trials (2, 3, 8-14). A total of 323 patients have been previously reported from these other studies and all had significant erythropoietic responses to rHuEpo. Virtually all patients in this multicenter trial responded to rHuEpo in a dosedependent manner. Therapy with rHuEpo thus resulted in a correction of the anemia with achievement of target hemoglobin and hematocrit levels for more than 97% of patients, virtual elimination of the need for erythrocyte transfusions, and the reduction of iron overload, if present. In addition, in response to a series of questionnaires, patients reported significant increases in their energy and activity levels and health status, resulting in a substantial improvement in their quality of life (15). Doses of rHuEpo required to maintain the hematocrit at 0.35 & 0.03 varied from 12.5 to 525 U/kg, but 83% of the patients required 150 U/kg or less. The reason why a small percentage of these patients (17%) required higher doses of rHuEpo in order to maintain a stable hematocrit is unknown. Therapy with rHuEpo was well tolerated and many of the adverse effects of drug administration are likely coincidental. Among the direct adverse effects which were noted most frequently, myalgias or flu-like syndrome or both, infected sclera, headache, and flank pain were the most prominent. These symptoms have been reported previously in association with rHuEpo therapy (3, 9, 16). Whereas we observed a 5% incidence of flu-like myalgias, 17% incidence of headaches, and a 14% incidence of flank pain, the European Cilag multicenter trial using the same rHuEpo observed a 770, 2770, and 30% incidence of these adverse effects, respectively (17). The role of rHuEpo in these complaints is uncertain but, they were generally mild and usually did not persist nor preclude continued treatment with, or an effective response to the drug. Therapy with rHuEpo had no detectable adverse organ effects during the course of this trial. Liver function remained unchanged and cholesterol and triglyceride levels, blood glucose, serum calcium, and serum albumin levels did not change with rHuEpo therapy. The overall prorated yearly mortality rate for the patients on study was 9.4%, which is slightly less than the first-year mortality rate (12%) observed for US. patients on dialysis ages 45 to 54 years during 1983 through 1986 (18). These results clearly show that rHuEpo is effective 15 December 1989 in correcting the anemia of hernodialysis patients and that few, if any, side effects can be directly attributed to its use. Equally important is the fact that antibodies have not developed against the recombinant protein. Three of the five major issues of patient management-hypertension, seizures, and functional-absolute iron deficiency-were confirmed and detailed by the present study. Hypertension is a frequent complication of chronic renal failure; hypertension was the major mechanism that resulted in renal failure in 23% of the study patients. In this clinical trial 35% of all patients developed an increase in blood pressure which was defined as an increase in diastolic blood pressure of 10 mm Hg or more, whereas 25% of the patients required initiation or increase in antihypertensive medication. Although 72% of the rHuEpo-treated patients had existing hypertension at baseline, they were at no greater risk for exacerbation of hypertension than those patients who were not originally hypertensive (32% and 32%, respectively). Blood pressure increased at a similar incidence in patients receiving 150 or 3 0 0 U/kg as the initial doses of rHuEpo. In a few instances, hypertensive crises were associated with seizure activity. Careful monitoring and control of blood pressure in rHuEpo-treated patients, particularly during the acute phase of treatment, is essential. Some patients will require more antihypertensive medication than others as their anemia is being corrected. The development or exacerbation of hypertension in patients on hemodialysis responding to rHuEpo is probably caused by a reversal in the peripheral arteriolar vasodilation that occurs with anemia. Preliminary data from several groups suggest that the increased hematocrit results in a decrease in peripheral vasodilation with an increase in total peripheral resistance (19, 20). These observations are consistent with earlier studies by Neff and coworkers (21). They studied six hemodialysis patients who were transfused to a hematocrit of 0.40 over a 2-week period and noted that correction of the anemia (that is, a doubling in the hematocrit) was associated with a twofold increase in peripheral vascular resistance as well as a decrease in cardiac index. Although increased seizure activity is well recognized among patients with end-stage renal disease, the precise frequency in patients similar in age, sex, and clinical status to those in the rHuEpo study is not known. The incidence of seizure activity in 1 1 1 1 patients not treated with rHuEpo was 8% (Downing M. Unpublished observations), which is similar to that observed in those patients receiving rHuEpo. Approximately 50% of the seizures in rHuEpo-treated patients occurred during the initial 12 weeks when the anemia was being corrected. Although not statistically significant, it is possible that the frequency of seizures seen during this period in this study exceeds that of the background seizure activity in the end-stage renal disease population in general. Whether or not this is true, it is clear that careful monitoring of blood pressure and control of hypertension will be an important management issue as rHuEpo becomes available for routinely treating anemia in patients with end-stage renal disease. Annals ofZnternalMedicine Volume 1 1 1 Number 12 997 Page 157 of 290 Table 3. Effectof Recombinant Human Erythropoietin on Biochemical Values -- Solutes Creatinine, ,umol/L (mddL) Blood urea nitrogen, mmoII/L (mg/dl;) Potassium, mmol/L (mEg/L) Bicarbonate, mmoI/L (mEq/L) Uric acid, p n o l / L (mg/dL) Albumin, g / L WdL) Phosphorus, mmoI/L fm,ddL) 1167 (13.2) 18 (0.2) 28.8 (80.8) 0.4 (1.2) 5.1 (5.1) 0.04 (0.04 20.7 (20.7) 0.2 (0.2) 393 (6.6) 0.59 (0.1) 38.0 (3.8) 0.3 (0.03 1.78 (5.5) 0.03 (0.1) * Compared with baseline, using paired t-test. NS 298 298 297 296 241 260 292 15 December 1989 P Value+ 298 < 0.0005 298 0.0 14 297 0.012 296 < 0.0005 24 1 < 0.0005 260 0.002 292 < 0.0005 = not significant. A third management issue involves the availability of iron for rHuEpo-stimulated erythropoiesis, particularly during the treatment-induction phase, as the hematocrit is rising. Functional or absolute iron deficiency occurred in 43% of all patients during the early treatment phase. The incidence of iron deficiency would have been greater if 20% of the patients had not been iron overloaded. Studies from one of our centers suggest that most severely anemic patients on hemodialysis treated with rHuEpo will eventually require supplemental iron unless their baseline serum ferritin is greater than lo00 pg/L (22). Iron deficiency, whether relative or absolute, will reduce the effectiveness of rHuEpo and unnecessarily add to the cost of treatment and delay rehabilitation of the patient. Furthermore, iron deficiency may lead to confusion about the responsiveness of the patient to the drug. On the basis of our experience of the phase I11 clinical trial, we feel that transferrin saturations of less than 20% indicate impaired iron availability for hemoglobin synthesis and suggest the need for either oral or intravenous iron replacement. If use of oral iron supplementation does not maintain a percent saturation greater than 20, intravenous iron dextran may be required periodically for optimal erythropoiesis. Underdialysis and an increase in clotting of arteriovenous grafts at higher hematocrits were potential (23), but unproven, concerns. As noted in Table 3, the mean predialysis creatinine values, although statistically significantly higher, were only 4.5% higher after the hematocrit had increased from 0.22 to 0.34. Although dialyzer clearance of creatinine decreases as the hematocrit rises (24), the magnitude of this change did not result in a need to either lengthen dialysis times or increase dialyzer membrane surface area. The mean blood urea nitrogen values did not increase, consistent with the data that suggest that urea diffuses instantly from the erythrocyte and that urea clearance is not altered by a change in the hematocrit (25). Predialysis serum phosphate levels also increased slightly, but significantly. Although dialyzer clearance of phosphate may decrease as dialyzer plasma volume de998 1220 (13.8) 27 (0.3) 27.7 (77.5) 0.5 (1.4) 5.2 (5.2) 0.06 (.06 19.0 (19.0) 0.2 (0.2) 434 (7.3) 0.43 (0.1) 39.0 (3.9) 0.3 (0.03 2.03 (6.3) 0.06 (0.2) Number of Patients Annals ofznternafMedicine creases, it is not clear what role that increased dietary phosphate may have contributed to the observed change. Serum potassium levels did increase minimally, but significantly. The small change seen could be contributed by any combination of increased dietary intake, decrease in dialyzer clearance, or increased erythrocyte potassium release, because the increased erythrocyte mass will release proportionately more potassium at the time of erythrocyte death. Although the clinical significance of slight increases in predialysis serum creatinine and phosphate concentration is probably minimal, the effects of hyperkalemia are of greater concern. Serum potassium levels should be monitored carefully in all patients and potassium should be eliminated from the dialysate if medically indicated. In this multicenter trial, 39 patients experienced 60 thrombotic events that involved the arteriovenous access, most of which were polytetrafluoroethylene grafts. When these events were corrected for the total number of patients responding to rHuEpo, 12% of patients per year experienced clotting in their vascular access. In previous studies of hemodialysis patients not receiving rHuEpo, polytetrafluoroethylene arteriovenous grafts were associated with a greater frequency of thrombosis than was observed in natural (Cimino) fistulae (26, 27). These authors reported that 49% and 29% of 163 and 219 patients, respectively, had recurrent polytetrafluoroethylene graft failure, primarily due to thrombosis requiring surgical revisions every 0.5 years. Therefore, there is a subgroup of patients not treated with rHuEpo who clot their arteriovenous grafts an average of one to two times per year. In addition, in another survey (Downing M. Unpublished data), the incidence of access clotting in over lo00 hernodialysis patients not treated with rHuEpo was approximately twice the incidence of access clotting in our study. Therefore, we feel that rHuEpo treatment does not increase the incidence of vascular access clotting. There was no increase in cerebrovascular, coronary or peripheral arterial thromboses when compared to over lo00 hemodialysis patients not treated with rHuEpo (Downing M. Unpublished Volume 111 Number 12 Page 158 of 290 Table 3. (Continued) 6 Months (fSE) 1246 (14.1) 27 (0.3) 29.4 (82.4) 0.5 (1.5) 5.2 (5.2) 0.05 (0.05) 18.7 (18.7) 0.3 (0.3) 428 (7.2) 0.43 (0.1) 39.0 (3.9) 0.3 (0.03) 1.91 (5.9) 0.03 (0.1) Number of Patients Maintenance P Value* 224 0.0013 224 NS 225 0.003 222 < 0.0005 177 < 0.0005 189 NS 220 < 0.0005 data.) Three centers noted an increased need for heparin in some patients with near-normal hematocrit levels to adequately clear the dialyzer at the end of dialysis; this problem was easily managed by increasing the primary dose of heparin by lo00 units. Patients who previously required transfusions became transfusion-independent with the advent of rHuEpo therapy. If this group of patients is representative of patients with end-stage renal disease as a whole, the savings in blood nationally would be projected to be 500 OOO units a year. This figure is based on the fact that the mean transfusion need per month for the patients in this clinical trial was 0.52 and assumes that all patients with end-stage renal disease who required transfusions will receive rHuEpo, that all patients will respond and become transfusion-independent, and that the patients in this study are representative of the approximately 75% of the 100 OOO patients with end-stage renal disease in the United States who are candidates for rHuEpo therapy. The alleviation of transfusion requirements will have not only a positive effect on the nation’s blood supply, but also on nursing time, on the potential exposure of patients and health personnel to infection, the risks of iron overload in selected patients, and the number of potential kidney transplant recipients since there will be less transfusion-induced sensitization. Use of rHuEpo had no predictable effect on other hematopoietic lineages; its major effect appears to be specific for erythropoiesis. Nevertheless, the mean platelet count in patients treated with rHuEpo rose significantly. Whether this reflects a minor effect of rHuEpo on megakaryocyte maturation and platelet production, as has been reported previously (8, 11, 16, 28, 29), is not known. It is equally conceivable that some patients who developed either absolute or relative iron deficiency during the course of rHuEpo therapy also developed reactive thrombocytosis. Thus, iron deficiency might account for the marginal increase in platelet count but would not be considered a direct effect of the hormone on megakaryocytopoiesis. The effect of rHuEpo on the quality of life of pa15 December 1989 10 Months (*SE) Number of 1299 (14.7) 35 (0.4) 31.1 (87.0) 0.8 (2.3) 5.4 (5.4) 99 0.04 99 NS 99 0.001 99 < 0.0005 81 0.009 74 NS 98 0.037 .08 (0.08) 18.4 (18.4) 0.3 (0.3) 410 (6.9) 0.41 (0.2) 40.0 (4.0) 0.4 (0.04) 1.91 (5.9) 0.03 (0.2) P Value* Patients tients with end-stage renal disease is most impressive when the objective variables of functional ability, energy level, and health status are assessed. Of the previous studies (6) of quality-of-life assessments in endstage renal disease patients, none has documented a treatment intervention (other than transplantation) that enhances quality of life to the magnitude as that achieved by rHuEpo. The results of the phase I11 clinical trial with rHuEpo in patients with anemia and end-stage renal disease have been evaluated and the initial conclusions of the phase 1-11 clinical trials have been confirmed. Recombinant human erythropoietin is effective, safe, and well tolerated. We recommend that rHuEpo become standard therapy in the management of anemic patients with end-stage renal disease and believe it will contribute to the rehabilitation and improved health status of these patients. Acknowledgments:The authors thank the registered nurses who coordinated, the staff who administered the study, and the patients who volunteered for the study. Grant Support: Supported in part by Amgen. Inc., Thousand Oaks, California. Requests forRephts: Michael Downing, PhD, Amgen, Inc., 1900 Oak Terrace Lane, Thousand Oaks, CA 91320. Current Author Addresses: Drs. Exhbach and Haley: Division of He- matology, RM-10, Department of Medicine, University of Washington, Seattle, WA 98195. Drs. Abdulhadi and Paganini: Section of Dialysis and Extracorporeal Therapy, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44106. Drs. Browne, Downing, and Egrie: Amgen, Inc., 1900 Oak Terrace Lane, Thousand Oaks, CA 9 1320. Drs. Delano, Friedman, and Lundin: Division of Renal Disease, Department of Medicine, State University of New York Health Science Center at Brooklyn, 470 Clarkson Avenue, Box 52, Brooklyn. NY 11203. Dr. Evans and Ms. Rader: Battelle, Human Affairs Research Center, P.O. Box C-5395, 4ooo N.E. 41st Street, Seattle, WA 98105. Drs. Graber and Krantz: Division of Hematology, Department of Medicine, Vanderbilt University, Nashville, TN 37232. Dr. Korbet: Section of Nephrology, Department of Medicine, RushPresbvterian-St. Luke’s Medical Center. 1653 West Congress - Parkwav. chicigo. IL 60612. Dr. Nissenson: Division of Nephrology, Department of Medicine, UCLA School of Medicine, Los Angeles, CA 90024. Drs. Ogden and Van Wyck: Department of Internal Medicine, Section of AnnalsofZnternalMedicine Volume 111 Number 12 999 Page 159 of 290 Renal Disease, The University of Arizona Health Sciences Center, Tucson, AZ 85724. Dr. Rutsky: University of Alabama at Birmingham, Department of Medicine/Division of Nephrology, Birmingham, AL 35294. Dr. Stivelman: Department of Medicine, Emory University School of Medicine, 69 Butler Street, S.E., Atlanta, GA 30303. Drs. Stone and Teschan: Nashville Veterans Affairs Medical Center, 1310-24th Avenue, South, Nashville, T N 37212. Dr. Van Stone: Department of Medicine, Division of Nephrology, University of Missouri Medical School, 18005 E. Walnut, Columbia, MO 65212. Dr. Zuckerman: University of Alabama at Birmingham, Division of Hematology/Oncology. Department of Medicine, Birmingham, AL 35294. Dr. Adamson: The New York Blood Center, 310 East 67th Street, New York. NY 10021. References 1. Eschbach JW, Adamson JW. Anemia of end-stage renal disease (ESRD). Kidney Int. 1985;281-5. 2. Eschbach JW, Egrie JC, Downing MR, Browne JK, Adamson JW. Correction of the anemia of end-stage renal disease with recombinant human erythropoietin. N f i g 1 JMed. 1987;31673-8. 3. Winearls GC, Oliver DO, Pippard MJ, Reid C, Downing MR, Cotes PM. Effect of human erythropoietin derived from recombinant DNA on the anaemia of patients maintained by chronic haemodialysis. Lancet. 1986;2:1175-8. 4. Lin FK, S u m S , Lin CH, et al. Cloning and expression of the human erythropoietin gene. Proc Natl Acad Sci USA. 1985;82:75805. 5. Egrie JC, Strickland TW,Lane J, et al. Characterization and biological effects of recombinant human erythropoietin. Immunobioiogy. 3986;172:233-24. 6. Evans RW, Manninen DL, Garrison L P Jr, et al. The quality of life of patients with end-stage renal disease. N Engl J Med. 1985;312:553-9. 7. Hunt SM, McEwen J, McKenna SP. Measuring Health Status. London; Croom Helm; 1986. 8. Bommer J, Alexiov C, Muller-Buhl E, Eifer J, Ritz E. Recombinant human erythropoietin therapy in haemodialysis patients-dose determination and clinical experience. Nephrol Dial Transplant. 1987;2:238-42. 9. Casati S , Passerini P, Campise MR, et al. Benefits and risks of protracted treatment with human recombinant erythropoietin in patients having haemodialysis. Er Med J [Clin Re]. 1987;295:101720. 10. Eschbach JW, Adamson JW. Recombinant human erythropoietin: implications for nephrology. A m J Kidney Dis. 1988;11:203-9. 11. Bommer J. Kugel M, Schoeppe W, et al. Dose-related effects of recombinant human erythropoietin on erythropoiesis. Results of a multicenter trial in patients with end-stage renal disease. Contn'bu Nephrol. 1988;66:85-93. 12. Schaefer RM, Kuerner B, Zech M, Denninger G, Borneff C, Heidland A. Treatment of the anemia of hemodialysis patients with recombinant human erythropoietin. Inf J Artif organs. 1988;11:249- 1000 15 December 1989 Annals oflnternalMedicne 54. 13. Akimwa T, Koshikawa S , Takaku F, et al. Clinical effect of recombinant human erythropoietin on anemia associated with chronic renal failure. A multi-institutional study in Japan. Znt JArtif Organs. 1988;11:343-50. 14. Mayer G, Thumm J, Cada EM, Stummvoll HK, Graf H. Working capacity is increased following recombinant human erythropoietin treatment. Kidney Int. 1988;34525-8. 15. Evans RW, Rnder B, Manninen DL, and the Cooperative Multicenter E P O Clinical Trial Group. The quality of life of hemodialysis patients treated with recombinant human erythropoietin. JAMA. [In press]. 16. Grutzmacher P, Bergmann M, Weinreich T, Nattermann U, Reimers E, Pollok M. Beneficial and adverse effects of correction of anaemia by recombinant human erythropoietin in patients on maintenance haemodialysis. Contrib Nephrol. 1988;66104-13. 17. Sundal E, Kaeser U. Correction of anaemia of chronic renal failure with recombinant human erythropoietin: safety and efficacy of one year treatment in a European multicenter study in 150 haemodialysis-dependent patients. Nephrol Dial & Transplant. [In press]. 18. Health Care Financing Administration: End-stage renal disease research report, 1987. 19. Buckner FS, Eschhach JW, Haley NR, Davidson RR, Adamson JW. Correction of the anemia in hemodialysis ( H D ) patients (PTS) with recombinant human erythropoietin (rHuEpo): hemodynamic changes and risks for hypertension. [Abstract]. Kidney Int. 1989;35:190. 20. Nonnast-Daniel B, Creutzig A, Kuhn K, et al. Effect of treatment with recombinant human erythropoietin on peripheral hemodynamics and oxygenation. ConfribNephrol. 1988;66185-94. 21. Neff MS, Kim KE, Persoff M, Onesti G, Swartz C. Hemodynamics of uremic anemia. Circulation. 1971;43:876-83. 22. Van Wyck DB, Stivelman JC, Ruiz J, Kirlin LF, Katz MA, Ogden DA. Iron status in patients receiving erythropoietin for dialysis-associated anemia. Kidney Int. 1989;35:712-6. 23. Shinaberger J H , Miller J H , Gardner PW. Disadvantages and risks of normal hematocrit hemodialysis [Abstract]. Kidney Inf. 1989;35:264. 24. Babb AL, Popovich RP, Farrell PC, Blagg CR. The effects of erythrocyte mass transfer rates on solute clearance measurements during haemodialysis. Proc Eur Dial Transplant A s m . 1972;9303-2 1. 25. Cheung AK, Alford MF, Wilson MM, Leypoldt JK, Henderson LW. Urea movement across erythrocyte membrane during artificial kidney treatment. Kidney Int. 1983;23866-9. 26. Palder SB, Kirkman RL, Whittemore AD, Hakim RM, Lazarus J M , Tihey NL. Vascular access for hemodialysis. Patency rates and results of revision. Ann Surg. 1985;202235-9. 27. Schuman ES. Gross GF, Hayes JF, Standage BA. Long-term patency of polytetrafluoroethylene graft fistulas. A m J Surg. 1988;155 644-5. 28. Ishibachi T, Koziol JA, Burstein SA. Human recombinant erythropoietin promotes differentiation of murine megakaryocytes in vitro. J Clin Invest. 1987;79286-9. 29. Stone WJ, Graber SE, Krantz SB, et al. Treatment of the anemia of predialysis patients with recombinant human erythropoietin: a randomized, placebo-controlled trial. A m J Med Sci. 1988;296: 171-9. Volume 11 1 Number 12 Page 160 of 290 Kidney International, Vol. 55, Suppl. 69 (1999), pp. S-35–S-43 Iron overload in renal failure patients: Changes since the introduction of erythropoietin therapy JOSEPH W. ESCHBACH and JOHN W. ADAMSON University of Washington, Minor and James Medical, Seattle, Washington, and Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, USA Iron overload in renal failure patients: Changes since the introduction of erythropoietin therapy. Iron overload was a common complication in patients with chronic renal failure treated with dialysis prior to the availability of recombinant human erythropoietin (rHuEPO) therapy. Iron overload was the result of hypoproliferative erythroid marrow function coupled with the need for frequent red blood cell transfusions to manage symptomatic anemia. The repetitive use of intravenous iron with or without the use of red blood cell transfusions also contributed to iron loading and was associated with iron deposition in liver parenchymal and reticuloendothelial cells; however, there were no abnormal liver function tests or evidence of cirrhosis unless viral hepatitis resulted from the transfusions. With rHuEPO therapy, the excess iron stores were shifted back into circulating red blood cells as the anemia was partially corrected, and red blood cells were lost from circulation by the hemodialysis procedure. After several years of rHuEPO therapy, most hemodialysis patients required iron supplements to replace the continuing blood losses related to hemodialysis. The potential complications of iron overload (parenchymal iron deposition, permanent organ damage, increased risk of bacterial infections, and increased free radical generation) are reviewed in the context of this setting. mias [4], including the anemia of chronic renal failure (CRF) [5–7] or from the repetitive injection of parenteral iron. Hemosiderosis is also referred to as secondary iron overload. Traditionally, hemochromatosis and hemosiderosis have been separated by the concept that in the former, the iron overload is primarily in tissue parenchymal cells leading to organ dysfunction and eventually organ failure, whereas in hemosiderosis, the iron is limited to the RE cell, with no organ dysfunction or failure. However, in hemosiderosis, these lines of separation may not always be that precise, as noted in a review of iron overload in various conditions [8], particularly that of CRF [9]. In order to appreciate the changes that recombinant human erythropoietin (rHuEPO) has made on the ironoverload complication in CRF, it is important to understand what impact, if any, iron overload has had on the overall health of dialysis patients. IRON PHYSIOLOGY Iron stores in normal subjects vary between approximately 800 mg to 1200 mg, depending on body size [1], although phlebotomy studies suggest that normal iron stores may be as high as 1200 to 1500 mg [2]. Primary iron overload, or primary hemochromatosis, is a common hereditary disorder in which excessive amounts of iron are absorbed from the gastrointestinal tract, resulting over many years in the accumulation of massive amounts of iron (as much as 20 to 40 g) in the parenchymal cells of various tissues, leading to end-organ damage to the heart, liver, and pancreas [3]. Hemosiderosis is the accumulation of excess iron, primarily in the reticuloendothelial (RE) cells of the liver, marrow, and spleen, as the result of the repetitive infusion of iron from red blood cell (RBC) transfusions for the treatment of severe aneKey words: chronic renal failure, blood, rHuEPO, anemia, dialysis. 1999 by the International Society of Nephrology The amount of iron in excess of normal iron stores required to develop hemosiderosis is not known, but probably is considerable. One estimate is that the storage limit of macrophages is exceeded after the accumulation of 5 g of unexcretable iron [8]. An understanding of iron transport and kinetics is essential in order to comprehend the issue of “iron overload.” This is particularly true since the introduction of rHuEPO therapy, which has changed our understanding of iron metabolism and its management in CRF. Iron that is absorbed from the gastrointestinal tract is transported in circulation to either the erythroid marrow, RE cells, or various tissues (for example, myoglobin in muscle cells or liver in severe iron overload) by the protein transferrin. Iron that is injected intravenously, either as RBCs or as an iron compound (iron dextran, ferric gluconate, or ferric saccharate), is processed by the RE cell and then transported on one or both ironbinding sites of the transferrin molecule to either the S-35 Page 161 of 290 S-36 Eschbach and Adamson: Iron overload in renal failure erythroid marrow or to various other tissues. The likelihood that nonerythroid tissues will take up transferrinbound iron is determined by the activity of the erythroid marrow and by the degree of saturation of transferrin. Transferrin receptors are probably expressed on all cells, with the exception of mature RBCs, with the highest expression of receptors on hemoglobin-synthesizing cells [10]. One of the few ferrokinetic studies in hemodialysis patients not treated with rHuEPO noted that the nonerythroid iron turnover was directly related to serum iron levels and with the percentage transferrin saturation, with serum iron values of more than 150 mg/dl, and transferrin saturations of more than 60% associated with a nonerythroid iron turnover of more than 0.4 mg/100 ml whole blood/day (normal 5 0.16; Fig. 1). This suggests that when the transferrin saturation is more than 60% and the serum iron is greater than 150 mg/dl, the likelihood of transferrin-bound iron being shunted to nonerythroid cells is increased in the anemic dialysis patient not treated with rHuEPO. In the anemic patient treated with rHuEPO, erythropoiesis is stimulated, and more iron will be preferentially taken up by the erythroid marrow, reducing the likelihood of iron deposition in nonerythroid tissues and mobilizing stored iron in order to support new hemoglobin synthesis. IRON OVERLOAD IN CRF PRIOR TO ERYTHROPOIETIN THERAPY To appreciate the effect that rHuEPO treatment has had on iron overload in anemic CRF patients, it is necessary to understand what the experience was with iron overload prior to the introduction of rHuEPO therapy. Prior to the availability of rHuEPO therapy in CRF, iron overload was very common. The natural progression of the anemia of CRF results in a gradual shift of red cell iron into storage sites in the RE system (RES) so that by the time patients start dialysis, if not treated with rHuEPO, they are often severely anemic (hematocrit 15% to 25%/hemoglobin 5 to 8 g/dl). If external blood losses have not occurred, then the iron, previously part of the RBC mass, becomes sequestered in the RES, resulting in elevated serum ferritin levels even in those patients who have not received any exogenous iron. The anemia of CRF is primarily due to insufficient production of renal erythropoietin. Recently, erythropoietin has been shown to increase transferrin receptor synthesis and cell surface expression in erythroid cells by activating the iron regulatory protein 1, thus stabilizing transferrin receptor mRNA [11]. Without sufficient erythropoietin stimulation of the erythroid cell, the number of erythroid cell surface transferrin receptors is probably down-regulated, increasing the likelihood of iron uptake by nonerythroid tissues, including the liver. As reflected by in vivo organ counting following 59Fe Fig. 1. The amount of nonerythroid iron turnover in patients on chronic hemodialysis related to their serum iron values (A) and percentage transferrin saturation (B; unpublished observations). administration in dialysis patients, iron deposition often occurred in the liver when erythroid marrow function was severely depressed [9]. Liver biopsies in these patients disclosed iron in both hepatocytes and Kupffer cells (the RE cell of the liver) [9]. Because of the persistent anemia, RBC transfusions were often necessary. Gradually, as more RBC transfusions were given and iron intake exceeded iron losses, the transferrin saturation and serum ferritin levels increased, and as the transferrin saturation rose, iron was delivered in increasing amounts to the liver and the parenchymal cells of other tissues, including heart, thyroid, and pancreas. This ultimately led to evident tissue iron overload, as demonstrated by bone marrow and liver biopsy and autopsy studies [6, 7, 9, 12–19]. Some individuals eventually had transferrin saturations and serum ferritin levels exceeding 80% and 4000 ng/ml, respectively. However, this was not necessarily an irreversible process. Some dialysis patients had enough erythroid marrow function to not require RBC transfusions and did not shunt unincorporated RBC iron into the liver [9]. Occasionally, erythropoiesis in some dialysis patients spontaneously improved [9], particularly if RBC transfusions were avoided. Red cell transfusions in these patients had resulted in further suppression of the small amount of renal erythropoietin that was being produced [20]. If, and when, erythropoiesis improved in these patients, iron overload gradually was Page 162 of 290 Eschbach and Adamson: Iron overload in renal failure reduced because of the elimination of RBC transfusions coupled with the ongoing blood losses related to the hemodialysis procedure. Prior to rHuEPO therapy, there evolved the practice of not transfusing except when there was symptomatic tissue hypoxia. Most patients without angina could slowly adjust to a hematocrit of 22% to 28% and not require RBC transfusions, although energy levels and quality of life were diminished. Nevertheless, although hemodialysis-related iron (blood) losses were often large (1 to 3 g/year) [21–23], these losses frequently did not compensate for the amount of iron previously received from RBC transfusions. Therefore, iron overload persisted. Attempts to reduce iron overload with desferrioxamine were successful primarily in those patients who no longer required RBC transfusions. However, in the majority of patients, the amount of iron chelated and transferred across the dialyzer membrane was less than the amount of iron received intravenously through ongoing RBC transfusions [24–28]. Although no recent studies of dialyzer blood losses have been published, we believe there are still substantial iron losses occurring even with the newer dialyzers. For instance, during 1994, 75% of the 615 hemodialysis patients at the Northwest Kidney Centers (Seattle, WA, USA) received 0.5 to 3.0 g (1.0 6 0.6 g, mean 6 sd) of iron dextran i.v., despite ingesting oral iron, just to maintain serum ferritin levels and transferrin saturations close to 100 ng/ml and 20%, respectively (J. W. Eschbach, R. Garth, and C. R. Blagg, unpublished results). Iron overload also has occurred as the result of the excessive administration of parenteral iron. Most studies of iron overload in dialysis patients have included patients who have received both parenteral iron as well as RBC transfusions [12, 14, 16, 17, 27, 29–31]. There has been only one report of iron overload in dialysis patients caused by intravenous iron infusions without any RBC transfusions: Two groups of dialysis patients with iron overload were studied. One group received repeated injections of parenteral iron. The other group received multiple RBC transfusions [32]. The serum ferritin levels ranged from just below 1000 ng/ml up to 3000 ng/ml in the parenteral iron group and less than 1000 ng/ml in the transfused group. Although iron was present in both hepatocytes and Kupffer cells on liver biopsies in some patients, the authors did not attempt to determine if the liver cell iron deposition was different between the two groups. Iron overload also has been reported in a subject with normal renal function who received 52 g of elemental iron intramuscularly over a 20-year period for treatment of an ill-defined anemia [33]. The serum ferritin was 2840 ng/ml, and liver function tests were normal. Despite the fact that liver biopsy disclosed large deposits of iron in the parenchyma with minimal iron deposition in the Kupffer cells, there was no cirrhosis. The distinction between iron given parenterally and S-37 iron given as RBC transfusions may be a critical one. The hemosiderosis from iron overload secondary to RBC transfusions may be complicated by the presence of hepatitis B or C acquired in the course of being transfused [16]. Hepatocellular injury from hepatitis C may favor iron deposition in liver parenchymal cells [34]. Because serological testing for hepatitis C was not available during the pre-rHuEPO era when RBC transfusions were common therapy for the anemia of CRF, it is difficult to determine the relative contributions of hepatitis and iron deposition to the abnormal liver biopsy/autopsy findings and other liver tests performed. Parenteral infusion of iron, in various forms, has been studied extensively in animals. The amount of iron these animals received in different studies ranged between 0.1 and 3.3 g/kg with a follow-up between four weeks and seven years [35, 36]. Despite these large infusions of iron (up to 17 g), the kind of parenchymal tissue changes seen in primary hemochromatosis has not been observed; that is, cirrhosis and pancreatic fibrosis have not been found, and tests of liver and cardiac function and of glucose tolerance have remained normal. The large amounts of iron were predominantly sequestered in RE cells without any fibrotic reaction present. IRON OVERLOAD IN CRF SINCE rHuEPO THERAPY There are no good epidemiological data to indicate the magnitude of iron overload prior to the availability of rHuEPO, but it must have been common. Approximately 50% of dialysis patients in one study required more than one RBC transfusion monthly [37]. One center noted that 64 of its 120 hemodialysis patients had serum ferritin levels of more than 1000 ng/ml [17]. The longer patients survived and were transfused, the greater the likelihood that iron overload would develop. The introduction of rHuEPO has resulted in major benefits for the patient with the anemia of CRF. One of these has been the elimination of the need for routine RBC transfusions and the eventual elimination of iron overload. Many studies have demonstrated that serum ferritin levels decrease abruptly with the use of rHuEPO in CRF [38–40], as well as in normal subjects [41]. This results from the mobilization of storage iron for incorporation into newly synthesized hemoglobin. Further depletion of iron stores occurs in the hemodialysis patient, particularly, because of continued dialyzer-related blood losses [21–23]. Several investigators have shown that iron overload could be reduced more rapidly if periodic phlebotomy were performed in association with rHuEPO therapy [13–15, 19]. We noted that of the original 23 hemodialysis patients treated with rHuEPO [37], 17 were still receiving rHuEPO three years later [42]. Many of these patients originally had iron overload, as arbitrarily Page 163 of 290 S-38 Eschbach and Adamson: Iron overload in renal failure These concerns relate to the following possible complications: (a) parenchymal cell involvement with or without organ dysfunction, (b) permanent organ damage, that is, cirrhosis and/or pancreatic fibrosis, cancer, or myocardial infarction, (c) increased risk of bacterial infections, and (d) increased free radical generation from free iron causing increased oxidant-mediated tissue injury. None of these concerns has been proven, but because iron therapy is so essential to the optimum effectiveness of rHuEPO, it is appropriate to review these concerns in relation to the extensive degree of iron overload in the pre-rHuEPO era and whether these complications might develop today if the use of intravenous iron were more routine and poorly monitored. Fig. 2. Decline in serum ferritin levels during three to four years of rHuEPO therapy in 17 hemodialysis patients [42]. Symbols are: (s) iron excess, N 5 6; (d) normal stores, N 5 11. defined by a serum ferritin of more than 1000 ng/ml (mean 6 sd serum ferritin 1073 6 956 ng/ml). After three years of rHuEPO therapy, all 17 had normal or low serum ferritin levels (186 6 196 ng/ml; Fig. 2), and 15 required supplemental iron therapy [41]. Today, very few dialysis patients have iron overload unless they continue to require RBC transfusions and/or are unable to be treated with rHuEPO. Iron deficiency is now far more common than iron overload as a result of the combined significant dialyzer-related blood losses and the stimulating effect of rHuEPO on hemoglobin synthesis. As recently as 1996, the United States Renal Disease System’s Dialysis Morbidity and Mortality Study noted that more than 50% of 2613 dialysis patients in 1993 had transferrin saturation values of less than 20%, and 36% had serum ferritin levels of less than 100 ng/ml [43]. Because of the need to correct iron deficiency and to maintain iron stores in the dialysis patient treated with rHuEPO, iron supplementation is required, and iron given intravenously accomplishes this task much better than does oral iron [40]. ADVERSE EFFECTS OF CHRONIC IRON OVERLOAD IN CRF There has been much concern raised about the potential toxicity of chronic iron exposure in dialysis patients. Parenchymal iron deposition In one report of chronically anemic adults with normal renal function, multiple RBC transfusions resulted in iron overload. These patients had evidence of hepatomegaly with iron in both the hepatocytes and Kupffer cells on liver biopsy [4]; however, cirrhosis was not observed except in one patient with a prior history of hepatitis. A similar pattern was observed in another anemic subject (with normal renal function) who received excessive amounts of intramuscular iron [33]. Cirrhosis also failed to develop after chronic parenteral iron administration to dogs, although the iron deposits were localized in the RE cells and not the parenchyma [35]. Iron overload in hemodialysis patients has resulted in increased iron deposition in liver parenchymal cells as well as the Kupffer cells [9]. Cirrhosis was observed primarily in iron-overloaded patients who had a history of hepatitis B, or perhaps hepatitis C, but there was no way to document the latter disease at that time. Iron overload in hemodialysis patients has also been associated with a proximal myopathy [45]. Ten patients had proximal muscle weakness and serum ferritin levels of 1030 to 5000 ng/ml. Proximal muscle biopsies (in seven of 10 patients) disclosed iron deposition in muscle fibers (five of seven) and macrophages (six of seven). However, there was no evidence of muscle injury or inflammation, and the amount of iron deposition did not correlate with the severity of muscle weakness. All of these patients had one or more of the “hemochromatosis alleles,” that is, HLA3, B7, or B14. The authors suggested that patients with the hemochromatosis alleles are at increased risk to develop iron overload and muscle iron deposition. Because primary hemochromatosis is a very common inherited metabolic disorder (1 in 300 whites being homozygous and 1 in 10 being heterozygous) [46], it would be expected that among the thousands of dialysis patients, many would either have the disease or be a carrier of the gene for this disorder. One theory is that these patients would lack the regulatory mechanism that prevents iron absorption in the presence of adequate iron Page 164 of 290 Eschbach and Adamson: Iron overload in renal failure stores, and this would result in the preferential deposition of iron in parenchymal cells, rather than the RES. A report from Italy suggested that dialysis patients that had one or more of these three hemochromatosis alleles were more prone to develop iron overload from RBC transfusions than those patients without any of these HLA antigens [47]. However, another report failed to confirm a correlation between the presence of hemochromatosis alleles in CRF and iron overload [48]. There are a number of problems with this concept: (a) Only one center has reported excess iron in muscle cells, and even that study noted that the myopathy was out of proportion to the amount of iron present. (b) Myopathy is not a prominent complication of primary hemochromatosis or hemosiderosis in nondialysis patients, and (c) patients heterozygous for hemochromatosis do not absorb excessive amounts of iron. Permanent organ damage In dialysis patients with hemosiderosis, there have been no reports of cirrhosis, pancreatic fibrosis, or cardiac failure caused by iron overload. Cirrhosis is seen in patients with hepatitis B or C. Pancreatic fibrosis may be seen in patients with insulin-dependent diabetes mellitus, and cardiac failure may occur in patients with coronary artery disease, hypertensive cardiovascular disease, or other cardiomyopathies unrelated to iron overload. All of these complications are common in the dialysis population and are not necessarily related to iron overload. In view of the common prevalence of the gene associated with primary hemochromatosis, there must be many dialysis patients who are at risk to exhibit findings of this disorder eventually. Perhaps the constant blood loss of the hemodialysis procedure prevents the development of the organ failure associated with primary hemochromatosis. Whether the administration of intravenous iron, rather than oral iron, will result in an earlier unmasking of this disorder remains to be determined. A report from Finland suggested that excess dietary and body iron was a risk factor for myocardial infarction [49]. This report has been subsequently contradicted by a large study from the United States that concludes that higher transferrin-saturation levels are not associated with an increased risk of coronary artery disease [50]. The Finnish study used only serum ferritin levels as a marker for iron status, which may be inaccurate because ferritin is also an acute phase reactant and could be falsely elevated in the presence of inflammation or infection. Cancer was more likely to develop in men, but not women, when iron stores were elevated as determined by a statistically significantly lower total iron-binding capacity and higher transferrin saturation [51]. However, serum ferritin levels were not measured. The authors assumed that there was an inverse relationship between total iron-binding capacity and serum ferritin. Although S-39 there was a statistically significant difference in the previously mentioned iron values between those men who did or did not develop cancer, the biological significance of these differences must be questioned (transferrin saturation 33.1% vs. 30.7%; total iron-binding capacity 61.4 mmol/liter vs. 62.9 mmol/liter). Increased risk of bacterial infections There is concern that iron overload promotes the proliferation of microorganisms. In vitro, free elemental iron is a growth factor for bacteria. Although free iron has been assumed to be present in iron overload states, there is no evidence to support this assumption. There is no free iron in circulation as long as transferrin is less than fully saturated. Most dialysis patients of 20 to 30 years ago who had iron overload had transferrin saturations of less than 95%, and it is rare for the parenteral irontreated patient to have a transferrin saturation chronically greater than 50%. Nevertheless, an increased incidence of infections has been reported in dialysis patients with iron overload [52–55]. This has been assumed to be due to the suppression of phagocytosis by iron as studied in vitro [56–58]. Seifert et al noted that 10 hemodialysis patients with serum ferritin levels of 1001 to 2000 ng/ml, caused by multiple RBC transfusions and not treated with desferrioxamine, had a significantly increased incidence of bacterial infections when compared with 125 “control” hemodialysis patients whose serum ferritin levels were 10 to 330 ng/ml (P , 0.01) [52]. Sixteen other hemodialysis patients treated with desferrioxamine, whose mean serum ferritin level exceeded 3000 ng/ml (range 1856 to 6112 ng/ml), also had a significantly increased incidence of bacterial infections compared with the “control” group mentioned earlier here (P , 0.01). No Yersinia infections were noted. Fourteen of these 16 patients were women over 60 years of age. The authors emphasize that the serum ferritin levels were calculated by taking the mean of several measurements throughout their study period when no active infection was present, thus avoiding spurious elevations due to infection per se. However, the inflammatory effect on serum ferritin levels may persist beyond the period of active infection, and the immunologic suppressive effects of multiple RBC transfusions could account for the increased susceptibility to infections. A second study claiming that iron overload is a risk factor for bacterial infections in dialysis patients [53] noted that the most significant factors were a previous history of infection and the presence of a “central” venous catheter. An elevated serum ferritin, particularly greater than 500 ng/ml, was also considered a risk factor for infection, but not as statistically significant (P 5 0.028) as the first two risk factors (P , 0.0001 for both prior infection and the presence of a central venous dialysis catheter); the mean 6 sd serum ferritin was 521 6 Page 165 of 290 S-40 Eschbach and Adamson: Iron overload in renal failure 775 ng/ml for those with infections (N 5 118) versus 376 6 529 ng/ml for those without infection (N 5 489). Although the differences in serum ferritin levels between the two groups may be statistically significant, it does not appear to be biologically significant in view of the large standard deviation and considerable overlap in the values between groups. These authors have recently published a prospective study on the risk factors for bacteremia in hemodialysis patients. There was no difference between the group with bacteremia and those without bacteremia as to the serum ferritin level, nor the incidence of iron therapy in the previous six months [59]. A third prospective study reported that the incidence of bacteremia was 2.92 times higher in hemodialysis patients whose serum ferritin exceeded 1000 ng/ml compared with those with lower serum ferritin levels [54]. There was no difference in the incidence of bacteremia in those with serum ferritin levels of 500 to 1000 ng/ml versus those with serum ferritin levels of less than 500 ng/ml. Serum ferritin levels also correlated significantly with the number of RBC transfusions given. Of the 98 patients studied, bacteremia was documented 29 times in 20 patients, eight of whom had ferritin levels of more than 1000 ng/ml. Fourteen patients had 17 episodes of bacteremia associated with serum ferritin levels of less than 1000 ng/ml (2 patients had bacteremia at both serum ferritin levels greater and less than 1000 ng/ml). Despite more bacteremic episodes occurring in those with serum ferritin levels less than 1000 ng/ml, the incidence/patient years of dialysis was 2.92 times greater in those with serum ferritin levels of more than 1000 ng/ml. There were no differences between the groups of patients in the types of microorganisms identified. Presumably, most, if not all, of these patients were anemic, but no data were presented. rHuEPO was given to some of the patients later in their follow-up, but no information is available about the rates of infection in these patients. A fourth study of 61 patients reported that there was a significant increase in bacterial infections and sepsis in 18 hemodialysis patients whose serum ferritin levels exceeded 500 ng/ml [55]. When 26 patients with a ferritin of less than 500 ng/ml were compared with 26 whose ferritin levels were more than 500 ng/ml, the numbers of infections were 1 versus 12, respectively (P , 0.005), and septicemias 1 versus 7, respectively (P , 0.005). However, when another group of 21 patients with iron overload was treated for aluminium intoxication with the iron chelater, desferrioxamine, the incidence of infection decreased significantly, yet the serum ferritin levels (mean 6 sem) did not decline (2493 6 219 ng/ml to 2293 6 254 ng/ml). However, when desferrioxamine therapy was stopped, the incidence of infection rose, whereas the serum ferritin levels changed little (2444 6 103 ng/ml). The authors suggested that the benefit of desferrioxamine was to bind “free” plasma iron (not bound to trans- ferrin). (A single report in dialysis patients claimed that the amount of “free” iron was greater in patients whose serum ferritin exceeded 500 ng/ml [60]. However, there was no correlation between such levels and an increased incidence of infection.) The mean transferrin saturation value was 70 6 6% prior to and 62 6 6% after approximately 16 months of desferrioxamine therapy. Whether binding of “free” iron by desferrioxamine is the reason for the decreased incidence of infections in these dialysis patients with iron overload is debatable. Because transferrin was not completely saturated, it is difficult to know whether there was “free” iron in circulation. A different study by Kessler et al concluded that bacteremia was more likely in patients with serum ferritin levels of more than 1000 ng/ml, yet this was true for only 12 of 55 patients, whereas the majority of the bacteremic (56%) and nonbacteremic (72%) patients had serum ferritin levels of less than 500 ng/ml [62]. There are a number of in vitro studies indicating that iron suppresses neutrophil function [56–58, 62]. Phagocytic function was noted to be better in 19 hemodialysis patients with serum ferritin levels more than 1000 ng/ml (13 to 950 ng/ml) than in 21 chronically transfused patients with serum ferritin levels of more than 1000 ng/ml (range 1000 to 14,370 ng/ml; median 3770 ng/ml) [56]. Phagocytosis was assumed to be dysfunctional because superoxide anion production by polymorphonuclear leukocytes (PMN) after in vitro stimulation with opsonized zymosan was less than in normal controls or those hemodialysis patients with serum ferritin levels of less than 1000 ng/ml. Although the differences were statistically significant, there was much overlap between the two groups of dialysis patients. Another study [57] noted that 91 patients with iron overload from multiple RBC transfusions (mean serum ferritin 1901 6 1044 ng/ml) had decreased PMN phagocytosis as quantitated by the amount of Yersinia enterocolitica ingested compared with 91 hemodialysis patients with a mean serum ferritin of 122 6 100 ng/ml. Although the authors attribute the increased incidence of bacterial infections in hemodialysis patients to iron overload, there are two reasons to question their conclusion: The incidence of bacterial infections in the group with iron overload was not stated, and the liver enzyme activity was greater in that group, suggesting associated hepatitis. A recent study reported that various in vitro tests of neutrophil function, particularly intracellular killing and the neutrophil oxidative burst, were more impaired in eight hemodialysis patients whose serum ferritin levels were more than 650 ng/ml (911 6 69 ng/ml, mean 6 sem) than in patients with lower serum ferritin levels [62]. This impairment in neutrophil function was similar to that observed in a group of patients with myelodysplastic syndrome who had secondary iron overload from RBC transfusions. Myelodysplastic patients are known Page 166 of 290 Eschbach and Adamson: Iron overload in renal failure to have an increased incidence of infections, whereas patients with primary hemochromatosis do not; however, the latter group also had in vitro abnormalities in neutrophil function in this study. The authors assumed the dialysis patients with neutrophil dysfunction had functional iron deficiency, however, chronic inflammation was not ruled out. The eight patients received 10 mg of iron i.v. with each dialysis, making it unlikely that they had functional iron deficiency and raising the possibility that they had an inflammatory disorder to account for the high serum ferritin and the low transferrin saturation levels. Furthermore, the clinical relevance of these findings is difficult to assess, as these patients did not have iron overload. The transferrin saturation values were low (15.6 6 3.7%, mean 6 sem), which argues against any “free” iron available to increase the likelihood of infection. Although the previously mentioned studies—most of which were conducted prior to the routine use of rHuEPO—suggest an association between iron overload and bacterial infections, factors other than iron overload may explain this association. Only 12% of patients with idiopathic hemochromatosis die with pneumonia [63], which is an incidence that is lower than the 15.5% infectious mortality in United States dialysis patients (who presumably did not have associated iron overload) for 1996 [64]. Whether the increased incidence of bacterial infections is due to iron overload or immunosuppression from established cirrhosis or diabetes mellitus in hemochromatosis is difficult to determine. Thalassemia is associated with severe iron overload from RBC transfusions. Infections appear to occur mainly in those patients having had a splenectomy [63]. Anemia (hemoglobin of less than 9.9 g/dl) is associated with a greater incidence of infection [63], and rHuEPO reverses the PMN dysfunction in dialysis patients with iron overload [65, 66]. In the latter study, the hematocrit was not stated, and the reversal in PMN dysfunction occurred after an average of six months of rHuEPO therapy, when the serum ferritin was still markedly elevated (from 1860 6 1492 ng/ml to 958 6 756 ng/ml). Consequently, it is not clear whether anemia or iron overload is the stronger determinant of PMN dysfunction. Additionally, RBC transfusions are known to be immunosuppressive [67], which could also contribute to the increased incidence of infections. Increased free radical generation There is concern that there may be increased free radical generation from free iron that will cause oxidant tissue injury. Transferrin, which is present in plasma and lymph, is normally less than 50% saturated with iron. Transferrin transports iron from the gut to the marrow and RE cells and to other tissues requiring iron. Ordinarily, there is no free iron available for the growth of S-41 microorganisms [68]. However, there remains the theoretical concern that if free iron occurs, it can be reversibly oxidized or reduced, making it potentially hazardous because of its ability to participate in the generation of powerful oxidant species, such as the hydroxyl radical, thus causing cellular injury. However, in vivo, most of the iron is bound to heme or nonheme proteins (that is, myoglobin or transferrin) and does not directly catalyze the generation of hydroxyl radicals or other oxidants [69]. An exception to this has been the observation that cisplatin-induced acute renal failure in rats may be mediated by free iron [70]. It is difficult to ascertain from the records of those dialysis patients with severe transfusioninduced iron overload whether they exhibited evidence of tissue injury from iron overload, in contrast to that related to hepatitis. In summary, iron overload in the pre-rHuEPO era was a serious problem with hepatosplenomegaly, hypersplenism, and hyperpigmentation commonly seen. 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N Engl J Med 316:73–78, 1987 39. Eschbach JW, Abdulhadi MH, Browne JK, Delano BG, Downing MR, Egrie JC, Evans RW, Friedman EA, Graber SE, Haley NR, Korbet S, Krantz SB, Lundin AP, Nissenson AR, Odgen DA, Paganini EP, Rader B, Rutsky EA, Stivelman J, Stone WJ, Teschan P, Van Stone JC, Van Wyck DB, Zuckerman K, Adamson J: Recombinant human erythropoietin in anemic patients with end-stage renal disease: Results of a phase III multicenter clinical trial. Ann Intern Med 111:992–1000, 1989 40. Sunder-Plassmann G, Hörl WH: Importance of iron supply for erythropoietin therapy. Nephrol Dial Transplant 10:2070–2076, 1995 41. Eschbach JW, Haley NR, Egrie JC, Adamson JW: A comparison of the responses to recombinant human erythropoietin in normal and uremic subjects. Kidney Int 42:407–416, 1992 42. Eschbach JW, Haley NR, Aquiling T, Browne JK, Downing MR, Egrie JC, Adamson JW: Three years of erythropoietin (rHuEPO) therapy. (abstract) Kidney Int 37:237, 1990 43. United States Renal Data System. The USRDS Dialysis Morbidity and Mortality Study (wave 1), in U.S. Renal Data System 1996 Annual Data Report 4, Bethesda, National Institutes of Health, National Institute Diabetes and Digestive and Kidney Diseases, 1996, pp 45–67 44. Deleted in proof. 45. Bregman H, Gelfand MC, Manz HJ, Winchester JF, Knepshield JH, Schreiner GE: Iron-overload-associated myopathy in patients on maintenance haemodialysis: A histocompatibility-linked disorder. Lancet 2:882–885, 1980 46. Edwards CQ, Griffen LM, Kaplan J, Kushner JP: Twenty-four hour variation of transferrin saturation in treated and untreated haemochromatosis homozygotes. J Intern Med 226:373–379, 1989 47. Taccone-Gallucci M, Di Nucci GD, Meloni C, Valeria M, Adorno D, Elli M, Mariani G, Mandelli F, Casciani CU: Transfused and pharmacological iron: Relationship of overload to HLA antigens. Proc Eur Dial Transplant Assoc 20:150–155, 1983 48. Maher ER, Curtis JR: Serum ferritin in haemodialysis patients: Is there a relationship to ‘haemochromatosisis alleles’ HLA A3, B7 B14? Nephron 43:43–44, 1986 49. Salonen JT, Nyyssonen K, Korpela H, Tuomilehto J, Seppanen R, Salonen R: High stores iron levels are associated with excess risk of myocardial infarction in eastern Finnish men. Circulation 86:803–811, 1992 50. Sempos CT, Looker AC, Gillum RF, Makuc DM: Body iron stores and the risk of coronary heart disease. N Engl J Med 330:1119–1124, 1994 51. Stevens SG, Jones DY, Micozzi MS, Taylor PR: Body iron stores and the risk of cancer. N Engl J Med 319:1047–1052, 1988 Page 168 of 290 Eschbach and Adamson: Iron overload in renal failure 52. Seifert A, Von Herrath D, Schaefer K: Iron overload, but not treatment with desferrioxamine favours the development of septicemia in patients on maintenance hemodialysis. Q J Med 65:1015– 1024, 1987 53. Hoen B, Kessler M, Hestin D, Mayeux D: Risk factors for bacterial infections in chronic haemodialysis adult patients: A multicentre prospective survey. Nephrol Dial Transplant 10:377–381, 1995 54. Boelaert JR, Daneels RF, Schurgers ML, Matthys EG, Gordts BZ, Van Landuyt HW: Iron overload in haemodialysis patients increases the risk of bacteraemia: A prospective study. Nephrol Dial Transplant 5:130–134, 1990 55. Tielelmans CL, Lenslud CM, Wens R, Collart FE, Dratwa M: Critical role of iron overload in the increased susceptibility of haemodialysis patients to bacterial infections: Beneficial effects of desferrioxamine. Nephrol Dial Transplant 4:883–887, 1989 56. Flament J, Goldman M, Waterlot Y, Dupont E, Wybran J, Vanhenweghem J-L: Impairment of phagocyte oxidative metabolism in hemodialyzed patients with iron overload. Clin Nephrol 25:227–230, 1986 57. Cantinieaux BF, Boelaert J, Hariga CF, Fondu P: Impaired neutrophil defense against Yersinia enterocolitica in patients with iron overload who are undergoing dialysis. J Clin Lab Med 111:524– 528, 1988 58. Vanholder R, Van Bieson W, Ringoir S: Contributing factors to the inhibition of phagocytosis in hemodialyzed patients. Kidney Int 44:208–214, 1993 59. Hoen B, Paul-Dauphin A, Hestin D, Kessler M: EPIBACDIAL: A multicenter prospective study of risk factors for bacteremia in chronic hemodialysis patients. Am J Nephrol 9:869–876, 1998 60. Tielemans C, Andre M, Willems D: Plasma non-transferrin 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. S-43 bound iron in haemodialysis patients. (abstract) Nephrol Dial Transplant 3:544–545, 1988 Kessler M, Hoen B, Mayeux D, Hestin D, Fontenaille C: Bacteremia in patients on chronic hemodialysis. Nephron 64:95–100, 1993 Patruta SI, Edlinger R, Sunder-Plassmann G, Hörl WH: Neutrophil impairment associated with iron therapy in hemodialysis patients with functional iron deficiency. J Am Soc Nephrol 9:655– 663, 1998 Hershko C, Peto TEA, Weatherall DJ: Iron and Infection. BMJ 296:660–664, 1988 United States Renal Data System 1997: Annual data report. VI. Causes of death. Am J Kidney Dis 30(Suppl 1):S107–S117, 1997 Boelaert JR, Cantinieaus BF, Hariga CF, Fondu PG: Recombinant erythropoietin reverses polymorphonuclear granulocyte dysfunction in iron-overload dialysis patients. Nephrol Dial Transplant 5:504–507, 1990 Veys N, Vanholder R, Ringoir S: Correction of deficient phagocytosis during erythropoietin (EPO) threatment in maintenance hemodialysis patients. Am J Kidney Dis 19:358–363, 1992 Klein HG: Immunologic aspects of blood transfusion. Semin Oncol 21:16–20, 1994 Ward CG: Iron and infection: New developments and their implications. J Trauma 41:356–364, 1996 Halliwell B, Gutteridge JMC: Role of free radicals and catalytic metal ions in human disease: An overview. Methods Enzymol 186:1–85, 1990 Biliga R, Zhang Z, Baliga M, Ueda N, Shah S: In vitro and in vivo evidence suggesting a role for iron in cisplatin-induced nephrotoxicity. Kidney Int 53:394–401, 1998 Page 169 of 290 2111 CHAPTER 24 Sensitization 2001 Steven Hardy, SUQHui Lee, and Paul 8. Terasaki Terasaki Foundation Laboratory, Los Angeles, California The three sources of sensitization as shown by For the trend study, patients registered in the UNOS development of HLA antibodies are: rejection of a graft, Kidney Transplant Registry from 1991-2000 were uti- transfusion, and pregnancy. We re-examine here the lized for analysis . For the remainder of the studies, effect of these three factors on the outcome of recent patients transplanted from 1995 through 2000 were transplants after the introduction of new immunosup- analyzed . Graft survival was calculated according to pression (1995-2000). During this same time period, Kaplan and Meir. Unless otherwise stated, the graft the more sensitive flow cytometry crossmatching tests survival was for first transplant patients. became more widespread. As a result, sensitization , per se, has come to have a relatively smaller effect. The transfusion effect was also re-examined . RESULTS The following fjgures summarize the results of these analyses . Figure 1. Yearly trend in transfusions. The numbers of transfusions given to kidney trans- tients continue to be transfused. Today it is unlikely that plant patients has decreased from a peak of 64% in patients are being transfused deliberately to obtain 1992 being transfused down to 36% in 2000 . Even after the introduction of Epogen, over one-third of pa- higher graft survival. Clinical Transplants 2001 , Cecka and Terasaki, Eds. UCLA Immunogenetics Center, Los Angeles, California Page 170 of 290 272 HARDY, LEE, AND TERASAKI Figure 2. Transfusions in patients with various diseases. Patients with polycystic kidney disease received the least number of transfusions and SLE patients received the most. In all diseases, females received more transfusions than males. Figure 3. Sensitization and transfusions in first transplant patients. tized. This incidence may represent errors in false positive PRA results, possibly due to autoantibodies or in reporting transfusions, since males without transfusions should not have HLA antibodies. Non-transfused, in sensitization . With more transfusions, the incidence of sensitization increased for all groups. Tis increase was greater in females than in males and in parous females compared with non-parous females. It should also be noted that these rates of sensitization do not nulliparous females likewise should not have HLA an- reflect the true sensitization rate of any of these factors tibodies, but 20% were classified as sensitized. Among females, an additional source of sensitization could be unrecognized or unreported pregnancies. Pregnancies without transfusions resulted in only a minor increase since they represent the rates present in patients who were transplanted. Many more patients could have been sensitized, but not transplanted. Among non-transfused males, 13% were sensi- Page 171 of 290 273 Figure 4. Sensitization after transfusions in regraft patients. When regraft patients were examined, the rate of the fact that these patients had rejected a prior trans- sensitization was considerably greater than for first graft plant. Thus rejection of a graft is a greater stimulus for patients as shown in Figure 3. Also, the effect of in- production of HLA antibodies than transfusions or preg- creasing numbers of transfusions was not as great as nancies. Figure 5. Sensitization of males and females with various diseases. In these diseases, some correlation of sensitiza- where transfusions are more frequently performed tend tion with the frequency with which patients with these to have more sensitization . Females again were more diseases are transfused can be noted by comparing sensitized than males. the results to Figure 2. That is, patients with diseases Page 172 of 290 214 HARDY, LEE, AND TERASAKI o Male N 21 ,826 II!l Nulliparous 3,797 Parous 7,742 Figure 6. Effect ofpregnancies on graft survival. Males, nulliparous females and parous females who were non-sensitized all had approximately the lower graft survival, with the parous females having the lowest survival. same graft survival. When sensitized, they had a slightly Figure 7. Effect of transfi.tsion on graft survival. Among non-sensitized and sensitized patients, those with no transfusions had the highest graft survival and those with the greatest number of transfusions had the lowest graft survival. This is opposite to the earlier "transfusion effect" in which patients with no transfusions had the lowest survival. This complete turnaround in the data appears to have occurred in the past 5 years. Page 173 of 290 275 For cadaver donor reg raft patients in non-sensitized patients, had a 3 year graft survival rate which was only 3% below that for first transplants. The difference in survival occurs in the first 6 months after transplantation, suggesting that undetected antibodies may have resulted in early loss of reg raft patients without antibodies. Also it should be noted that PRA tests were performed mostly by cytotoxocity. Among patients who were sensitized (PRA>10%), the 3 year graft survival difference was 4% between first and reg raft patients. Again the difference developed within the first 6 months after transplantation. Sensitized and non-sensitized patients had almost the same graft survival in living donor transplants. Adult Diab %PRA %PRA N • 0-10 11-50 • 0-10 6,002 11-50 894 377 --------------------%PRA N .0-10 2,952 011-50 474 A >50 250 %PRA %PRA • 0-10 o 11-50 • 0-10 2,056 o 11-50 342 203 N of sensitization on graft survival ofpatients with various diseases. In general, for the diseases shown, graft survival >50%, had a lower graft survival. A statistically signifi- for unsensitized patients and sensitized patients with cant lower graft survival was seen for patients with SLE PRA <50% were the same. Only patients with PRA ( p<0.001) and adult diabetes (p<0.01). Page 174 of 290 276 HARDY, LEE, AND TERASAKI Figure 10. Effect of HLA matching in primary graft and regraft patients of various diseases. The HLA-AB mismatching effect was the same for HLA-DR mismatches had a greater effect in reg rafts first and reg raft patients since the difference between since the difference between 0 and 2 DR mismatches the best and worst matches was 6% for first grafts and was 5% for first grafts and 10% for regrafts. 6% for regrafts. HLA-ABDR mismatches had a difference between best and worst matches of 7% for first graft and 9% for regrafts. Page 175 of 290 277 ABDRMM N 2,807 5,961 8,164 2,860 ABDRMM o 0 1-2 3-4 5-6 ~=.."...,.,.,.,.,.."..,.., Figure 11. Effect of HLA matching on first and regrafl patients in living donor transplants. The most striking effect is the superiority of transplants with 0 AS, 0 DR, and 0 ASDR mismatch in first and regraft patients. These probably represent HLA identical sibling donor grafts, that provide essentially the same graft survival in first and regraft patients. Page 176 of 290 278 HARDY, LEE, AND TERASAKI DISCUSSION period of a decade since the first discovery of the trans- Rejection of a kidney was the most powerful means by which patients became sensitized . Transfusions were next in ability to sensitize, followed by pregnancies. In all these instances, females were more prone to become sensitized than males, possibly because of more unreported transfusions or pregnancies . The greater need for transfusions among females was noted for those with all the various diseases. The so-called "transfusion effect" was found to have completely reversed itself in the recent data. The paradoxical effect of transfusions producing a higher graft survival was no longer found. Instead, both in sensitized and non-sensitized patients, patients with no transfusions had the highest graft survival and those with the most transfusions had the lowest survival. For over a 1. The rate of transfusion decreased from 64% in 1992 to 36% in 2000. This need for transfusions fusion effect (1) to its disappearance (2), we did not understand its origin . The situation as we now see it can be explained on the simple basis of sensitization by transfusion. Sensitization, as measured by development of HLA antibodies is shown here to have become a relatively small factor influencing the outcome of transplants. Its largest effect is in reg raft patients, where HLA-oR mismatching was again shown to be the most important factor (3). survival than non-sensitized patients. As in the prior experience, the most effective way of handling sensitization was the use of kidneys from HLA-matched related donors. 5. continued despite the introduction of erythropoetin. Females were transfused more frequently than males. SLE patients were transfused more often than those with other diseases. 2. Transfusions no longer had a beneficial effect on the outcome of transplantation, but rather with 6. Rejection of a kidney transplant had the strongest effect on sensitization, followed by transfu- 7. sion and then pregnancies. Females were more susceptible to sensitization than males. Al- For cadaver donor reg raft patients, HLA-oR mismatch had a greater effect than AB mismatch. graft survival in cadaver donor reg raft patients mismatched for 2 OR antigens than mismatched been sensitized, as many as 13% were reported to have antibodies. As many as 20% of nullipa- 4. Patients with polycystic kidney disease had the There was a 10 percentage point lower 3-year though non-transfused males should not have rous females without transfusions also were reported to have antibodies. SLE patients were most often sensitized among diseases were more sensitized than males. Unsensitized reg raft patients had a 3% lower 3-year graft survival than unsensitized first graft patients. Among sensitized patients, regraft patients had a 4% lower graft survival than sensitized first graft patients. highest 3-year graft survival in both the sensitized and non-sensitized patients. Sensitization to a PRA level of less than 50% was not detrimental to patients with all the various diseases. more transfusions, the graft outcome became lower, as might be expected. 3. SLE and adult diabetic patients with PRA >50% were also shown have significantly lower graft for 0 OR antigens. 8. For living donor transplants, regrafts from 0 AB or o OR mismatched transplants had the same graft survival as first transPlants)' patients with various diseases. Females of all REFERENCES 1. Opelz G, Sengar DPS, Mickey MR, Terasaki PI. Effect of blood transfusion on subsequent kidney transplant. Transplant Proc 1973;4:253-259. 2. Opelz G for the Collaborative Transplant Study: Effect of HLA matching in 10,000 cyclosporine-treated cadaver kidney transplants. Transplant Proc 1987; 19:641 -646. 3. Cecka JM, Terasaki PI. Repeating HLA antigen mismatches in renal transplants - A second class mistake? Transplantation 1994; 57:515-519. Page 177 of 290 Blood Transfusions in Kidney Transplant Candidates Are Common and Associated With Adverse Outcomes Hassan N. Ibrahim, MD, MS,1 Melissa A. Skeans, MS,2 Qi Li, MS,2 Areef Ishani, MD, MS,1,2 Jon J. Snyder, PhD, MS2 1 Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA 2 Chronic Disease Research Group, Minneapolis Medical Research Foundation, Minneapolis, Minnesota, USA Running head: Transfusions Before Kidney Transplant Corresponding Author Hassan N. Ibrahim, MD, MS Division of Renal Diseases and Hypertension, University of Minnesota 717 Delaware Street SE, Suite 353 Mail Code 1932 Minneapolis, MN 55414 USA Phone, 612-624-9444; fax, 612-626-3840; [email protected] 1 Page 178 of 290 Ibrahim HI, Skeans MA, Li Q, Ishani A, Snyder JJ. Blood Transfusions in Kidney Transplant Candidates Are Common and Associated With Adverse Outcomes. Clin Transplant. Abstract Surprisingly, there are no data regarding transfusion frequency, factors associated with transfusion administration in patients on the kidney transplant waiting list, or transfusion impact on graft and recipient outcomes. We used United States Renal Data System data to identify 43,025 patients added to the waiting list in 1999-2004 and followed through 2006 to assess the relative risk of post-listing transfusions. In 69,991 patients who underwent transplants during the same time period, we assessed the association between pretransplant transfusions and level of panel-reactive antibody (PRA) at the time of transplant, and associations between PRA and patient outcomes. The 3-year cumulative incidence of transfusions was 26% for patients added to the waiting list in 1999, rising to 30% in 2004. Post-listing transfusions were associated with a 28% decreased likelihood of undergoing transplant, and a more than 4-fold increased risk of death. There was a graded association between percent PRA at the time of transplant and adjusted risk of death-censored graft failure, death with function, and the combined event of graft failure and death. These data demonstrate that transfusions remain common, and confirm the adverse association between transfusions and PRA, and high PRA and inferior graft and patient outcomes. Keywords: Blood transfusion, kidney transplantation, graft survival, waiting list, panel-reactive antibody Corresponding Author: Hassan N. Ibrahim, MD, MS, Division of Renal Diseases and Hypertension, University of Minnesota, 717 Delaware Street SE, Suite 353, Mail Code 1932, Minneapolis, MN 55414 USA [email protected] 2 Page 179 of 290 Introduction The kidney transplant waiting list continues to grow, and candidates with high levels of panel-reactive antibody (PRA) experience an increasingly prolonged waiting time and incur increased risk of graft failure when they undergo transplant (1-6). This is of major relevance as 39.6% of currently listed transplant candidates have PRA > 10%, 15.8% have PRA > 20%, and 5.1% have PRA > 80% (7). We recently demonstrated surprisingly high frequency of blood transfusion administration, a major cause of sensitization, in dialysis patients and also in nondialysis-dependent chronic kidney disease (CKD) patients (8;9). Interestingly, despite the common and firmly held belief that the relationship between blood transfusions, sensitization, and adverse outcomes is well established, we found no detailed accounts of how often transfusions are administered to waitlisted patients. Furthermore, there is no information regarding the impact of transfusions on kidney transplant outcomes in recent years. Therefore, we determined the frequency of and factors associated with postlisting blood transfusions, and the effect of these transfusions on the likelihood of death or undergoing transplant while on the list and elevated PRA level at the time of transplant. We also assessed the association of elevated PRA level at the time of transplant with the adjusted risk of adverse patient and graft outcomes. We hypothesized that transfusions occur much more frequently in this population than is currently appreciated by the transplant community, and that these transfusions are not inconsequential. Materials and Methods We conducted a retrospective cohort study using the United States Renal Data System (USRDS) standard analytic files, which contain all Organ Procurement and Transplantation 3 Page 180 of 290 Network (OPTN) data related to kidney transplants, including the kidney transplant waiting list and OPTN form data, which include transplant candidate registration data (candidate demographic and clinical characteristics recorded at the time of wait listing), transplant recipient registration data for patients who undergo transplants, and recipient histocompatibility data (PRA information). The USRDS standard analytical files contain all Centers for Medicare & Medicaid Services (CMS) end-stage renal disease (ESRD) data, including data from the Medical Evidence Report (form CMS-2728), the Medicare enrollment database (coverage periods and patient demographics), the ESRD Death Notification (form CMS-2746), Medicare Part A institutional claims (inpatient, outpatient, skilled nursing facility, home health, and hospice), and Medicare Part B physician (inpatient and outpatient) and supplier claims (used to identify blood transfusions). Study Population The study population consisted of 43,025 Medicare patients added to the kidney transplant waiting list in 1999-2004. Patients listed for combined organ transplants (kidneypancreas, kidney-liver, kidney-lung, kidney-heart, or any other combination), patients with prior kidney transplants, and patients who were ESRD certified after listing were excluded. Assessment of trends in transfusion use was limited to patients with Medicare primary coverage because claims for transfusions are available for them but not for patients without Medicare coverage. To assess the trends in most recent and peak PRA at the time of transplant and the impact of PRA on graft and patient outcomes, we studied 69,991 transplant recipients who underwent transplants during the same time period, 1999-2004 with follow-up through 2006. Blood transfusion use was assessed after listing for patients with Medicare primary coverage. Blood transfusions were identified in inpatient, outpatient, skilled nursing, and 4 Page 181 of 290 physician/supplier Medicare claims using Current Procedural Terminology and International Classification of Diseases, Ninth Edition, Clinical Modification procedure codes. For patients undergoing transplant, OPTN collects current and peak PRA data and supplies them to the USRDS. More than 90% of PRA values are complete for transplant patients. Analysis The cumulative incidence of postlisting transfusions through 3 years after listing was assessed using the Kaplan-Meier method as 1 minus the Kaplan-Meier estimate and presented as a percentage. Adjusted hazard ratios for postlisting transfusions were estimated using a Cox proportional hazards model. The association between the first postlisting transfusion and the subsequent likelihood of transplant and risk of death were estimated using an adjusted timedependent Cox proportional hazards model with the time to first transfusion entered as a timedependent covariate. The adjusted odds ratios of having PRA ≥ 10%, 20%, and 80% at the time of transplant by prior transfusion status were estimated using logistic regression for patients who underwent transplants during 1999-2004. A Cox proportional hazards model was then used to compute the adjusted hazard ratios for death-censored graft failure, death with function, or the combined outcome by PRA at the time of transplant. Adjustments were made for sex, prior pregnancy, age, race, ethnicity, pretransplant dialysis duration, dialysis modality, primary cause of ESRD, transplant year, body mass index (BMI), recipient and donor hepatitis C and cytomegalovirus status, number of HLA matches, primary insurance, and presence of congestive heart failure, ischemic heart disease, cerebrovascular accidents, peripheral vascular disease, cancer, and tobacco use. Adjustments were also made for the following donor factors: donor type, cold ischemia time, age, sex, BMI, race, and history of diabetes. Adjusted hazard ratios 5 Page 182 of 290 were calculated for a PRA of 1%-19%, 20%-79%, and ≥ 80%, all in comparison to a PRA of 0% at the time of transplant. All analyses were conducted using SAS version 9.1.3 (SAS Institute, Cary, NC). Results In total, 43,025 US Medicare patients were added to the waiting list in 1999-2004 (Table 1). Men, whites, and patients with diabetic nephropathy accounted for most listings. Regarding comorbid conditions, 11% had atherosclerotic heart disease, 15% had congestive heart failure, and 3.6% had a history of cerebrovascular accidents. In 1999, 26% received one or more transfusions in the first 3 years after listing; that proportion was 30% in 2004. Patients with a higher likelihood of transfusions while on the list were older, female, and white, with diabetes as cause of ESRD, lower BMI, and longer dialysis duration before wait listing (Table 1). Interestingly, peritoneal dialysis patients were more likely to receive transfusions (31% versus 28% for hemodialysis patients, P < 0.0001). As one may expect, candidates with comorbid conditions were more likely to receive transfusions. The 1-year cumulative incidence of transfusions while on the waiting list for all patients added to the list between 1999 and 2004 was 10.8%; 3-year cumulative incidence was 27.7%. Cumulative incidence of transfusions was highest for patients aged > 65 years (Figure 1). Erythropoiesis stimulating agent (ESA) use was not entered into the primary model assessing predictors of transfusions, as 80% of waitlisted patients were receiving ESAs. When ESA use was entered into the model, however, it was associated with a 2-fold increase in the risk of receiving a transfusion (hazard ratio [HR] 2.06, 95% confidence interval [CI] 1.86-2.29). Including ESA use in the regression model predicting transfusions did not change the magnitude of the associations of other variables with transfusion risk (data not shown). 6 Page 183 of 290 In a model adjusting for year of listing, age, sex, race, ethnicity, primary cause of ESRD, blood type, education, BMI, prelisting dialysis duration, dialysis modality, and comorbid conditions, receiving a blood transfusion while on the list was associated with a more than 4-fold increase in risk of death (HR 4.04, 95% CI 3.78-4.31), and a 28% lower likelihood of undergoing transplant (Figure 2). Receiving any pretransplant transfusion was associated with higher odds of PRA ≥ 10%, 20%, and 80% at the time of transplant (Figure 3). This risk was highest for multiparous women. PRA at the time of transplant was associated with a step-wise graded association with death-censored graft failure, death with function, and the combined outcome (Figure 4). Patients with PRA of 20% to 79% were 21% more likely (95% CI 1.12-1.32) to experience deathcensored graft failure, 15% more likely (95% CI 1.05-1.26) to experience death with function, and 18% more likely (95% CI 1.11-1.26) to experience the combined outcome. For highly sensitized patients (PRA ≥ 80%), the adjusted hazard ratios for these events were 1.41 (95% CI 1.22-1.62), 1.19 (95% CI 1.00-1.41), and 1.30 (95% CI 1.17-1.45), respectively. We also provide the parallel hazard ratios for the subsets of patients with without transfusion history (Table 2). We did not include transfusion history as a main effect in the models, as it is on the causal pathway for PRA elevation. In prior modeling, we found no significant interaction between transfusion history and PRA category for any of the outcomes. Discussion These results demonstrate that a significant proportion of waitlisted kidney transplant candidates receive blood transfusions after being listed. The transfusions were not inconsequential, as they were associated with sensitization, excess death, and a significantly 7 Page 184 of 290 lower likelihood of undergoing kidney transplant. These data also strengthen the link between higher PRA and poor graft outcomes, in a regression model that adjusted for many important donor and recipient factors. A third of patients received transfusions in the first 3 years after being listed; these data are very surprising in an era with effective strategies to treat anemia of CKD, heightened awareness against transfusions, and declining ability to administer transfusions in dialysis units. Prior studies have shown that introduction of epoetin has resulted in a significant decrease in blood transfusion incidence among listed candidates, and that ESA use is associated with markedly reduced sensitization and waiting time (10). Many of these transfusions are likely given due to acute events such as gastrointestinal bleeding or surgery, and could not be prevented by anemia treatment. Some transfusions may also reflect a general feeling in the medical community that patients with cardiovascular disease need higher hemoglobin levels, despite lack of evidence to support such practice (11). While the reason for transfusions was not included in the Medicare claims data, the recent observation by Lawler et al, using data from the Veterans Administration Health Care System, supports the suggestion that CKD patients with anemia receive transfusions more often than other patients (12). In this analysis and even after excluding transfusions that occurred as a result of an acute bleeding event, diagnosis of pernicious or hemolytic anemia, or surgery within the month preceding the index hemoglobin value that triggered the transfusion, CKD patients, particularly those not receiving ESAs or iron, received transfusions at an alarming frequency of 22% to 58% depending on the hemoglobin level (12). As there is little doubt that patients with multiple comorbid conditions, who would have been excluded from undergoing transplants in the past, now undergo transplants, these high rates of transfusions may not be entirely surprising. The 8 Page 185 of 290 adjustments made in our model attempt to address this issue, but likely cannot address it completely. Some blood transfusions given to waitlisted patients may have been given intentionally to improve graft survival, as has been previously described (13-16). However, the practice of giving transfusions to potential kidney transplant patients, from their directed donors or from random donors, has fallen out of favor more recently, as the introduction of modern immunosuppressants, particularly calcineurin inhibitors, has dramatically reduced the incidence of acute rejection, and showing benefit of such a practice became difficult. In fact, a recent analysis of the relationship between pretransplant blood transfusions and transplant outcomes did not demonstrate any benefit (16). Therefore, this possibility is unlikely to have contributed to the surprisingly high prevalence of transfusions that we observed. It is worth mentioning that prelisting transfusions are also common. In fact, over 40% of kidney transplant candidates received transfusions before being waitlisted before 2001. While they were not the main focus of the current analysis, we studied prelisting transfusions in the cohort of patients added to the waiting list in 1995-2001, the timeframe in which the question regarding “any previous transfusions” was included on the OPTN Transplant Candidate Registration form, and answers were collected and routinely reported for new transplant candidates. We found that 41% of patients reported prelisting transfusions in 2001. Within 1 year of wait-listing, 30.5% of patients who received prelisting transfusions received kidney transplants, compared with 32.2% of patients who did not receive prelisting transfusions (P < 0.001). Prelisting transfusions were associated with a higher likelihood of receiving transfusions while on the list and a higher risk of death and lower likelihood of undergoing transplant (data not shown). 9 Page 186 of 290 This analysis has limitations. The demonstrated effect of high PRA on graft outcomes may be related to development of donor-specific antibodies, which are clearly linked to antibody-mediated rejection (6,17-19). Our data source does not allow us to distinguish between high-PRA recipients with and without donor-specific antibodies. Moreover, we did not address results of cross-match at the time of transplant. Most recently, flow cytometry-based PRA assays have almost become the standard; whether the association observed with cytotoxic PRA and outcomes is similar is yet to be seen, but trends are likely to be the same. Identifying blood transfusions using Medicare claims required that we limit the population studied to the Medicare-primary-payer population, which makes up only 50% of incident wait listings in any given year. Medicare-based data also lack important laboratory values, such as hemoglobin levels at which transfusions took place. This is an analysis of primary kidney transplant patients only, who currently account for 83% of all transplant patients. Patients listed for combined kidneypancreas transplants were excluded, possibly reducing the number of diabetic patients studied; diabetic patients have a high comorbidity burden and not uncommonly receive transfusions. The adverse impact of postlisting transfusions on patient and graft outcomes may be at odds with the recent analysis by Scornik et al (20). These investigators found that 45% of their 746 kidney transplant patients received transfusions mainly in the first month after transplant. Interestingly, the incidence of posttransplant antibodies was similar for patients who received transfusions and for those who did not, and only one-twelfth of patients who received ≥ 10 units became sensitized. The incidence of rejection and allograft loss were numerically but not statistically higher for patients who received transfusions. Conceivably, receiving transfusions while heavily immunosuppressed may not be as deleterious. One must seriously consider that 10 Page 187 of 290 these surprisingly high rates of transfusions may become more common, as ESA use is not without risks and may harm some patients. While the transplant community proactively avoids transfusions in potential transplant candidates, transfusions are clearly common, and this issue needs further study. An additional challenge involves choosing whether to treat anemic CKD patients, particularly those with type 2 diabetes mellitus, with transfusion or ESA, as ESA use may increase risk of stroke in this population. This issue is very relevant because type 2 diabetes is a major reason patients are referred for transplants (21). In summary, these data reveal a surprisingly high frequency of blood transfusions among ESRD patients on the kidney transplant waiting list. These transfusions appear to be associated with higher risk of death, lower likelihood of undergoing transplant, and sensitization with its attendant inferior long-term graft survival. More studies are needed to understand the reasons for these transfusions, and efforts directed at minimizing their frequency should be carefully balanced against the potential adverse consequences of ESA use, particularly in CKD patients with type 2 diabetes. Acknowledgments This study uses data supplied by the United States Renal Data System. The interpretation and reporting of these data are the responsibility of the authors and in no way should be seen as an official policy or interpretation of the US government. The authors would like to thank Chronic Research Group colleagues Shane Nygaard, BA, for manuscript preparation, and Nan Booth, MSW, MPH, ELS, for manuscript editing. This study was supported by a research contract from Amgen Inc., Thousand Oaks, California. The contract provides for the authors to 11 Page 188 of 290 have final determination of the content of this manuscript. Hassan N. Ibrahim and Areef Ishani consult for, and Melissa A. Skeans, Qi Li, and Jon J. Snyder are employed by, the Chronic Disease Research Group. Author Contributions Hassan N. Ibrahim, research design, data analysis, preparation of manuscript; Melissa A. Skeans, data analysis, preparation of manuscript; Qi Li, data analysis, preparation of manuscript; Areef Ishani; research design, data analysis, preparation of manuscript; Jon J. Snyder, research design, data analysis, preparation of manuscript. 12 Page 189 of 290 Reference List [1] Andreoni KA, Brayman KL, Guidinger MK, Sommers CM, Sung RS. Kidney and pancreas transplantation in the United States, 1996-2005. Am J Transplant 2007;7:13591375. [2] The Scientific Registry of Transplant Recipients: 2007 OPTN/SRTR Annual Report: Transplant Data 1997-2006. Table 5.2: Time to transplant. Available at: www.ustransplant.org. Accessed October 4, 2010. [3] Cardarelli F, Pascual M, Tolkoff-Rubin N, et al. Prevalence and significance of anti-HLA and donor-specific antibodies long-term after renal transplantation. Transpl Int 2005;18:532-540. [4] Sautner T, Gnant M, Banhegyi C, et al. Risk factors for development of panel reactive antibodies and their impact on kidney transplantation outcome. Transpl Int 1992;5 Suppl 1:S116-S120. [5] Terasaki PI, Ozawa M. Predicting kidney graft failure by HLA antibodies: a prospective trial. Am J Transplant 2004;4:438-443. [6] Opelz G, Dohler B. Effect of human leukocyte antigen compatibility on kidney graft survival: comparative analysis of two decades. Transplantation 2007;84:137-143. [7] US Renal Data System, USRDS 2004 Annual Data Report: Atlas of End-Stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 2004. 13 Page 190 of 290 [8] Ibrahim HN, Ishani A, Foley RN, Guo H, Liu J, Collins AJ. Temporal trends in red blood transfusion among US dialysis patients, 1992-2005. Am J Kidney Dis 2008;52:11151121. [9] Ibrahim HN, Ishani A, Guo H, Gilbertson DT. Blood transfusion use in non-dialysisdependent chronic kidney disease patients aged 65 years and older. Nephrol Dial Transplant 2009;24:3138-3143. [10] Vella JP, O'Neill D, Atkins N, Donohoe J, Walshe J. Sensitization to human leukocyte antigen before and after the introduction of erythropoietin. Nephrol Dial Transplant 1998;13:2027-2032 [11] Besarab A, Bolton WK, Browne JK, et al. The effects of normal as compared with low hematocrit values in patients with cardiac disease who are receiving hemodialysis and epoetin. N Engl J Med 1998;339:584-590. [12] Lawler E, Bradbury B, Fonda JR, Gaziano J, Gagnon D. Transfusion burden among patients with chronic kidney disease and anemia. Clin J Am Soc Nephrol 2010;5:667672. [13] Salvatierra O, McVicar J, Melzer J, et al. Improved results with combined donor-specific transfusion (DST) and sequential therapy protocol. Transplant Proc 1991;23:1024-1026. [14] Lockard-Marduel A, Gumbert M, Tomlanovich S, Amend W, Vincenti F, Schralla P, Melzer J, Feduska NJ, Salvatierra O, Jr., Garovoy MR: Immunologic alterations induced by donor-specific transfusion. Transplant Proc 1989;21:1171-1172. [15] Salvatierra O, Jr., Melzer J, Vincenti F, et al. Donor-specific blood transfusions versus cyclosporine--the DST story. Transplant Proc 1987;19:160-166. 14 Page 191 of 290 [16] Aalten J, Bemelman FJ, van den Berg-Loonen EM, et al. Pre-kidney-transplant blood transfusions do not improve transplantation outcome: a Dutch national study. Nephrol Dial Transplant 2009;24:2559-2566. [17] Glotz D, Antoine C, Duboust A. Antidonor antibodies and transplantation: how to deal with them before and after transplantation. Transplantation 2005;79(Suppl 3):S30-S32. [18] Vasilescu ER, Ho EK, Colovai AI, et al. Alloantibodies and the outcome of cadaver kidney allografts. Hum Immunol 2006;67:597-604. [19] Gebel HM, Bray RA, Nickerson P. Pre-transplant assessment of donor-reactive, HLAspecific antibodies in renal transplantation: contraindication vs. risk. Am J Transplant 2003;3:1488-1500. [20] Scornik J, Schold J, Bucci M, Meier-Kriesche U. Effects of blood transfusions given after renal transplantation. Transplantation 2009;87:1381-1386. [21] Pfeffer M, et al. A trial of darbepoetin alfa in type 2 diabetes and chronic kidney disease. New Engl. J Med 2009;361:2019. 15 Page 192 of 290 Table 1. Factors Associated With Post-Listing Transfusions Factor Year of listing 1999 2000 2001 2002 2003 2004 Age at listing, yr 18-34 35-49 50-64 ≥ 65 Sex Men Women Race White African American Native American Asian Other Primary cause of ESRD Diabetes Hypertension GN Cystic Other Unknown BMI, at listing kg/m2 < 18.5 18.5-24.9 25-29.9 30-34.9 ≥ 35 Unknown Pre-listing dialysis duration, yr <1 1-< 2 2- < 3 ≥3 % of population 3-year Cumulative Adjusted hazard * (n = 43,025) Transfusion Incidence, % ratio (95% CI) P 13.9 15.4 15.7 17.0 18.3 19.7 26 27 28 29 28 30 1.00 reference 1.07 (0.99-1.15) 1.04 (0.96-1.12) 0.98 (0.91-1.06) 0.89 (0.82-0.97) 1.02 (0.94-1.10) 15.1 29.4 38.4 17.1 24 25 30 33 1.00 reference 1.02 (0.95-1.09) 0.6695 1.14 (1.06-1.22) 0.0004 1.25 (1.15-1.36) < 0.0001 59.5 40.5 26 31 1.00 reference 1.25 (1.20-1.31) < 0.0001 55.2 36.6 1.7 5.2 1.3 30 26 27 24 25 1.00 reference 0.87 (0.82-0.91) < 0.0001 0.78 (0.67-0.92) 0.0027 0.75 (0.68-0.83) < 0.0001 0.97 (0.82-1.15) 0.7218 35.8 25.7 18.0 4.6 2.5 13.4 32 25 23 23 30 31 1.00 reference 0.89 (0.82-0.96) 0.0015 0.81 (0.75-0.89) < 0.0001 0.72 (0.63-0.82) < 0.0001 1.00 (0.87-1.16) 0.9908 1.06 (0.98-1.16) 0.1581 2.8 34.0 32.3 18.5 9.3 3.1 33 28 28 27 28 31 1.00 reference 0.85 (0.76-0.96) 0.0110 0.79 (0.70-0.90) 0.0002 0.76 (0.67-0.87) < 0.0001 0.81 (0.71-0.93) 0.0021 0.93 (0.79-1.09) 0.3712 38.8 26.5 13.1 21.7 25 28 31 31 1.00 reference 1.10 (1.04-1.16) 0.0006 1.20 (1.12-1.28) < 0.0001 1.32 (1.24-1.39) <.0001 16 0.0918 0.3668 0.6757 0.0099 0.6440 Page 193 of 290 Dialysis modality at listing Hemodialysis Peritoneal dialysis Unknown History of ASHD History of CHF History of CVA/TIA History of PVD History of hypertension History of diabetes History of COPD 83.4 12.8 3.8 11.0 15.0 3.6 5.4 74.8 36.4 2.1 28 31 27 36 32 35 37 28 32 39 1.00 reference 1.18 (1.10-1.25) < 0.0001 1.03 (0.92-1.16) 0.5911 1.13 (1.06-1.21) 0.0003 1.05 (0.99-1.12) 0.0795 1.12 (1.01-1.24) 0.0331 1.19 (1.09-1.29) < 0.0001 0.97 (0.92-1.02) 0.1975 1.13 (1.06-1.22) 0.0004 1.20 (1.05-1.37) 0.0093 ASHD, atherosclerotic heart disease; BMI, body mass index; CHF, congestive heart failure; CI, confidence interval; COPD, chronic obstructive pulmonary disease; CVA/TIA, cerebrovascular accident/transient ischemic attack; GN, glomerulonephritis; PVD, peripheral vascular disease. * Medicare patients added to kidney transplant waiting list 1999-2004, followed through December 31, 2006. 17 Page 194 of 290 Table 2. Hazard Ratios for Panel-Reactive Antibody Category in a Model Predicting Graft Failure PRA Category 0% 1-19% 20-79% 80-100% Patients Pretransplant Transfusion History 1.00 (reference) 1.04 (0.97-1.12) 1.16 (1.05-1.28) 1.41 (1.20-1.65) All 1.00 (reference) 1.05 (1.01-1.09) 1.18 (1.11-1.26) 1.30 (1.17-1.45) PRA, panel-reactive antibody. 18 No Pretransplant Transfusion History 1.00 (reference) 1.02 (0.96-1.08) 1.18 (1.07-1.30) 1.39 (1.00-1.43) Page 195 of 290 Figure Legends Figure 1. Cumulative incidence of first transfusion post-listing through 3 years, by age at listing. Figure 2. Association between postlisting transfusions and likelihood of transplant and death. 19 Page 196 of 290 Figure 3. Association between pretransplant blood transfusion and panel-reactive antibody (PRA) level at time of transplant by sex and pregnancy history. 20 Page 197 of 290 Figure 4. Association between panel-reactive antibody (PRA) level at time of transplant and outcomes within 3 years posttransplant. Patients who underwent transplant 1999-2004 (n = 69,991). 21 Page 198 of 290 J Am Soc Nephrol 15: 818–824, 2004 Leukocyte Reduction of Red Blood Cell Transfusions Does not Decrease Allosensitization Rates in Potential Kidney Transplant Candidates MARTIN KARPINSKI,* DENISE POCHINCO,† IGA DEMBINSKI,† WILLIE LAIDLAW,† JAMES ZACHARIAS,* and PETER NICKERSON*† *Department of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada; and †Immunogenetics Laboratory, Winnipeg Blood Center, Winnipeg, Manitoba, Canada Abstract. A significant proportion of potential kidney transplant candidates continue to periodically require blood transfusions that carry a risk of allosensitization. Leukocyte reduction (leukoreduction) of blood products has been proved to reduce transfusion-associated allosensitization in patients with hematologic malignancies; however, the effect in potential kidney transplant candidates is unknown. A total of 112 kidney transplant candidates who received red blood cell transfusions while on the transplant waiting list were identified retrospectively. Sixty received a transfusion before leukoreduction (nonLR), and 52 received a transfusion after the local implementation of universal leukoreduction of blood products (LR). There was no difference in transfusion-associated allosensitization rates in patients who received a transfusion during the two eras (non-LR 27% [16 of 60] versus LR 33% [17/52]; NS). Likewise, no difference was observed in subgroups identified as being at high risk of allosensitization (previous pregnancy, transplant, or five or more previous transfusions) or at low risk (no previous allogeneic exposures) (high risk: non-LR 52% versus LR 55%; low risk: non-LR 10% versus LR 8%). Multivariate analysis revealed previous pregnancy to be the only significant risk factor associated with transfusion-associated allosensitization (relative risk, 8.2; 95% confidence interval, 2.4 to 24.0; P ⫽ 0.0001). Leukoreduction, in particular, was not associated with any protective effect. In summary, leukoreduction of red blood cell transfusions does not confer any protection against transfusion-associated allosensitization for potential kidney transplant candidates. Physicians who care for patients with ESRD must continue to practice careful transfusion avoidance while alternative strategies to minimize transfusion associated allosensitization are sought. Despite the fact that recombinant erythropoietins have substantially decreased the need for transfusions in patients with ESRD, United Network for Organ Sharing (UNOS) data indicate that approximately 30% of wait-listed transplant candidates continue to receive red blood cell (RBC) transfusions at some point before transplantation (1, 2). In the past, some transplant programs administered deliberate pretransplant transfusions aimed at optimizing graft outcomes (i.e., the beneficial transfusion effect); however, more recent data indicate that this beneficial effect is no longer apparent, perhaps as a result of improving graft outcomes overall (2–5). Concerns of transfusion-associated allosensitization persist for potential transplant candidates, and it is likely that the majority of current transfusions are administered for other clinical indications. Allosensitization is associated with significant barriers to successful transplantation in patients with ESRD, including prolonged waiting times and inferior graft outcomes (6 – 8). Accordingly, any measure to limit allosensitization would represent a substantial advance for ESRD patients. Of the three principal causes of allosensitization—pregnancy, transplantation, and transfusions— only the last is perhaps modifiable. Leukocyte reduction of blood products (leukoreduction) reduces the transfused load of allogeneic leukocytes and has been proved to limit transfusion-associated allosensitization in patients with hematologic malignancies undergoing chemotherapy (9). The impact of RBC leukoreduction on allosensitization in ESRD patients is unknown. The few studies that have examined this practice either have been uncontrolled or have screened for allosensitization using technically inferior antiHLA antibody screening techniques (10, 11). Several recent studies have highlighted the superior sensitivity of flow cytometric anti-HLA antibody screening (FlowPRA) (12–14). We thus set out, in this retrospective cohort study, to use sensitive flow cytometric techniques to determine whether universal RBC leukoreduction has reduced the incidence of transfusionassociated allosensitization in potential kidney transplant candidates within our center. Received October 9, 2003. Accepted December 12, 2003. Correspondence to Dr. Martin Karpinski, University of Manitoba, Room GE421B, Health Sciences Centre, 820 Sherbrook Street, Winnipeg, MB, Canada R3A 1R9. Phone: 204-787-1524; Fax: 204-787-3326; E-mail:[email protected] 1046-6673/1503-0818 Journal of the American Society of Nephrology Copyright © 2004 by the American Society of Nephrology DOI: 10.1097/01.ASN.0000115399.80913.B1 Page 199 of 290 J Am Soc Nephrol 15: 818–824, 2004 Leukocyte Reduction and Allosensitization Rates Materials and Methods Universal Leukoreduction in Canada All blood products within Manitoba are distributed by a single agency, Canadian Blood Services, and since September 1999, all RBC units distributed within Manitoba have been leukoreduced in compliance with a nationwide Health Canada directive (15). This directive was issued in response to numerous lines of evidence indicating that leukoreduction of blood products likely reduces the incidence of several adverse transfusion reactions, including allosensitization. The Winnipeg Blood Centre now performs universal prestorage leukoreduction of RBC units with commercially available in-line filtration systems (Leukotrap WB and RC PL; Pall Medical, East Hills, NY), and the maximum accepted residual white blood cell (WBC) count is ⬍5 ⫻ 106/unit (normal WBC content approximately 5 ⫻ 109/unit). Internal quality control testing is applied to at least 1% of all units, and the actual residual WBC content is observed to be approximately 3 ⫻ 105/unit (unpublished data, Canadian Blood Services/Pall Corp.). Study Procedures This study was approved by the University of Manitoba Biomedical Research Ethics Board. The study population consisted of patients who were on the Manitoba renal transplant waiting list and had received RBC transfusions while wait-listed for transplantation. None of the transfusions administered was prescribed as deliberate pretransplant transfusions aimed at optimizing graft outcomes. Sera for antiHLA antibody screening on wait-listed patients were collected bimonthly during the period of study as well as 2 to 4 wk after any transfusion. Serum collection and transfusions are tracked meticulously by local transplant coordinators and Immunogenetics Laboratory technologists. Adult transplant candidates who received RBC transfusions between January 1996 and June 2003 thus were identified for retrospective study, and of 112 wait-listed ESRD patients identified, 60 received RBC units before the implementation of universal leukoreduction and 52 thereafter. Individuals who were broadly sensitized (FlowPRA ⱖ80%) before transfusion were excluded (n ⫽ 3). Patient data and transfusion records were abstracted from Manitoba Renal Program database. Anti-HLA Antibody Screening Transfusion-associated allosensitization was determined by antiHLA panel reactive antibody (PRA) screening pre- and posttransfusion. Sera were batched and then screened concurrently by both the anti-human globulin cytotoxicity technique (AHG-CDC PRA) and a flow cytometric technique (FlowPRA; OneLambda). Both screening assays were performed in the Immunogenetics Laboratory at the Winnipeg Blood Centre using standard techniques previously described (13). A patient was considered sensitized before a transfusion when the AHG-CDC PRA was ⱖ10% and/or when the FlowPRA assay revealed any detectable anti-HLA antibodies. Transfusion-associated sensitization was defined as the de novo appearance of a positive FlowPRA or as an increment in the FlowPRA value of ⱖ10%. Statistical Analyses Statistical analysis was performed using Statview 5.0 software (SAS Institute, Cary, NC). Values are reported as mean ⫾ SEM or, where indicated, as medians and ranges. The 2 test was used for comparison of categorical variables, whereas the t test was applied to comparisons of continuous variables. P ⱕ 0.05 was considered to be significant, and values ⬎0.10 are reported as nonsignificant (NS). In the multivariate analysis of risk factors for allosensitization, univariate risk factors associated with the outcome with P ⱕ 0.10 were allowed into the final model. These included a ⫹ve FlowPRA before transfusion, previous pregnancy, previous transplantation, previous transfusions, and the number of RBC units transfused in the episode under study. Leukoreduction was considered in the models despite being found to be nonsignificant in univariate analysis. Pregnancy and previous transfusions were considered as both categorical and continuous variables in the models analyzed. There was no demonstrable relationship between increasing numbers of pregnancies or transfusions and an increasing incidence of allosensitization, and the overall strength of the model was superior when these were considered as categorical variables. For these reasons, five or more previous transfusions was chosen as the transfusion variable, and this cutoff is also supported by previous studies (16). Results During the period of study, 112 individuals on the renal transplant waiting list received RBC transfusions and had appropriate pre- and posttransfusion serum samples collected for anti-HLA antibody screening. Sixty patients received a transfusion before universal leukoreduction (non-LR) and 52 thereafter (LR). There were significant baseline demographic differences between these two groups (Table 1). Patients who received leukoreduced transfusions were more likely to have Table 1. Baseline demographicsa Gender (male/female) Age when transfused Pregnancy No. of pregnancies (median, range) Previous transplant Previous RBC transfusion ⱖ5 Previous RBC transfusions ⫹ve FlowPRA pretransfusion Units transfused a RBC, red blood cell. 819 Pre-leukoreduction (n ⫽ 60) Leukoreduction (n ⫽ 52) P 39/21 40 ⫾ 2 13 2 (0–7) 6 18 (30%) 8 12 (20%) 3 ⫾ 0.4 28/24 42 ⫾ 2 20 2 (0–12) 8 33 (63%) 18 20 (38%) 3 ⫾ 0.3 NS NS NS NS NS ⬍0.001 0.008 0.03 NS 820 Page 200 of 290 Journal of the American Society of Nephrology J Am Soc Nephrol 15: 818–824, 2004 had a previous transfusion, were more likely to have received five or more RBC transfusions in the past, and were more likely to be allosensitized before the transfusion episode under examination (Table 1). Both groups received the same mean number of RBC units in the transfusion episode under study. Transfusion-Associated Allosensitization and Leukoreduction The overall rates of transfusion-associated allosensitization were 27% (16 of 60) in the population that received standard RBC units and 33% (17 of 52) in those who received leukoreduced RBC (NS; Table 2). Of the 33 individuals who met the definition of transfusion-associated allosensitization, 16 were previously unsensitized and 17 demonstrated a ⫹ve FlowPRA before transfusion. Fifteen of the 33 individuals developed isolated new HLA class I antibodies, six developed isolated class II antibodies, and 12 developed new class I and II antibodies. In previously unsensitized patients, the mean HLA class I and class II FlowPRA posttransfusion became 53 ⫾ 8% and 34 ⫾ 11%, respectively, whereas for previously sensitized patients, the mean increment in the class I and class II FlowPRA was 35% and 39%, respectively (class I pre, 44 ⫾ 8%; post, 79 ⫾ 5% [P ⬍ 0.01]; class II pre, 35 ⫾ 7%; post, 74 ⫾ 9% [P ⬍ 0.01]). There was no significant difference in either the degree (% ⌬PRA) or the nature of allosensitization (HLA class I and/or class II) that developed in patients who received standard versus leukoreduced transfusions (data not shown). Fifty-two of 112 patients were considered to be at high risk of transfusion-associated allosensitization on the basis of having had previous allogeneic exposures (previous pregnancy, previous transplantation, and five or more previous RBC transfusions), whereas 44 of 112 were considered to be at low risk (no previous allogeneic exposures). No effect of leukoreduction on allosensitization rates was seen in either of these two subgroups (high risk, 52% non-LR versus 55% LR [NS]; low-risk, 10% non-LR versus 8% LR [NS]; Table 2). AHG-CDC PRA was positive in only six (19%) of 32 patients who displayed a ⫹ve FlowPRA before transfusion. Similarly, AHG-CDC PRA detected new anti-HLA antibodies Table 2. Transfusion-associated allosensitization ratesa Transfusion-Associated Allosensitization P Preleukoreduction All patients (n ⫽ 112) High risk (n ⫽ 52) (previous pregnancy, Tx, ⱖ5 tf) Low risk (n ⫽ 44) (no previous pregnancy, Tx, or tf) a 16/60 (27%) 12/23 (52%) 3/31 (10%) Tx, transplant; tf, transfusion. Leukoreduction 17/52 (33%) NS 16/29 (55%) NS 1/13 (8%) NS in only 22 (67%) of the 33 patients who developed transfusionassociated allosensitization as determined by FlowPRA. Risk Factors for Transfusion-Associated Allosensitization In univariate analysis, factors that correlated with an increased likelihood of transfusion-associated allosensitization included a ⫹ve FlowPRA before transfusion, previous pregnancy, and five or more previous RBC transfusions (Table 3). In multivariate regression analysis, only previous pregnancy was associated with an increased risk of transfusion-associated allosensitization (relative risk, 8.2; 95% confidence interval, 2.8 to 24.0; P ⫽ 0.0001). Leukoreduction per se was not found to be protective in either univariate or multivariate analyses. Rates of allosensitization were similar for women who had a history of pregnancy and received either standard or leukoreduced transfusions (9 [69%] of 13 non-LR versus 11 [55%] of 20 LR; NS). Discussion A significant proportion of patients with ESRD are denied the full potential benefits of transplantation as a result of allosensitization. Allosensitized patients experience longer waiting times for finding compatible donors and are at risk of inferior graft outcomes transplanted (6). The barrier created by allosensitization is exemplified by the fact that approximately 30% of UNOS wait-listed renal transplant candidates are allosensitized yet only approximately 10% of transplants are performed in sensitized recipients (6). Of the three principal causes of allosensitization—pregnancy, previous transplantation, and transfusions— only the last is potentially modifiable. Nephrologists who care for ESRD patients are well aware of the risk of deleterious allosensitization and are careful to avoid unnecessary transfusions; however, this patient population remains at risk of periodically requiring allogeneic transfusions. The UNOS database indicates that approximately 30% of waitlisted transplant candidates continue to require blood transfusions at some point before transplantation (2). Recently, several groups reported their experience with novel immunosuppressive protocols incorporating intravenous immunoglobulin and plasmapheresis to enable the successful transplantation of sensitized recipients (17–19). Although encouraging, these protocols are available to only a small proportion of sensitized potential recipients and will likely do little to address the disparity in access to transplantation. Strategies to prevent allosensitization are likely to have a greater impact for ESRD patients. Leukoreduction of blood products reduces the load of allogeneic HLA in transfusions and has been proved to diminish allosensitization rates in patients who have hematologic malignancies undergoing chemotherapy (9). Several randomized trials have reported a benefit in this population (20 –27). The TRAP study, most notably, randomized ⬎200 patients with acute leukemia to receive leukoreduced RBC and either unmodified platelet preparations or irradiated, filtered, or apheresed platelet concentrates (27). Patients who received any of the modified platelet products were significantly less likely to Page 201 of 290 J Am Soc Nephrol 15: 818–824, 2004 Leukocyte Reduction and Allosensitization Rates 821 Table 3. Risk factors for transfusion-associated allosensitizationa Risk Factors (RR, 95% CI) FlowPRA ⫹ve pretransfusion Pregnancy Previous transplant ⱖ5 Previous transfusions Leukoreduction RBC units given (per unit) a Univariate P Multivariate P 4.5 (1.9–11) 7.8 (3.1–19.5) 2.8 (0.9–8.7) 5.1 (2.0–13.1) 0.5 (0.3–1.7) 1.1 (1.0–1.3) ⬍0.001 ⬍0.001 0.08 ⬍0.001 NS 0.10 2.4 (0.8–7.1) 8.2 (2.8–24) 2.4 (0.6–9.9) 2.6 (0.8–8.8) 2.0 (0.7–6.0) 1.1 (0.9–1.3) 0.10 0.0001 NS NS NS 0.10 RR, relative risk; CI, confidence interval. develop new anti-HLA antibodies and become refractory to platelet transfusions (17 to 21% versus 45%; P ⬍ 0.001). It must be noted, however, that studies that have examined leukoreduction and allosensitization have almost exclusively been performed in this patient population. Patients therein have also received large absolute numbers of transfusions with both platelet and RBC preparations (e.g., 14 ⫾ 11 platelet and 15 ⫾ 7 RBC transfusions in the TRAP study). There are comparatively few data on the impact of leukoreduction on allosensitization as a result of RBC transfusions in patients with ESRD. In the 1980s, SanFilippo et al. (10) conducted a randomized study transfusing renal transplant candidates with either standard or leukoreduced RBC units and found no difference in allosensitization. Importantly, there was no assessment of the extent and consistency to which leukoreduction was achieved with the techniques applied, and antiHLA antibody screening was performed with the AHG-CDC technique, which is less sensitive than current flow cytometric techniques. Christiaans et al. (11) examined potential transplant candidates who were given leukoreduced RBC transfusions and reported that de novo HLA class I antibodies developed in only 6% when screened by flow cytometry. This study, however, was uncontrolled and examined only low-risk, previously unsensitized patients. Limited literature also exists in other, nonrenal patient populations. Recently, Van de Watering et al. (28) randomized ⬎400 patients who were undergoing cardiac surgery to receive either standard or leukoreduced RBC transfusions and observed no difference in allosensitization rates in either unsensitized or previously sensitized patients. In the current study, we found no significant difference in the rate of transfusion-associated allosensitization in renal transplant candidates who received either standard or leukoreduced RBC transfusions (27% versus 33%, respectively; mean, 3 ⫾ 0.3 transfusions). Furthermore, similar rates and degrees (i.e., ⌬%PRA) of allosensitization were seen in both low-risk and high-risk patients who received transfusions of leukoreduced blood. The observed rate of allosensitization in high-risk patients is slightly higher than previously reported, and this is likely attributable to the superior sensitivity of the flow cytometric screening technique that we used. Studies using CDC techniques have reported allosensitization rates of approximately 30% in high-risk recipients, in contrast to the approximately 50% rate that we observed with FlowPRA screening (29 –31). These anti-HLA antibodies detected solely by flow cytometry are clinically relevant and have been increasingly associated with adverse outcomes posttransplantation (12–14, 31–34). We observed previous pregnancy to be the strongest risk factor for transfusion-associated allosensitization, a finding in keeping with previous observational studies (35, 36). Other allogeneic exposures, such as a previous transplant or previous transfusions, have also been reported to be risk factors for transfusion-associated allosensitization, although did not reach statistical significance in multivariate analysis herein (35, 36). This may represent a limitation of the size of our data set or, alternatively, an accurate representation of risk factors within our patient population. Notably, leukoreduction was not associated with any protective effect in either univariate or multivariate analysis. This study is retrospective, and ideally a randomized, controlled trial would be performed to evaluate the impact of leukoreduction on allosensitization in potential renal transplant recipients. This, however, is unlikely to occur. Many blood distribution organizations have in recent years adopted a policy of universal leukoreduction of blood products, and although not without controversy, this practice is now widespread (37, 38). In Canada and most of Europe, universal leukoreduction has been in place for several years, whereas approximately 70% of U.S. RBC units are currently leukoreduced before distribution. Organizations that monitor transfusion standards are unlikely to permit a change to previous blood-handling procedures; thus, retrospective studies such as this are necessary to investigate the effects of leukoreduction in patient populations other than those with hematologic malignancies (39). Several reasons may underlie why leukoreduction fails to diminish allosensitization rates in patients with ESRD. Individuals with ESRD are likely more immunocompetent than those who have hematologic malignancies and undergo treatment with myeloablative chemotherapy. This is supported by the similar sensitization rates in the two populations, despite the considerably greater overall exposure to allogeneic blood products in the latter. The mean number of RBC units transfused in the current study was 3 ⫾ 0.3, whereas patients who received leukoreduced products in the TRAP trial, in which approximately 20% became allosensitized, received fivefold 822 Page 202 of 290 Journal of the American Society of Nephrology this amount of platelet and RBC transfusions (27). Similarly, the degree of leukoreduction achieved with current techniques may be inadequate to prevent allosensitization in ESRD patients. Quality control assessments performed for Canadian Blood Services reveal reliable three to four logfold reductions in RBC unit leukocyte content. However, it may be that the residual leukocyte content (approximately 3 ⫻ 105/unit) represents a sufficient residual exposure to allogeneic HLA to induce an alloimmune response. Current leukoreduction techniques are similar in the degree of leukoreduction achieved, and there are no clinical data to favor current cutoff standards of approximately 1 to 5 ⫻ 106/unit for minimizing allosensitization (9, 38, 40 – 42). It is interesting that rodent models suggest that too great a degree of leukoreduction may in fact promote allosensitization, although the clinical relevance of this is unknown (43). Finally, leukocytes are not the sole source of allogeneic HLA in transfusions as soluble HLA and even RBC-bound HLA are present as well, and these are not diminished by leukoreduction (44 – 46). If standard leukoreduction fails to diminish allosensitization in potential renal transplant candidates, then alternative approaches must be sought. One approach that is occasionally used is the prescription of a brief course of immunosuppression beginning at the time of transfusion (e.g., with azathioprine or cyclosporine). This strategy has not been evaluated adequately, and its safety and generalizability are questionable (47– 49). Many patients who require transfusions are likely too acutely ill to be prescribed such therapy, which would presumably be necessary for a number of weeks peritransfusion. HLAmatched transfusions have in the past been successful in preventing allosensitization, and this strategy would be preferable but is limited by logistic concerns (50, 51). Existing blood distribution centers may have sizable numbers of HLAmatched donors on file (e.g., in bone marrow donor registries), but blood from HLA-typed individuals may not necessarily be on hand and may not be available in the time frame required for transfusion. Last, there is hope that less allogeneic blood substitutes or modified blood products will become available; however, this seems unlikely in the near future (52, 53). In summary, transfusions continue to be an important cause of allosensitization for potential kidney transplant recipients. Leukoreduction of RBC transfusions does not seem to reduce allosensitization rates in this patient population. The need for periodic transfusions persists for many patients on transplant waiting lists, and alternative transfusion strategies to prevent allosensitization must be found. J Am Soc Nephrol 15: 818–824, 2004 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. Acknowledgments This study was funded by grants from Canadian Blood Services (Canadian Blood Services Small Projects Fund) and the Kidney Foundation of Canada. This work was presented in abstract form at the 2003 American Transplant Congress in Washington DC, (ATC 2003 abstract #1356). References 1. Vella JP, O’Neill D, Atkins N, Donohoe JF, Walshe JJ: Sensitization to human leukocyte antigen before and after the intro- 15. 16. duction of erythropoietin. 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Nephrol Dial Transplant 3: 671– 676, 1988 Page 204 of 290 J Am Soc Nephrol 15: 818–824, 2004 50. Scornik JC, Salomon DR, Howard RJ, Pfaff WW: Prevention of transfusion-induced broad sensitization in renal transplant candidates. Transplantation 47: 617– 620, 1989 51. Lagaaij EL, Hennemann IP, Ruigrok M, de Haan MW, Persijn GG, Termijtelen A, Hendricks GF, Weimar W, Claas FH, van Rood JJ: Effect of one-HLA-DR-antigen-matched and completely HLA-DR-mismatched blood transfusions on survival of heart and kidney allografts. N Engl J Med 321: 701–705, 1989 52. Winslow RM: Blood substitutes. Curr Opin Hematol 9: 146 – 151, 2002 53. Goodnough LT, Shander A, Brecher ME: Transfusion medicine: Looking to the future. Lancet 361: 161–169, 2003 Page 205 of 290 CLINICAL RESEARCH www.jasn.org Preexisting Donor-Specific HLA Antibodies Predict Outcome in Kidney Transplantation Carmen Lefaucheur,* Alexandre Loupy,† Gary S. Hill,† Joao Andrade,‡ Dominique Nochy,† Corinne Antoine,* Chantal Gautreau,‡ Dominique Charron,‡ Denis Glotz,* and Caroline Suberbielle-Boissel‡ Departments of *Nephrology and Kidney Transplantation and ‡Immunology and Histocompatibility, Saint-Louis Hospital, Paris, France; and †Department of Histopathology, Georges Pompidou European Hospital, Paris, France ABSTRACT The clinical importance of preexisting HLA antibodies at the time of transplantation, identified by contemporary techniques, is not well understood. We conducted an observational study analyzing the association between preexisting donor-specific HLA antibodies (HLA-DSA) and incidence of acute antibody-mediated rejection (AMR) and survival of patients and grafts among 402 consecutive deceaseddonor kidney transplant recipients. We detected HLA-DSA using Luminex single-antigen assays on the peak reactive and current sera. All patients had a negative lymphocytotoxic cross-match test on the day of transplantation. We found that 8-year graft survival was significantly worse (61%) among patients with preexisting HLA-DSA compared with both sensitized patients without HLA-DSA (93%) and nonsensitized patients (84%). Peak HLA-DSA Luminex mean fluorescence intensity (MFI) predicted AMR better than current HLA-DSA MFI (P ⫽ 0.028). As MFI of the highest ranked HLA-DSA detected on peak serum increased, graft survival decreased and the relative risk for AMR increased: Patients with MFI ⬎6000 had ⬎100-fold higher risk for AMR than patients with MFI ⬍465 (relative risk 113; 95% confidence interval 31 to 414). The presence of HLA-DSA did not associate with patient survival. In conclusion, the risk for both AMR and graft loss directly correlates with peak HLA-DSA strength. Quantification of HLA antibodies allows stratification of immunologic risk, which should help guide selection of acceptable grafts for sensitized patients. J Am Soc Nephrol 21: 1398 –1406, 2010. doi: 10.1681/ASN.2009101065 Anti-HLA immunization constitutes an immunogenetic hurdle to transplantation, leading to increasingly protracted waiting times for sensitized kidney transplant recipients.1–3 In France, 25% of patients on the waiting list have a panel-reactive antibody (PRA) level of ⬎5%,4 and in the United States, 32% of patients awaiting transplantation are sensitized.1 Despite efforts to diminish the risk for sensitization by use of recombinant erythropoietin, leukocyte-depleted transfusions, and the cessation of pregraft transfusion protocols, the number of sensitized patients on transplant lists remains substantial. Moreover, loss of a previous graft has become the primary cause of anti-HLA sensitization. Patel and Terasaki5 in 1969 demonstrated the efficacy of complement-dependent lymphocytotoxic cross-match (CXM) in defining immunologic 1398 ISSN : 1046-6673/2108-1398 risk in renal transplantation. This became the standard method, still used today, for graft allocation. It became clear with time that it did not identify all preexisting donor-specific HLA antibodies (HLADSA). In recent years, techniques for detection of HLA antibodies have become more sensitive with the Received November 1, 2009. Accepted April 8, 2010. Published online ahead of print. Publication date available at www.jasn.org. C.S.-B. and D.G. contributed equally to this work. Correspondence: Dr. Carmen Lefaucheur, Département de Néphrologie et Transplantation Rénale, Hôpital Saint-Louis, 1 Avenue Claude Vellefaux, 75010 Paris, France. Phone: ⫹33-1-4249-96-08; Fax: ⫹33-1-42-49-96-08; E-mail: carmen.lefaucheur@ wanadoo.fr Copyright © 2010 by the American Society of Nephrology J Am Soc Nephrol 21: 1398–1406, 2010 Page 206 of 290 www.jasn.org introduction of solid-phase assays, including ELISA, and multiple bead– based technology, of which the Luminex-based assays are the most frequently used. The clinical impact of the antibodies detected by these more sensitive techniques has yet to be fully evaluated in terms of graft survival and definition of acceptable grafts.3 Studies of the clinical relevance of HLA-DSA in patients who receive a transplant with a negative CXM have been contradictory.6 –9 The ability to quantify these antibodies10 has added a dimension of complexity to the equation. The semiquantitative ELISA technique was used to advantage by our group in a cohort of 237 patients with renal transplants, showing an increase in the occurrence of acute antibody-mediated rejection (AMR) with increasing HLA-DSA levels detected in historic sera.11 The Luminex technique has been used in recent studies to choose the type of desensitization according to HLA-DSA strength12 and to determine acceptable HLA-DSA levels, allowing for successful kidney transplantation after desensitization.13 Forty years after the initial definition of immunologic risk by Terasaki and Patel, the introduction of these more sensitive techniques revives and carries to a new level the basic question of the clinical relevance of donor-specific anti-HLA antibodies and their integration into current strategies of transplantation. Indeed, no single study has compared the sensitivity, specificity, and positive predictive value (PPV) of classic or flow CXM, ELISA, and Luminex techniques in the prediction of AMR and graft survival. The objective of this study was to appraise the full clinical potential of HLA-DSAs detected before transplantation, with reference to the previously described ELISA single-antigen technique. We used the capacity of the Luminex technique to identify with precision and to quantify HLA-specific antibodies to grade increasing immunologic risk. This observational, single-center study of 402 consecutive deceased-donor kidney transplant patients examined the impact of the strength of HLA-DSA detected on historic and current sera on the risk for AMR occurrence and graft survival in deceaseddonor kidney graft patients. Our graft strategy was the current worldwide strategy based on a negative National Institutes of Health lymphocytotoxic CXM test. RESULTS Pretransplantation HLA Antibodies in Kidney Transplant Recipients Historic (Peak) Sera Among the 402 renal graft patients, 61 (15.2%) had a PRA level of ⱖ1%. A total of 118 (29.4%) patients had antibodies against class I or class II HLA on any pretransplantation serum and were considered as sensitized. Of these, 46 (39%) had HLA-DSA J Am Soc Nephrol 21: 1398 –1406, 2010 CLINICAL RESEARCH identified by ELISA and 83 (70.3%) had HLA-DSA identified by single-antigen flow-beads Luminex testing (peak SAFB HLA-DSA). Twenty-four (6%) patients presented a remote positive CXM: Nine patients with IgG T cell complement-dependent cytotoxicity CXM (CDCXM), two patients with IgG T cell antiglobulin enhanced complement-dependent cytotoxicity (AHG-CDCXM), two patients with B cell CXM, eight patients with IgG T and B cell CXM, and three patients with IgG B and T cell AHG-CDCXM. Figure 1 shows the distribution of peak SAFB HLA-DSAs according to the positivity/negativity of remote CXM (rCXM). Current Sera Seventy-six (18.9%) patients showed HLA-DSA at the time of transplantation (current SAFB HLA-DSA). The mean of the highest ranked SAFB HLA-DSA mean fluorescence intensity (MFI) detected on the current sera was 1293 ⫾ 200, not significantly different from that of HLA-DSAs detected on peak sera (1137 ⫾ 178; NS). There was no statistically significant intraindividual variation between the maximum SAFB HLA-DSAs of peak and current sera (P ⫽ 0.67). Survival Rates of Patients and Grafts Patients The mean follow-up time was 51.4 ⫾ 30.6 months (range 1.0 to 132.0 months). Patient 8-year survival was similar in nonsensitized patients, sensitized patients without peak SAFB HLADSA, and patients with peak SAFB HLA-DSA (90.2 versus 91.2 and 90.9%, respectively; P ⫽ 0.98). Grafts Five- and 8-year death-censored graft survivals were 89.2 and 83.6% in nonsensitized patients, 92.5 and 92.5% in sensitized Kidney transplant patients 01/1998-06/2006 N=402 r CXM + N=24 r CXM N=378 Peak DSA Luminex + N=18 Peak DSA Luminex N=6 Peak DSA Luminex + N=65 Peak DSA Luminex N=313 AMR N=13 AMR N=0 AMR N=16 AMR N=3 Figure 1. Distribution of donor-specific anti-HLA antibodies in kidney transplant recipients. rCXM⫹, patients with positive remote CDCXM; rCXM⫺, patients with negative remote CDCXM; peak HLA-DSA Luminex⫹, patients with donor-specific HLA antibodies detected by SAFB Luminex technique on the peak sera; peak HLA-DSA Luminex⫺, patients without donor-specific HLA antibodies detected by SAFB Luminex technique on the peak sera. Preformed Donor-Specific Antibodies 1399 Page 207 of 290 CLINICAL RESEARCH www.jasn.org Figure 2. The presence of HLA-DSAs on the highest rank pregraft serum associates with a significantly decreased graft survival (A), regardless of whether HLA-DSAs were class I or II (B). (C) The occurrence of acute AMR associates with a significantly decreased graft outcome. (D) Even in the absence of acute AMR, patients with preexisting HLA-DSAs have poorer graft survival as compared to patients without preexisting HLA-DSAs. Donor-specific HLA antibodies are detected by SAFB Luminex technique. P values are calculated with the use of the log-rank test. patients with no HLA-DSA recognized on peak, and 71.2 and 60.8% in patients with HLA-DSA, detected by Luminex technique on the peak sera. Kaplan-Meier analysis revealed that patients with peak SAFB HLA-DSA had a significantly lower graft survival as compared with sensitized patients with no HLA-DSA recognized and nonsensitized patients (P ⬍ 0.001, respectively; Figure 2A). There was no difference in graft survival analyzed according to the class of the maximum HLADSA identified on the peak sera (P ⫽ 0.8). Patients with HLA-DSA had poorer graft survival regardless of whether the maximum HLA-DSA was class I or II (P ⬍ 0.0002; Figure 2B). Acute AMR Episodes vival as compared with patients without HLA-DSA (69.5 versus 84.4% at 96 months respectively; P ⫽ 0.02; Figure 2D). Peak Sera Analysis of the PPV, sensitivity, and specificity for AMR of the various methods of identifying preexisting HLA-DSA is shown in Table 1. A positive rCXM has a high predictive performance of 54.2% with a high specificity at 97% but the lowest sensitivity at 40.6%. The Luminex technique has the highest sensitivity of these techniques (90.6%) but a low PPV of 34.9%, whereas the combination of Luminex and rCXM has the highest PPV of 72.2%. Current Sera The presence of SAFB HLA-DSA on the current serum has a PPV for AMR of 31.6% (sensitivity 75%, specificity 86.2%). Acute AMR occurred in 8% of kidney transplant patients. The 5- and 8-year graft survivals of patients who had an episode of AMR were 54.3 and Table 1. Relationship of pretransplantation anti-HLA antibody status to acute 45.5%, respectively, significantly worse AMR occurrence AMR than that of the remaining transplant popPositive Negative ulation (88.5 and 81.9%, respectively; P ⬍ Parameter Values Values PPV Sensitivity Specificity (n) (n) 0.0001; Figure 2C). The relative risk (RR) (%) (%) for graft loss for patients who had an epi- PRA ⱖ1% 61 341 36.1 68.8 89.5 sode of AMR was 4.1 (95% confidence in- rCXM 24 378 54.2 40.6 97.0 terval [CI] 2.2 to 7.7) as compared with pa- Peak ELISA HLA-DSA 46 356 41.3 59.4 92.7 83 319 34.9 90.6 85.4 tients without AMR. Even in patients Peak Luminex HLA-DSA 76 326 31.6 75.0 86.2 without any episode of AMR, the presence of Current Luminex HLA-DSA 18 384 72.2 40.6 98.7 SAFB HLA-DSA on the peak serum was still rCXM/peak Luminex HLA-DSA rCXM/current Luminex HLA-DSA 20 382 60.0 37.5 97.8 associated with a significantly lower graft sur1400 Journal of the American Society of Nephrology J Am Soc Nephrol 21: 1398 –1406, 2010 Page 208 of 290 www.jasn.org The incidence of AMR was 40% (24 of 60 patients) in patients with HLA-DSA detectable on both the peak serum and the current serum, versus 21.7% (five of 23 patients) in those with HLA-DSAs detectable on the peak serum but not on the current serum. The receiver operating characteristic (ROC) curve analyses of HLA-DSA strength in the prediction of AMR showed that maximum peak HLA-DSA MFI area under the curve (AUC) was significantly higher than that of maximum current HLADSA MFI (0.94 ⫾ 0.02 versus 0.86 ⫾ 0.04, respectively; P ⫽ 0.028; Figure 3). Graft Survival and Risk for AMR According to Quantification of Donor-Specific Anti-HLA Antibodies by SAFB Assays CLINICAL RESEARCH Table 2. RR for acute AMR according to the MFI of highest pregraft ranked DSA detected by Luminex (logistic regression) DSA MFImax class RR (95% CI) P ⱕ465 465 to 1500 1500 to 3000 3000 to 6000 ⬎6000 1.0 24.8 (4.6 to 134.8) 23.9 (3.5 to 160.8) 61.3 (11.5 to 327) 113.0 (30.8 to 414) ⬍0.001 0.001 ⬍0.001 ⬍0.001 ⬍3000. These results were also valid in patients without AMR (RR 2.8; 95% CI 1.5 to 16.9; P ⫽ 0.009; Figure 4B). In patients with MFIs ⬎3000, 57.1% of the graft losses at 1 year were due to AMR. ROC curve analysis determined that an MFI of 465 for the highest single or an MFI of 820 for total HLA-DSA MFI on the peak serum is associated with maximal specificity and sensitivity regarding the occurrence of AMR (AUC of 0.94 ⫾ 0.02 and 0.91 ⫾ 0.02, respectively; each P ⬍ 0.0001). The following analysis uses the highest single MFI values. The prevalence of AMR rises significantly with increasing MFI of highest pregraft HLA-DSA detected by Luminex technique on peak pregraft serum: 0.9% in patients with MFI ⬍465, 18.7% in those with MFI between 466 and 3000, 36.4% for MFI between 3001 and 6000, and 51.3% for patients with MFI ⬎6000 (2 ⫽ 138.1, P ⬍ 0.0001). The RR for AMR according to MFI is shown in Table 2. The 1-, 3-, and 8-year graft survivals decrease progressively with rising peak HLA-DSA MFI: 95.0, 93.8, and 82.5% in patients with MFI ⬍465; 100.0, 92.1, and 78.4% for patients with MFIs between 466 and 3000; and 85.0, 75.0, and 60.6% for patients with MFIs ⬎3000 (P ⬍ 0.001; Figure 4A). The graft survival in patients with MFIs ⬎3000 was significantly lower than that of patients with MFIs ⱕ3000 (P ⬍ 0.0001). The RR for graft loss for patients who underwent transplantation with peak HLA-DSAs ⬎3000 was 3.8 (95% CI 3.5 to 18.4; P ⬍ 0.0001) as compared with those with MFI HLA-DSA Figure 3. Peak HLA-DSA MFIs are better predictors of acute AMR than current HLA-DSA MFIs. Peak versus current ROC AUC was compared using 2 test with Bonferroni correction. J Am Soc Nephrol 21: 1398 –1406, 2010 Figure 4. The graft survival in patients with preexisting HLA-DSA MFIs ⬎3000 is significantly lower than in patients with HLA-DSA MFIs ⱕ3000. Kaplan-Meier estimates of graft survival according to the MFImax of preexisting HLA-DSAs in the entire cohort of kidney transplant patients (A) and in the subgroup of patients without acute AMR (B). Preformed Donor-Specific Antibodies 1401 Page 209 of 290 CLINICAL RESEARCH www.jasn.org Significance of the Association of SAFB HLA-DSA/ Remote CDCXM A total of 18 (21.7%) patients with peak SAFB HLA-DSA had a remote positive IgG T or B cell CXM. Their mean of the maximum HLA-DSA MFI was 7700.6 ⫾ 1139.0, not significantly different from the mean of the maximum HLA-DSA MFI of patients with negative rCXM (5782.6 ⫾ 672.3; NS). In patients with preformed HLA-DSA, the presence of peak complementfixing HLA-DSA on rCXM increased significantly the risk for AMR (peak HLA-DSA⫹/rCXM⫹ versus peak HLA-DSA⫹/ rCXM⫺; P ⫽ 0.0005) and significantly reduced graft survivals (P ⬍ 0.01). One- and 8-year graft survivals were 95.6 and 74.5% in patients with peak HLA-DSA⫹/rCXM⫺ and, respectively, 76.4 and 29.1% in patients with peak HLA-DSA⫹/ rCXM⫹. DISCUSSION This study shows the clinical relevance of precise immunologic characterization of patients before transplantation, using single-antigen flow-beads technology. Long-term outcomes of kidney grafts in patients with preexisting HLA-DSA detected by SAFB Luminex technique are significantly worse as compared with patients who undergo transplantation without HLA-DSA, confirming the recent results reported by Amico et al.9 Our study furthers those observations by showing that there is a gradation of the risk for AMR and of kidney graft survival according to the levels of HLA-DSA detected before transplantation. It also underlines the pertinence and importance of analysis of peak sera by SAFB techniques in defining the immunologic risk for patients on the waiting list. The high sensitivity of Luminex permits definition of the cutoff points above which antibody levels detected before the graft are clinically relevant. We have shown a dramatic increase in the risk for AMR with increasing levels of preexisting HLA-DSA above 465 as detected by Luminex. We have also shown that patients who undergo transplantation with HLA-DSA MFIs ⬎3000 have a 3.8 increased risk for graft loss as compared with patients who undergo transplantation with HLA-DSA MFIs ⬍3000. Our study also refines the current definition of immunologic risk3,9,14 in specifying the importance of the temporal element (peak and current serum) and of quantification of HLA-DSAs. The combination of different techniques for detecting HLA-DSA contributes to increasing their predictive performance. We have shown here that a precise estimate of immunologic risk before transplantation is possible, much earlier than any CXM assay and in advance of the point where grafts are accepted from deceased donors. This permits transfer of the focus from the simple identification of contraindication to transplantation (i.e., the CXM veto) to a personalized appraisal of immunologic risk and helps define the transplant strategy for any patient on the waiting list. This strategy should help in weighing the risk/benefit ratio on the basis of defined 1402 Journal of the American Society of Nephrology immunologic risk before transplantation. More generally, this early definition of immunologic risk should allow the transplant community to establish (1) an active policy for the transplantation of immunized patients, with priority programs for highly sensitized patients and the reduction of unnecessary shipping of organs, and (2) protocols for immunosuppression therapy and monitoring adapted to the immunologic risk of the recipients. Avoiding important confounding factors in graft survival, the design of this observational study has permitted an accurate analysis of the clinical relevance of HLA-DSAs. The Luminex analysis was performed retrospectively at the end of the study, avoiding possible bias in the decision to accept the graft and in modifications of immunosuppressive treatment. We have also excluded the patients for whom a pregraft conditioning was performed and patients for whom decisions were made taking into account sensitive techniques for detecting HLADSA (living donors, kidney-pancreas transplants). These data are important in the current context of widespread use of sensitive techniques for HLA-DSA detection but with practices varying considerably from one transplantation center to another. In recent years, a major change in renal transplantation has come from the recognition of the importance of AMR, recognized initially only as the cause of hyperacute rejection but now known to be responsible for acute and chronic lesions.15 Our study underlines that AMR is a major factor in the evolution of HLA-incompatible kidney transplants and is associated with higher rates of graft loss, even though interpretation of the long-term graft survival of patients with AMR suffers from variation of the approach to treatment of AMR over time. For treatment of AMR, we used a specific treatment based on intravenous Ig (IVIg) products known to have powerful immunomodulatory effects.16 Treatment of AMR has evolved from IVIg-based regimens to combination therapies using plasmapheresis, IVIg, and rituximab, leading to an amelioration of short-term graft survival of patients with AMR.17–20 The immunologic and histologic profiles of patients with AMR and poor prognosis have largely been defined.17,21 The concept of quantification of HLA-DSA posttreatment and the optimization of treatment according to the DSA levels17,22 should allow the histologic and immunologic evolution of AMR to be better defined over the long term as well. Importantly, our study shows that even in the absence of clinical AMR, the long-term graft course is worse in patients with preexisting HLA-DSA. The recently described entity of subclinical AMR23,24 in which progressive morphologic lesions are found on biopsy in the absence of overt clinical rejection may account for this different course. A recent study demonstrated that subclinical AMR is a frequent finding in patients with preformed HLA-DSA (31.1% at 3 months) and is associated with worse GFR at 1 year.25 These progressive lesions lead to chronic humoral rejection, first described in 200126 and now recognized to be a distinct cause of late graft dysfunction and loss.25,27,28 J Am Soc Nephrol 21: 1398 –1406, 2010 Page 210 of 290 www.jasn.org Our study shows the major impact that pregraft Luminexbased HLA-specific antibody screening is having on the field of transplantation. The Luminex technique is more sensitive in detection of HLA-DSAs than the other two techniques analyzed, ELISA and CDCXM. Luminex analysis permits pregraft characterization of the antibody profiles in sensitized patients and gives improved definition of safe (antibody-negative) and at-risk (antibody-positive) HLA specificities. The first step in the transplant strategy for sensitized patients is to define whether a graft with minimal immunologic risk is possible. Whenever possible, kidney transplantation should be performed in the absence of DSAs. Virtual cross-matching, recently promoted by the United Network for Organ Sharing,29 consists of selecting potential donors without HLA specificities against a recipient’s antibodies, predicting a negative CXM. The use of the virtual cross-matching permits expanding the geographic regions from which kidneys can be drawn and reduces waiting time and deaths on the waiting list.30 –32 It is, furthermore, a good indicator for reducing the risk of AMR.33 In practice, we must evaluate, for each sensitized patient on the waiting list, whether the listing of forbidden antigens permits a donor pool sufficient to ensure transplantation. For some highly sensitized patients, use of virtual cross-matching leads to an insufficient number of donors. Thus, alternatively, the access to transplantation for these patients can be augmented in three ways: Priority programs, desensitization regimens, or increased immunologic risk of transplantation with preexisting HLA-DSA. Priority programs such as the Eurotransplant “Acceptable Mismatch” program34 raise the probability for a hypersensitized patient to receive a kidney with a negative CXM,35 with excellent graft survivals.34 Desensitization protocols based on high-dosage IVIgs36 –38 have been used with success. Other therapies39,40 can be efficacious in desensitizing patients who are awaiting transplantation. Transplantation in the presence of HLA-DSA requires a careful estimation of the immunologic risk, as assessed by rCXMs and levels of antibodies detected by Luminex technique. For such patients at high immunologic risk, specific posttransplantation protocols41– 44 and close monitoring are indispensable. Access to and results of transplantation can therefore be improved in sensitized patients. The data presented in this article emphasize the importance of precisely characterizing the status of the anti-HLA pretransplantation immunization using sensitive techniques. This should allow optimization of donor immunologic selection, immunosuppressive regimen, and posttransplantation monitoring. CLINICAL RESEARCH 2006. Patients with multiple transplants (20 patients with combined liver-kidney transplants and 14 with pancreas-kidney transplants), living-donor transplants (36 patients), or pregraft conditioning (17 patients) and those for whom historic sera were not available for further research (24 patients) were excluded. All patients were followed up through January 2009. Data on the HLA typing of transplant donors and recipients and rCXM results were recorded on day 0 (day of transplantation). Data on survival of patients and grafts, AMR episodes, serum creatinine values, and posttransplantation immunosuppressive therapy were obtained at months 3 and 6; at years 1, 3, 5, and 8; and at the end of follow-up. Criteria for Accepting a Donor CXMs were performed by complement-dependent cytotoxicity (CDCXM) and T cell antiglobulin enhanced complement-dependent cytotoxicity (AHG-CDCXM) on lymph nodes and by complement-dependent cytotoxicity on separated B lymphocytes or spleen cells, according to National Institutes of Health recommendations. Peak and current sera were tested for all patients according to European Federation for Immunogenetics standards. Sera were tested both diluted and undiluted, with and without dithiothreitol. For all kidney transplant recipients, negative current IgG T cell and B cell CDCXMs were required. CXMs positive only for IgM were not considered as a contraindication to transplantation. Detection of HLA Antibodies HLA typing of transplant recipients was performed by molecular biology (Innolipa HLA typing kit; Innogenetics, Gent, Belgium). For all kidney transplant donors, HLA-A/B/DR/DQ tissue typing was performed using the microlymphocytotoxicity technique with One Lambda Inc. tissue-typing trays and was controlled by molecular biology. HLA-CW and HLA-DP typing of the donor was performed when an isolated HLA-CW or HLA-DP HLA-DSA was potentially present. All pretransplantation (historic) sera were screened by the most sensitive routine screening test available at the beginning of the study, ELISA assays (LAT-M; One Lambda, Canoga Park, CA), to determine the presence or absence of HLA class I or class II antibodies of the IgG isotype. HLA class I antibodies were then identified by complementdependent cytotoxicity on a frozen cell tray of 30 selected HLA-typed lymphocytes (Serascreen FCT30 Frozen Cell Trays; Gen Trak, Liberty, NC). PRAs of the IgG class directed against HLA class I molecules were calculated from this complement-dependent cytotoxicity assay. All patients in whom HLA antibodies were detected were screened for the presence of HLA-DSA in pretransplantation peak sera by two techniques: ELISA and SAFB Luminex assays. Peak serum was determined on the basis of the serum’s having the highest % PRA. The interval between the peak serum values and the actual transplantation was 29.4 ⫾ 11.8 months. CONCISE METHODS Detection of HLA-DSA Using ELISA Patients The study included 402 consecutive deceased-donor single-organ kidney transplants recipients who underwent transplantation in Saint-Louis Hospital (Paris, France) between January 1998 and June J Am Soc Nephrol 21: 1398 –1406, 2010 Identification of ELISA HLA-DSA class I was done using a high-definition single-antigen ELISA (LAT-1HD; One Lambda). For ELISA HLA-DSA class II identification, we performed an ELISA (LAT 2-40; One Lambda) test, which identified DR and DQ subtypes on a panel Preformed Donor-Specific Antibodies 1403 Page 211 of 290 CLINICAL RESEARCH www.jasn.org of purified HLA antigens. Both ELISA tests were performed as recommended by the manufacturer and described previously.11 Detection of HLA-DSA by ELISA on the peak sera was performed retrospectively between June and November 2006. tients received as additional treatment four plasmaphereses and two weekly doses of rituximab (375 mg/m2 body surface area; MabThera; Roche, Meylan, France).17 Statistical Analysis Detection of HLA-DSA Using SAFB on Luminex Platform Identification of class I and class II HLA-DSA by Luminex analysis (One Lambda) uses sets of 96 beads (class I) and 76 beads (class II), respectively; each bead is coated with a single HLA glycoprotein, permitting precise identification of antibody specificity. Presence of antibodies was detected using a goat anti-human IgG coupled with phycoerythrin. The fluorescence of each bead was detected by a reader (LABscan) and recorded as the MFI. All beads showing a normalized MFI ⬎300 were considered positive. For each patient, we recorded the number of HLA-DSA and the maximum HLA-DSA MFI defined as the highest ranked donor-specific bead. All current (day 0) sera were screened for the presence of HLADSA by class I and class II SAFB Luminex assays. Luminex analyses were performed retrospectively between January and March 2009 for the peak sera and in November 2009 for the current sera. Posttransplantation Induction Protocols and Maintenance Immunosuppressive Therapy Immunosuppression protocols were defined according to the immunologic risk, determined by the current system using lymphocytotoxic PRAs and T and B cell– based assays. Patients received induction therapy consisting of rabbit antithymocyte globulin (1.5 mg/kg per d for 10 days; Thymoglobulin; Genzyme) with maintenance immunosuppression consisting of tacrolimus (Prograf; Astellas) or cyclosporine (Neoral; Novartis), mycophenolate mofetil (CellCept; Roche), and steroids. Patients with remote positive IgG T and B cell CXM received IVIg at the time of transplantation (2 g/kg body wt on days 0 to 1, 20 to 21, and 40 to 41). Results are expressed as mean ⫾ SD for continuous variables, with the exception of MFIs, or which mean ⫾ SEM is used. Comparisons were based on the 2 test for categorical data and the t test for normally distributed continuous data. For parameters without Gaussian distribution (MFI), the Mann-Whitney U test was used. For individual HLA-DSA MFI evolution between peak and current sera, the Wilcoxon matched-pairs test was used. Death-censored graft survivals were calculated by Kaplan-Meier analysis. Differences between survivals were calculated by log-rank analysis. P ⬍ 0.05 was regarded as statistically significant. For studying the usefulness of HLA-DSA MFIs as a predictor of AMR, ROC curves were plotted to estimate the cutoff of MFImax HLA-DSA and total HLA-DSA MFIs in terms of yielding the highest sensitivity ⫹ specificity/2. We determined the AUC to evaluate its significance. For peak versus current ROC curves, AUC were compared using 2 test with Bonferroni correction. The association of AMR occurrence and MFI strength classes was determined by univariate logistic regression. The risk for graft failure according to the occurrence of AMR and HLA-DSA MFIs was determined using univariate Cox analyses. All tests were two-sided. All statistical analyses were performed using STATA 10.0 software (Stata Corp., College Station, TX). ACKNOWLEDGMENTS We thank Astellas France for the contribution to the statistical analysis. Diagnosis and Treatment of Acute AMR Episodes Among the patients with clinical acute graft dysfunction, three had episodes of borderline changes, 18 had episodes of acute T cell–mediated rejection (IA for six patients, IB for three patients, IIA for four patients, IIB for two patients, and III for three patients), and 32 patients had episodes of AMR. All rejection episodes were biopsyproven. Biopsy specimens were evaluated by light microscopy and immunofluorescence (C4d and Igs). Findings were graded according to the Banff ’07 classification.45 C4d was detected by a two-step indirect immunofluorescence method using a mAb specific for complement fragment C4d on frozen tissue (Quidel, Santa Clara, CA). All patients with AMR had characteristic histologic lesions delineated by the Banff classification of allograft rejection,46 positive C4d staining, and HLA-DSAs detected by SAFB assays at the time of diagnosis. All patients with AMR were treated with methylprednisolone pulses (500 mg/d for 3 days), with switch to tacrolimus for patients who were previously on cyclosporine and a protocol of high-dosage IVIg (2 g/kg, repeated every 3 weeks for four administrations). Between January 1998 and December 2003, eight patients received an additional treatment with plasma exchange (five patients) or muromonab-CD3 (OKT3; three patients). After January 2004, all pa1404 Journal of the American Society of Nephrology DISCLOSURES None. REFERENCES 1. Organ Procurement and Transplantation Network: Scientific registry of transplant recipients. Available at: http://optn.transplant.hrsa.gov/ data/. Accessed May 21, 2010 2. Cho YW, Cecka J: Crossmatch tests: An analysis of UNOS data from 1991 to 2000. In: Clinical Transplants, edited by Terasaki P, Los Angeles: UCLA Immunogenetics Center, 2001, pp 237–246 3. 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Jordan SC: Management of the highly HLA-sensitized patient: A novel role for intravenous gammaglobulin. Am J Transplant 2: 691– 692, 2002 38. Jordan SC, Tyan D, Stablein D, McIntosh M, Rose S, Vo A, Toyoda M, Davis C, Shapiro R, Adey D, Milliner D, Graff R, Steiner R, Ciancio G, Sahney S, Light J: Evaluation of intravenous immunoglobulin as an agent to lower allosensitization and improve transplantation in highly sensitized adult patients with end-stage renal disease: Report of the NIH IG02 trial. J Am Soc Nephrol 15: 3256 –3262, 2004 39. Stegall MD, Gloor J, Winters JL, Moore SB, Degoey S: A comparison of plasmapheresis versus high-dose IVIG desensitization in renal allo- Preformed Donor-Specific Antibodies 1405 Page 213 of 290 CLINICAL RESEARCH 40. 41. 42. 43. www.jasn.org graft recipients with high levels of donor specific alloantibody. Am J Transplant 6: 346 –351, 2006 Vo AA, Lukovsky M, Toyoda M, Wang J, Reinsmoen NL, Lai CH, Peng A, Villicana R, Jordan SC: Rituximab and intravenous immune globulin for desensitization during renal transplantation. N Engl J Med 359: 242–251, 2008 Akalin E, Bromberg JS: Intravenous immunoglobulin induction treatment in flow cytometry cross-match-positive kidney transplant recipients. Hum Immunol 66: 359 –363, 2005 Akalin E, Ames S, Sehgal V, Murphy B, Bromberg JS, Fotino M, Friedlander R: Intravenous immunoglobulin and thymoglobulin induction treatment in immunologically high-risk kidney transplant recipients. Transplantation 79: 742, 2005 Anglicheau D, Loupy A, Suberbielle C, Zuber J, Patey N, Noel LH, Cavalcanti R, Le Quintrec M, Audat F, Mejean A, Martinez F, MamzerBruneel MF, Thervet E, Legendre C: Posttransplant prophylactic intravenous immunoglobulin in kidney transplant patients at high immunological risk: A pilot study. Am J Transplant 7: 1185–1192, 2007 1406 Journal of the American Society of Nephrology 44. Burns JM, Cornell LD, Perry DK, Pollinger HS, Gloor JM, Kremers WK, Gandhi MJ, Dean PG, Stegall MD: Alloantibody levels and acute humoral rejection early after positive crossmatch kidney transplantation. Am J Transplant 8: 2684 –2694, 2008 45. Solez K, Colvin RB, Racusen LC, Haas M, Sis B, Mengel M, Halloran PF, Baldwin W, Banfi G, Collins AB, Cosio F, David DS, Drachenberg C, Einecke G, Fogo AB, Gibson IW, Glotz D, Iskandar SS, Kraus E, Lerut E, Mannon RB, Mihatsch M, Nankivell BJ, Nickeleit V, Papadimitriou JC, Randhawa P, Regele H, Renaudin K, Roberts I, Seron D, Smith RN, Valente M: Banff 07 classification of renal allograft pathology: Updates and future directions. Am J Transplant 8: 753–760, 2008 46. Racusen LC, Colvin RB, Solez K, Mihatsch MJ, Halloran PF, Campbell PM, Cecka MJ, Cosyns JP, Demetris AJ, Fishbein MC, Fogo A, Furness P, Gibson IW, Glotz D, Hayry P, Hunsickern L, Kashgarian M, Kerman R, Magil AJ, Montgomery R, Morozumi K, Nickeleit V, Randhawa P, Regele H, Seron D, Seshan S, Sund S, Trpkov K: Antibody-mediated rejection criteria: An addition to the Banff 97 classification of renal allograft rejection. Am J Transplant 3: 708 –714, 2003 J Am Soc Nephrol 21: 1398 –1406, 2010 Page 214 of 290 NEPHROLOGY 2010; 15, S101–S105 doi:10.1111/j.1440-1797.2009.01217.x Donor-specific transfusions Date written: June 2007 Final submission: October 2008 Author: Fiona Mackie GUIDELINES a. The best designed randomised controlled trial demonstrates no advantage of donor-specific transfusions (DSTs) in graft survival at 2 years or in the incidence of acute rejection. (Level II evidence) b. There is randomised controlled trial evidence (in a small trial) for a beneficial effect of DSTs in cyclosporinetreated recipients of one haplotype mismatch living related donations in terms of less acute rejection and lower serum creatinine in the short term. (Level II evidence) SUGGESTIONS FOR CLINICAL CARE (Suggestions are based on Level III and IV evidence) • The high risk of sensitisation does not justify the routine use of DSTs (Level III evidence) • A single pre-transplant DST is as effective as multiple DSTs. (Level III evidence) • The potential benefit of DST needs to be weighed against the risk of sensitisation (approximately 30%) and infection. • There is insufficient evidence on the use of DSTs to assist deletion of donor-specific antibodies pre-transplant to support their use. IMPLEMENTATION AND AUDIT No recommendation. BACKGROUND Maximising graft survival from living donors is a major goal in transplantation given the mismatch between the number of available donors and the ever-increasing number of recipients. Blood transfusion from living donors to the recipient prior to kidney transplantation was introduced several decades ago with the aim of improving graft outcome. However, with reduced acute rejection rates associated with newer immunosuppressive agents and recombinant erythropoietin use, DST is rarely practised. Nevertheless, modulating the immune response to the donor and inducing ‘pseudo-tolerance’ without having to rely heavily on immunosuppression continues to be a goal of transplantation medicine. When reviewing the evidence, it needs to be recognized that there may be fundamental differences between early reports of DST use and the DST of today; red blood cells are now washed and are essentially free of white blood cells – © 2010 The Author Journal compilation © 2010 Asian Pacific Society of Nephrology which may have been an important mediator of the observed effects. Furthermore, more recent literature suggests that the beneficial effect of tolerance develops only if the blood donor and recipient have one HLA haplotype or at least one HLA-B and one HLA-DR antigen in common.1 Many of the studies reviewed below do not specify these details. The purpose of these guidelines is to review the evidence on DST in living kidney donation (LKD) and to provide recommendations on when and whether its use is warranted. SEARCH STRATEGY Databases searched: MeSH terms and text words for kidney transplantation and living donor were combined with MeSH terms and text words for blood transfusion. The search was carried out in Medline (1966 – September Week 2, 2006). The Cochrane Renal Group Trials Register was also searched for trials not indexed in Medline. Date of search: 26 September 2006. Update search: Databases searched: MeSH terms and text words for kidney transplantation were combined with MeSH terms and text words for living donor and combined with MeSH terms and text words for open and laparoscopic nephrectomy. The search was carried out in Medline (1966 – March Week 1, 2009). The Cochrane Renal Group Trials Register was also searched for trials not indexed in Medline. Date of searches: 9 March 2009. WHAT IS THE EVIDENCE? Level II evidence The beneficial effect of DST in one haplotype mismatch living related donors was first suggested by Salvatierra et al.2 Since then, two prospective randomized trials have been reported.3,4 Page 215 of 290 S102 Alexander et al.3 compared patients given DST 24 hours prior to transplant and 7–10 days post-transplant (n = 115) with patients who did not receive DST (n = 97). The immunosuppression regimen was routine triple immunosuppression commenced post-transplant. All patients were -HLA non-identical (>50% had more than two Class I mismatches and more than one Class II mismatch). There was a similar distribution of HLA mismatch between the two groups. Biopsy-proven rejection episodes were seen more frequently in the DST group (81 vs 54 in non-DST) but this difference was not statistically significant. A significantly higher creatinine level was seen in the DST group at 7 and 14 days but this did not translate into a difference in 1- or 2-year graft survival. One of the primary outcomes of the study was the ability to withdraw steroid treatment; no significant difference was seen between the two groups for this outcome. There was no difference in adverse events between the two groups. Limitations of this study include the inclusion of a diverse degree of HLA matches and too small a sample size to adequately study the effect of DST for the different HLA matches. In a smaller prospective trial, Sharma et al.4 randomized living related recipients (n = 15) to receive DST (one transfusion 24 hours prior to transplant) or no DST (n = 15). All patients received cyclosporine 3 days prior to transplant and continued routine triple therapy post-transplant. In addition, all patients received third-party transfusions 2–3 weeks prior to transplantation to correct anaemia. Sharma et al. found a significantly greater incidence of acute rejection in the non-DST group (1.1 vs 0.26 per patient, P < 0.01). A significantly lower creatinine level was also seen in the DST group from 3 months to 12 months post-transplant (at 12 months, 1.12 vs 2.02 mg/dL, P < 0.05). However, there was no difference in graft survival in the short term (1 year). It is difficult to extrapolate results from this study to current practice because the degree of HLA match was not specified and patients in both groups received third-party transfusions to correct anaemia (prior to standard erythropoietin usage). Bordes-Aznar et al.5 reported a small randomized trial comparing the outcome of DST to cyclosporine and prednisone followed by azathioprine in living related recipients who were haploidentical but who had highly reactive mixed lymphocyte cultures (MLC). This group traditionally has a lower graft survival and is considered high risk. There was no difference in patient or graft survival at 1 year between the two groups (70% graft survival in both). In the DST group, 30% of potential donors were not able to be used because of sensitisation. Immunosuppression was not given during the transfusion periods. Bordes-Aznar et al. did not clearly state sample size or immunosuppression regimen, and the randomization method was not explained. Level III evidence In 2006, Marti et al.6 reported a prospective study of 61 potential allograft recipients (adults >16 years), both living related and unrelated, who received DSTs and compared them to carefully selected matched controls from the The CARI Guidelines Collaborative Transplant Study Group (CTS). The controls were matched for age, sex, related vs unrelated, original disease, cold ischemia time, number of transplants, year of transplant, time on dialysis and HLA match. All patients were on cyclosporin and prednisone with 31/55 also receiving either azathioprine or mycophenolate. There was no significant difference in induction therapy between the DST and matched control group. Although there was a trend to better allograft survival in the DST group (98% vs. 82%) this failed to reach statistical significance and when examined on an intention-to-treat basis, the 6-year graft survival of the DST group was 88.5%. There were no statistically significant differences in 1-year serum creatinine or treated acute rejection rate between the two groups. Of concern was the fact that 10% of patients (n = 6) in the DST group developed positive T cell crossmatches following the transfusions and living donation did not proceed. This study was underpowered to look at graft survival differences and historical controls were used. There were more pre-emptive transplants in the DST group (although time on dialysis was similar). Sonoda and Ishibashi7 retrospectively analyzed patients in the Japanese transplant registry. One HLA haplotype mismatch living related donor (LRD) patients (n = 1292) were analyzed in subgroups according to immunosuppression (cyclosporin n = 315; no cyclosporine n = 977) and DST transfusion (97/315 cyclosporin; 298/977 without cyclosporin). In the cyclosporin groups, the graft survival rate at 4 years for those with DST was 93.5%, compared with 76.2% for those with third-party transfusion (not DST) and 62.7% for those without transfusion. This improvement in graft survival was not seen in the noncyclosporin group, where the 4-year graft survival for DST was 73.3%, 73.2% for third-party transfusion and 69.0% for those with no transfusion. Davies et al.8 prospectively (not randomized) compared three different protocols for DST: 1. multiple pre-transplant DST with azathioprine during the period and oral cyclosporin post-transplant (n = 34), 2. multiple pre-transplant DST with azathioprine during this period and oral cyclosporin 1 day pre-transplant (n = 31), and 3. single pre-transplant DST 24–48 hours prior to transplant with pre-transplant intravenous cyclosporin (n = 21). All patients were LRD recipients with a 1 haplotype mismatch. There were no significant differences in recipient age, panel reactive antibodies (PRA) or the number of third-party transfusions between the three groups. Davies et al. found no significant differences in the acute rejection rate or in the 1-year patient or graft survival between the three groups. There was, however, a significantly greater incidence of CMV infection in Group 2 compared with the other groups (16% for Group 2 vs 0% for Groups 1 and 3). Satoh et al.9 retrospectively examined long term (3–13 years) graft survival in 52 one-haploidential living related first renal transplants conducted between 1983 and 1996. Twelve patients received prednisone, azathioprine and cyclosporin plus DST and 38 received prednisone, Page 216 of 290 S103 Living Kidney Donor azathioprine and cyclosporine alone. Recipients received 3 DSTs without immunosuppression. Historical controls were not extensively matched as in the study by Marti et al.6 and the DST group had signicantly lower donor age. There was no significant difference in acute rejection or long-term graft survival rates between the two groups. Two patients (16.7%) in the DST group developed donor specific antibodies which were subsequently removed by plasmapheresis and T and B cell crossmatches became negative. This study was important in demonstrating that longer term graft survival was not improved by DST, as one of the hypotheses regarding use of DSTs was that it may reduce chronic rejection and therefore alter long-term outcome. Otsuka et al.10 retrospectively analyzed 40 potential recipients of DST and cyclosporine, comparing them to a historical control who received a one haplotype matched living related kidney but no DST during the same period (n = 13). All patients received a calcineurin inhibitor. Cyclosporin was administered at the time of DST. There was no significant difference in graft survival rate at 5 and 10 years between the two groups, and no difference in acute rejection rates within 3 months after transplant. The sensitization rate was 7.5%, and one of the three patients who developed positive crossmatches could not proceed with living donation. One patient developed CMV infection as a consequence of the DST. Lezaic et al.11 retrospectively compared living related transplant recipients who had received DST with azathioprine cover (n = 19) to untransfused patients (n = 15) and 25 random polyinfused patients. Post-transplant immunosuppression consisted of azathioprine, cyclosporine and prednisone. Serum creatinine was significantly higher at 1 and 3 years in the non-transfused group compared with the DST and the randomly transfused group, despite the fact that there were no differences in the incidence of acute rejection or early graft function. There was also no difference in HLA mismatch, MLC reactivity and panel reactivity. This report provides little detail on the patients included or how the groups were selected and the numbers included are small. Three patients (15.7%) developed cross-reactivity with their donors in the DST group. Flye et al.12 examined the effect of three 200 mL aliquots of DSTs given biweekly with azathioprine cover in 163 oneor two haplotype-mismatch living related or living unrelated potential renal transplant recipients. Following transplantation, only prednisone and azathioprine were given. Their outcome was compared with a group of HLAidentical living recipients (n = 53) and a group of one-or two haplotype-mismatched living donor recipients (n = 54) treated with triple immunosuppression and induction therapy. Permanent T cell crossmatch sensitization occurred in 11 of the 163 patients (7%). Actual one- and five-year graft survivals were 94%, 100%, 100% and 72%, 85% and 71% for DST-treated groups with one HLA haplotype mismatched donors (n = 121), two HLA haplotype mismatched related donors (n = 14) and two haplotype-mismatched unrelated donors, respectively. This was comparable to the HLA identical group. No lymphoproliferative or CMV disease was seen in the DST group. In a retrospective paediatric study (Leone et al.13), the results of DST plus post-transplant immunosuppression with prednisone and azathioprine were compared with a routine triple immunosuppression group. All received haploidentical grafts. Three of 24 patients treated with DST had circulating cytotoxic antibodies to the donor. There was no difference in graft or patient survival at 1 year or in mean rejection episodes. However, there was less hospitalization and less severe rejection during the first 3 months in the cyclosporine (non-DST) group. Given the equivalent graft survival and the risk of recipient sensitization, the authors concluded that routine triple immunosuppression is preferable. Anderson et al.14 administered donor-specific whole blood or buffy coat in conjunction with azathioprine immunosuppression in 163 patients. Transient sensitization occurred in 2% and permanent sensitization in 7%. Over the 10 year duration, DST + azathioprine graft survival was similar to the HLA-identical sibling transplantation. The CMV sepsis rate was 2% and there was no occurrence of lymphoproliferative neoplasms. SUMMARY OF THE EVIDENCE Please refer to the enclosed evidence tables. WHAT DO THE OTHER GUIDELINES SAY? Kidney Disease Outcomes Quality Initiative: There is some evidence that donor-specific transfusion with living donor transplantation improves survival, but the decision to perform donor-specific transfusion must still be made on a case-by-case basis. Blood transfusions can induce antibodies to histocompatibility leukocyte antigens that can reduce the success of kidney transplantation; thus, transfusions generally should be avoided in patients awaiting a renal transplant. UK Renal Association: No recommendation. Canadian Society of Nephrology: No recommendation. European Best Practice Guidelines: No recommendation. International Guidelines: No recommendation. SUGGESTIONS FOR FUTURE RESEARCH No recommendation. CONFLICT OF INTEREST Fiona Mackie has no relevant financial affiliations that would cause a conflict of interest according to the conflict of interest statement set down by CARI. REFERENCES 1. van Twuyver E, Mooijaart RJ, ten Berge IJ et al. Pretransplantation blood transfusion revisited. N Engl J Med 1991; 325: 1210–3. Page 217 of 290 S104 2. Salvatierra O Jr, Vincenti F, Amend W et al. Deliberate donorspecific blood transfusions prior to living related renal transplantation. A new approach. Ann Surg 1980; 192: 534–52. 3. Alexander JW, Light JA, Donaldson LA et al. Evaluation of preand post-transplant donor-specific transfusion/cyclosporine A in non-HLA identical living donor kidney transplant recipients. Cooperative Clinical Trials in Transplantation Research Group. Transplantation 1999; 68: 1117–24. 4. Sharma RK, Rai PK, Kumar A et al. Role of preoperative donorspecific transfusion and cyclosporine in haplo-identical living related renal transplantation recipients. Nephron 1997; 75: 20–4. 5. Bordes-Aznar J, Odor A, Dib-Kuri A et al. Randomized clinical trial of cyclosporine or donor specific transfusion in high risk living-related donor transplantation. Transplant Proc 1987: 19: 2276–7. 6. Marti HP, Henschkowski J, Laux G et al. Effect of donor-specific transfusions on the outcome of renal allografts in the cyclosporine era. Transpl Int 2006; 19: 19–26. 7. Sonoda T, Ishibashi M. Donor-specific transfusion: a report of the Japanese Renal Transplant Registry. Clin Transpl 1987; 257–60. 8. Davies CB, Alexander JW, Cofer BR et al. Efficacy of a single pretransplant donor-specific transfusion and cyclosporin A admin- The CARI Guidelines 9. 10. 11. 12. 13. 14. istered 24 to 48 hours before one-haplotype-mismatched living related donor kidney transplant. Ann Surg 1992; 215: 618–25. Satoh S, Sugimura J, Omori S et al. Long-term graft survival with or without donor-specific transfusion in cyclosporine era in one haplo-identical living related renal transplant recipients beyond the first year: a 19 year experience. Tohoku J Exp Med 2002; 197: 201–7. Otsuka M, Yuzawa K, Takada Y et al. Long term results of donorspecific blood transfusion with cyclosporine in living related transplantation. Nephron 2001; 88: 144–8. Lezaic V, Jovicic S, Simic S et al. Donor-specific transfusion and renal allograft outcome. Nephron 2002; 92: 246–7. Flye MW, Burton K, Mohanakumar T et al. Donor-specific transfusions have long-term beneficial effects for human renal allografts. Transplantation 1995; 60: 1395–401. Leone MR, Alexander SR, Melvin T et al. A comparison of 2 protocols for living-related renal transplantation in children: donor-specific transfusions versus cyclosporine. J Urol 1990; 144: 721–3. Anderson CB, Brennan D, Keller C et al. Beneficial effects of donor-specific transfusions on long-term renal allograft function. Transplant Proc 1995; 27: 991–4. Page 218 of 290 S105 Living Kidney Donor APPENDICES Table 1 Characteristics of included studies Study ID (author, year) Intervention (experimental group) Intervention (control group) Follow up (months) N Study design Setting Participants Alexander et al. 19993 212 Randomised controlled clinical trial 8 centres, US Non-HLA identical living kidney transplant recipients Donor-specific transfusion No intervention 21 months Sharma et al. 19974 30 Randomised controlled clinical trial India Haplotypematched living related renal transplant recipients Donor-specific transfusion No intervention 13 to 18 months Main conclusions DST had no practical effect on patient or graft survival for up to 2 yrs, donor-specific responsiveness was more frequent in transfused patients DST and cyclosporine administered 24 h before Tx is effective in improving graft function and reducing acute rejection Table 2 Quality of randomised trials Study ID (author, year) Method of allocation concealment* Alexander et al. 19993 Sharma et al. 19974 Blinding Intention-to-treat analysis† Loss to follow up (%) (participants) (investigators) (outcome assessors) Central No No No No 5.8% Computer generated No No No Not stated 0.0% *Choose between: central; third party (e.g. pharmacy); sequentially labelled opaque sealed envelopes; alternation; not specified. † Choose between: yes; no; unclear. Table 3 Results for dichotomous outcomes Study ID (author, year) Outcomes Alexander Immunological et al. 19993 hyporesponsiveness Mortality at 2 yrs At least one rejection Severe steroidSharma et al. 19974 resistant rejections Mortality Graft loss Control group Intervention group (number of patients (number of patients with events/number of patients not with events/number exposed) of patients exposed) Relative risk (RR) [95% CI] Risk difference (RD) [95% CI] 0.15 (95%CI: 03.02, 1.11) -0.16 (95%CI: -0.28, -0.04) 1/37 9/49 4/115 60/115 2/97 44/97 13.69 (95%CI: 0.32, 9.01) 1.15 (95%CI: 0.87, 1.52) 0.01 (95%CI: -0.03, 0.06) 0.07 (95%CI: -0.07, 0.20) 2/15 3/15 0.67 (95%CI: 0.13, 3.44) -0.07 (95%CI: -0.33, 0.20) 1/15 2/15 2/15 3/15 0.50 (95%CI: 0.05, 4.94) 0.67 (95%CI: 0.13, 3.44) -0.07 (95%CI: -0.28, 0.15) -0.07 (95%CI: -0.33, 0.20) Page 219 of 290 0041-1337/02/7410-1377/0 TRANSPLANTATION Vol. 74, 1377–1381, No. 10, November 27, 2002 Printed in U.S.A. Copyright © 2002 by Lippincott Williams & Wilkins, Inc. WAITING TIME ON DIALYSIS AS THE STRONGEST MODIFIABLE RISK FACTOR FOR RENAL TRANSPLANT OUTCOMES A PAIRED DONOR KIDNEY ANALYSIS1 HERWIG-ULF MEIER-KRIESCHE2,3 Background. Waiting time on dialysis has been shown to be associated with worse outcomes after living and cadaveric transplantation. To validate and quantify end-stage renal disease (ESRD) time as an independent risk factor for kidney transplantation, we compared the outcome of paired donor kidneys, destined to patients who had ESRD more than 2 years compared to patients who had ESRD less than 6 months. Methods. We analyzed data available from the U.S. Renal Data System database between 1988 and 1998 by Kaplan-Meier estimates and Cox proportional hazards models to quantify the effect of ESRD time on paired cadaveric kidneys and on all cadaveric kidneys compared to living-donated kidneys. Results. Five- and 10-year unadjusted graft survival rates were significantly worse in paired kidney recipients who had undergone more than 24 months of dialysis (58% and 29%, respectively) compared to paired kidney recipients who had undergone less than 6 months of dialysis (78% and 63%, respectively; P<0.001 each). Ten-year overall adjusted graft survival for cadaveric transplants was 69% for preemptive transplants versus 39% for transplants after 24 months on dialysis. For living transplants, 10-year overall adjusted graft survival was 75% for preemptive transplants versus 49% for transplants after 24 month on dialysis. Conclusions. ESRD time is arguably the strongest independent modifiable risk factor for renal transplant outcomes. Part of the advantage of living-donor versus cadaveric-donor transplantation may be explained by waiting time. This effect is dominant enough that a cadaveric renal transplant recipient with an ESRD time less than 6 months has the equivalent graft survival of living donor transplant recipients who wait on dialysis for more than 2 years. Kidney transplantation is considered the treatment modality of choice for the majority of patients with end-stage-renal disease (ESRD). Preemptive transplantation has been advocated over transplantation after a period of dialysis. Initially this position was motivated by the observation that preemp- AND BRUCE KAPLAN2 tive renal transplant recipients were doing significantly better than patients who had undergone longer periods of maintenance dialysis (1, 2). These studies, however, could not exclude the potential selection bias of lower risk patients who obtain preemptive transplants and, therefore, could not directly implicate dialysis as a causal factor for the worse graft survival in transplants after maintenance dialysis. Evidence that time on dialysis in itself conferred a higher risk for graft loss after transplantation came initially from a single-center study by Cosio et al. who showed that increased time on dialysis before transplantation was associated with decreased patient and graft survival (3). The argument that time on dialysis itself is an independent risk factor for graft loss was strengthened by a subsequent retrospective study that was based on U.S. Renal Data System (USRDS) data that showed a clear dose effect of the detrimental effect of dialysis time on transplant outcomes not only for patient and graft survival but somewhat surprisingly also for death-censored graft survival in both cadaveric and living transplantation (4). In addition, this study found that the dose-dependent detrimental effect of dialysis time was proportional across different primary disease groups, making an argument against the hypothesis that the risk of increased ESRD time was only related to cumulative disease burden. Shortly thereafter, Mange et al. confirmed the better outcomes of living donated grafts in preemptive transplants versus patients on dialysis for longer periods of time (5). All previous studies looked at the relative impact of ESRD time on subsequent renal transplant outcomes, but they did not quantify this risk factor. In addition, it was difficult to quantify ESRD time as a risk factor unless proven to be independent of potential donor-related confounding factors. It is conceivable that part of the negative effect of ESRD time is related to poorer kidney grafts going to people who have been on the waiting list for longer times. For this reason, we decided to first investigate whether ESRD time is a risk factor for outcomes after kidney transplantation independent of donor factors and, if so, to subsequently quantify the absolute impact of ESRD time in cadaveric and living transplantation. Identifying ESRD time as a donor-independent risk factor would be of great significance because ESRD time would have to be considered a modifiable risk factor for kidney transplantation. To ascertain that ESRD time before kidney transplantation is a significant risk factor for graft survival independent of donor factors, we analyzed 2,405 kidney pairs harvested from the same donor and transplanted subsequently into one recipient with short ESRD time and the other in a recipient with long ESRD time (6). We also assessed overall 5- and 10-year graft survival rates by length of pretransplant dialysis in living versus cadaveric transplants in an attempt to 1 The data reported in this study have been supplied by the U.S. Renal Data System and the U.S. Scientific Renal Transplant Registry. The interpretation and reporting of these data are the responsibility of the authors and in no way represent an official policy or interpretation of the U.S. government. 2 Division of Nephrology, Hypertension and Transplantation, University of Florida, Gainesville, FL. 3 Address correspondence to: Herwig-Ulf Meier-Kriesche, M.D., Department of Internal Medicine, Division of Nephrology, Hypertension and Transplantation, 1600 SW Archer Road, Box 100224, Gainesville, FL 32610 – 0224. E-mail: [email protected]. Received 12 June 2002. Accepted 9 July 2002. DOI: 10.1097/01.TP.0000034632.77029.91 1377 Page 220 of 290 1378 TRANSPLANTATION quantify the relative impact of ESRD time versus living donation in determining long-term outcomes after transplantation. TABLE 1. Demographic characteristics of 2,405 recipients of paired kidneys with short compared to long ESRD MATERIALS AND METHODS We retrospectively analyzed data available from the USRDS for renal transplantations performed between 1988 and 1998 in the United States. In the database, we identified all cadaveric donors from whom two kidneys had been available for transplantation. We limited the analysis to kidney pairs that would go to primary adult, single-organ, renal transplant recipients. All pairs of which one kidney went to a six-antigen–matched recipient were excluded from the analysis. We then identified those kidney pairs that went to one recipient who had been on dialysis for less than 6 months, including preemptive transplants, and to the other recipient who had been on dialysis for more than 2 years. Study endpoints for this cohort of patients were overall graft survival, patient survival, death-censored graft survival, and patient survival with a functioning graft. We compared the study endpoints between the kidney pairs by Kaplan-Meier analysis and estimated whether observed differences were significant by the log-rank test. In addition, we used a Cox proportional hazards model to obtain adjusted survival rates for short versus long pretransplant ESRD time. These models were adjusted for known risk factors for graft and patient survival such as recipient demographics (but not donor demographics), HLA match, panel reactive antibody (PRA), immunosuppressive regimen, and delayed graft function. We also identified a second cohort of patients in whom all solitary adult first renal transplants between 1988 and 1998 were included. In this cohort of patients, we estimated differences in graft survival by Kaplan-Meier methods and calculated adjusted graft survival rates from a Cox proportional hazards model, which adjusted for the covariates and for the donor demographics. To evaluate the relative impact of waiting time on dialysis versus the affect of living versus cadaveric transplantation, we introduced an interaction term between ESRD time and transplant modality in the Cox model. In addition, we retrospectively analyzed 77,469 patients with ESRD who had been on the cadaveric renal transplant waiting list for at least 2 years between 1988 and 1998. We used a Cox nonproportional hazards model that used time to transplantation as the time-dependent covariate to estimate the risk for death associated with cadaveric renal transplantation compared to remaining on the waiting list (7). A probability of type 1 error less than 0.05 was considered the threshold of statistical significance. For multiple comparisons, we used Bonferroni methods to assess statistical significance. Statistical analysis was performed with SAS version 8.2 and SPSS version 11.0. Vol. 74, No. 10 N Donor age (years) Recipient age (years) Peak PRA (%) AB mismatch DR mismatch ESRD time (mo) Cold time Female recipients Female donor AA recipient AA donor Mechanical perfusion Antibody Induction MMF Neoral Prograf DGF Acute rejection ESRD time ⬍6 mo ESRD time ⬎24 mo 2,405 33.3⫾16.0 44.3⫾12.8 12.0⫾22.9 3.0⫾1.1 1.5⫾0.7 1.1⫾1.9 22.7⫾10.3 40.2% 38.1% 19.1% 10.8% 12.5% 33.3% 13.5% 13.6% 5.7% 20.1% 24.0% 2,405 33.3⫾16.0 47.3⫾12.5 17.3⫾26.7 3.1⫾1.0 1.5⫾0.7 51.2⫾34.6 22.8⫾10.2 41.4% 38.1% 33.2% 10.8% 12.4% 33.2% 14.4% 13.6% 5.6% 31.2% 27.4% P nsa ⬍0.01a ⬍0.01a nsa nsa ⬍0.01a nsa nsb nsb ⬍0.01b nsb nsb nsb nsb nsb nsb ⬍0.01b ⬍0.01b a t test. Chi-square test. MMF, mycophenolate mofetil; ns, not significant. b By Kaplan-Meier analysis, 5- and 10-year graft survival rates for paired kidneys (Fig. 1) were significantly worse in the patients who had undergone more than 24 months of dialysis (58% and 29%, respectively) compared to the patients who had been on dialysis for less than 6 months before transplantation (78% and 63%, respectively, P⬍0.001 each). The 5- and 10-year unadjusted death-censored graft survival rates for paired kidneys were 86% and 77%, respectively, in patients who had been transplanted early compared to 77% and 57%, respectively, in patients who were transplanted late (P⬍0.001 each). Five- and 10-year unadjusted overall patient survival for paired kidneys was 89% and 76%, respectively, in the group on dialysis less than 6 months compared to 76% and 43%, RESULTS Table 1 displays the demographics of recipients of paired kidneys in the short versus long ESRD time group. Donor demographics were identical between the groups because of each kidney pair selected, one kidney went to the short ESRD time group and one kidney went to the long ESRD time group. Recipient age was significantly higher in the patients who had been on dialysis for more than 2 years. Peak percent PRA before transplantation was significantly higher in patients in the long ESRD time group, but HLA matching was not significantly different between the groups. Cold ischemia time was virtually identical between the groups. Recipient gender distribution was similar, whereas African American recipients were observed more frequently in the long ESRD time group. Immunosuppressive therapy was equally distributed between the groups. Acute rejection and delayed graft function were both significantly more frequent in the long ESRD time group. FIGURE 1. Unadjusted graft survival in of 2,405 recipients of paired kidneys with short compared to long ESRD time. Page 221 of 290 November 27, 2002 1379 MEIER-KRIESCHE AND KAPLAN respectively, in the group on dialysis for more than 2 years (P⬍0.001 each). The 5- and 10-year adjusted graft survival for paired kidneys was 78% and 60%, respectively, in the short ESRD time group and 65% and 41%, respectively, in the long ESRD time group, and the relative risk for graft loss in the long ESRD time group was 1.73 (confidence interval 1.54 –1.95, P⬍0.001). The unadjusted graft survival of all cadaveric transplants between 1988 and 1998 is displayed in Figure 2. The 10-year overall unadjusted graft survival was 71% in the preemptive group, 49% in the 0 to 6 month dialysis group, 43% in the 6 to 12 month dialysis group, and 38% in the 12 to 24 month dialysis group and 35% in the patient group who had been on dialysis for more than 24 months. For all living donated kidneys, the 10-year overall unadjusted graft survival (Fig. 3) was 78% in the preemptive group, 62% in the 0 to 6 month dialysis group, 55% in the 6 to 12 month dialysis group, and 50% in the 12 to 24 month dialysis group and 48% in the patient group who had been on dialysis for more than 24 months. Relative risks for graft loss and 10-year adjusted graft survival rates in all cadaveric versus living transplants by ESRD time are displayed in Table 2. Preemptive cadaveric transplants were assigned the reference group in the interaction model to evaluate the relative impact of waiting time on cadaveric versus living transplants. Only living preemptive transplants did significantly better than preemptive cadaveric transplants (10-year adjusted graft survival rate of 75% vs. 69%, P⬍0.001). All other categories did significantly worse. Living transplants performed on patients who had been on dialysis up to 6 months were associated with a significantly higher risk of graft loss (relative risk⫽1.4, P⬍0.001) than preemptive cadaveric transplants with a projected 10-year graft survival of 62% versus 69%, respectively. Cadaveric transplants performed after more than 2 years of maintenance dialysis had the worst projected 10-year graft survival of 39%. The results of the Cox nonproportional hazards model that investigated the relative benefit of transplantation versus dialysis in patients on dialysis for at least 2 years is displayed in Figure 4. Of the 77,469 patients still on the waiting FIGURE 2. Unadjusted graft survival in 56,587 recipients of cadaveric transplants by length of dialysis treatment before transplant. FIGURE 3. Unadjusted graft survival in 21,836 recipients of living transplants by length of dialysis treatment before transplant. list after 2 years, 15,414 eventually underwent cadaveric renal transplantation whereas 61,055 remained on the waiting list until the study ended in June 1999. After 5 years, cadaveric renal transplantation was associated with a relative risk of 0.58 (P⬍0.001) compared to patients who remained on the cadaveric renal transplant waiting list. The evolution of the risk over time after cadaveric renal transplantation is displayed in Figure 4. DISCUSSION Our study demonstrates that waiting time on dialysis before transplantation is quantitatively one of the largest independent modifiable risk factors for graft loss after kidney transplantation. By analyzing pairs of donor kidneys that were transplanted in a recipient with short ESRD time and a recipient with long ESRD time, we can effectively exclude that part of the elevated risk for graft loss in the recipients who had undergone dialysis for a prolonged time was a result of donor characteristics not readily available from the database. Because of the national donor policy to share six-antigen– matched kidneys regardless of waiting time and across organ procurement organizations, more six-antigen matches can be found in preemptive cadaveric transplants. To prevent this potential bias in analyzing graft survival in the paired-kidney analysis, we excluded all kidney pairs of which any kidney went to a six-antigen–matched recipient. After this adjustment, the distribution of HLA matches was almost identical between recipients who received transplants early and those who received transplants late. Although we excluded a donor selection bias, it is conceivable that the worse unadjusted graft survival in the long ESRD time group was to a certain degree a result of higher risk recipients. On the other hand, higher PRA and more advanced recipient age are probably intrinsic characteristics of the patients with prolonged waiting time. When adjusting in the multivariate analysis for these risk factors, including African American recipients, we still observed an absolute difference of 12% worse graft survival in the long ESRD time recipients at 5 years and 19% worse graft survival at 10 years. This translates into a 15% relative difference in graft Page 222 of 290 1380 TRANSPLANTATION Vol. 74, No. 10 TABLE 2. Adjusted overall 10-year graft survival in cadaveric compared to living donor recipients by ESRD timea Cadaveric donor Living donor ESRD time Preemptive 0–6 mo 6–12 mo 12–24 mo ⬎24 mo RR (CI) Graft survival RR (CI) Graft survival 1 (Ref) 1.9 (1.8–2.0) 2.0 (1.9–2.1) 2.3 (2.1–2.4) 2.5 (2.3–2.6) 69% 49% 47% 43% 39% 0.84 (0.7–0.9) 1.4 (1.2–1.5) 1.6 (1.5–1.8) 1.8 (1.6–1.9) 2.1 (1.9–2.3) 75% 62% 56% 54% 49% a Calculated from Cox model adjusting for donor and recipient demographics, HLA matching, cold ischemia time, and immunosuppressive regimen. RR, relative risk; CI, confidence interval; Ref, reference group. FIGURE 4. Mortality risk of recipients of cadaveric renal transplants vs. wait-listed patients with ESRD who were on dialysis for at least 2 years. survival at 5 years and an overwhelming 32% relative difference at 10 years. These numbers quantify the real affect of length of ESRD time on graft survival and make ESRD time the largest potentially modifiable risk factor for renal transplant outcomes. The magnitude of the impact of ESRD time on outcomes is also reflected by the multivariate model including all patients, showing a 44% worse 10-year graft survival in cadaveric renal transplant recipients on dialysis for more than 2 years. Even in living donated kidneys, in which a potential donor selection bias is less likely, the overall adjusted 10year graft survival rate was 35% worse in recipients who had been on dialysis for prolonged periods of time. Note that the beneficial effect of a living transplant compared to a cadaveric transplant gradually fades when living transplants are performed after the patients have spent prolonged times on dialysis. By analyzing ESRD time versus transplant modality with an interaction term in the multivariate analysis, we were able to evaluate the relative benefit of living transplantation versus waiting time on dialysis. The 10-year–adjusted living graft survivals for transplants after more than 2 years of dialysis are similar to 10-year–adjusted cadaveric graft survival for transplants performed within the first 6 months of dialysis initiation. In fact, much of the overall beneficial effects of living donation on graft survival shown in literature (8, 9) seem to be attributable to the on average shorter ESRD times in these patients. At any given wait time, living donor recipients still have better graft survival rates than cadaveric donor recipients; however, this effect is smaller than the affect of waiting time. Of the basis of this data, waiting time on dialysis for a kidney transplant should be considered when determining the optimal choice of transplant type for a patient with near ESRD. Also, on the basis of this data, a cadaveric kidney transplant with an average waiting time of 2 years (U.S. average) yields a 48% worse 10-year graft survival compared to a preemptive living transplant. Obviously, waiting times vary widely across the United States, and pertinent information in regard to the locally expected waiting time and the resulting adjusted 10-year graft survival rates in living versus cadaveric transplantation can be obtained from Table 2. Despite the worse outcomes after transplantation in patients who received transplants after prolonged times on dialysis, the survival advantage of transplantation over dialysis was maintained even in the patients who had been on dialysis for more than 2 years. This suggests that whatever ongoing damage occurs to patients while they are on dialysis may be halted after transplantation. In fact, the relative long-term mortality benefit of transplantation over dialysis in this cohort of patients with ESRD times more than 2 years was similar to the survival benefit shown for the overall cohort of transplant recipients published by Wolfe et al. (7). The reason that an increased waiting time on dialysis is associated with decreased graft and patient survival can not be discerned from the data that we have presented. One possible explanation may be that, while dialysis is clearly a life-saving therapy, it is a less-than-perfect renal replacement modality and, thus, the longer patients wait on dialysis for a transplant the longer patients are exposed to the chronic effects of endstage renal failure and dialysis. It is well documented that patients on dialysis have alterations in the concentration of a number of substances (e.g., homocysteine, advanced glycosylation end products, and lipoproteins) that may predispose these patients to both cardiovascular and renal allograft vascular damages (10 –16). In addition, the poor nutrition, chronic inflammatory state, altered immunologic function, and inadequate clearance that often accompanies patients with ESRD on dialysis (17, 18) may predispose these patients to poorer tolerance to the immunosuppressive agents after transplantation. Therefore, patients on long-term dialysis may be at a disadvantaged state when they finally receive their transplant. CONCLUSION Transplant waiting time on dialysis is one of the strongest independent modifiable risk factors for renal transplant outcomes. A large part of the advantage of living versus cadav- Page 223 of 290 November 27, 2002 1381 BENITO ET AL. eric transplantation may also be explained by this phenomenon. This effect is dominant enough that a cadaveric renal transplant recipient with ESRD time less than 6 months has the equivalent graft survival as living-donor transplant recipients who wait on dialysis for more than 2 years. Organ allocation models geared toward improving outcomes in patients with ESRD will have to take into account that changes in average waiting time are a major factor in determining posttransplant graft and patient survival. Because waiting times are increasing as a result of the widening gap between the increase in the demand for organs and the increase in organ donations, improvements in cadaveric graft survival seen over the past decade may be difficult to match in the coming decade. 7. 8. 9. 10. 11. 12. Acknowledgment. The authors thank Suzanne C. Johnson who has helped with the editing and review of the paper. 13. REFERENCES 1. Roake JA, Cahill AP, Gray CM, et al. Preemptive cadaveric renal transplantation: clinical outcome. Transplantation 1996; 62:1411-1416. 2. Asderakis A, Augustine T, Dyer P, et al. Pre-emptive kidney transplantation: the attractive alternative. Nephrol Dial Transplant 1998; 13:17991803. 3. Cosio FG, Alamir A, Yim S, et al. Patient survival after renal transplantation, I: the impact of dialysis pre-transplant. Kidney Int 1998; 53:767772. 4. Meier-Kriesche HU, Port FK, Ojo AO, et al. Effect of waiting time on renal transplant outcome. Kidney Int 2000; 58:1311-1317. 5. Mange KC, Joffe MM, Feldman HI. Effect of the use or nonuse of long-term dialysis on the subsequent survival of renal transplants from living donors. N Engl J Med 2001; 344:726-731. 6. Mange KC, Cherikh WS, Maghirang J, et al. A comparison of the survival 14. 15. 16. 17. 18. of shipped and locally transplanted cadaveric renal allografts. N Engl J Med 2001; 345:1237-1242. Wolfe RA, Ashby VB, Milford EL, et al. Comparison of mortality in all patients on dialysis, patients on dialysis awaiting transplantation, and recipients of a first cadaveric transplant. N Engl J Med 1999; 341:17251730. Cecka JM. The UNOS Scientific Renal Transplant Registry: 2000. Clin Transpl 2000:1-18. Ojo AO, Port FK, Mauger EA, et al. Relative impact of donor type on renal allograft survival in black and white recipients. Am J Kidney Dis 1995; 25:623-628. Zimmermann J, Herrlinger S, Pruy A, et al. Inflammation enhances cardiovascular risk and mortality in hemodialysis patients. Kidney Int 1999; 55:648-658. Lowrie EG. Acute-phase inflammatory process contributes to malnutrition, anemia, and possibly other abnormalities in dialysis patients. Am J Kidney Dis 1998; 32:S105-S112. Wanner C, Zimmermann J, Quaschning T, et al. Inflammation, dyslipidemia and vascular risk factors in hemodialysis patients. Kidney Int Suppl 1997; 62:S53-S55. Gris JC, Branger B, Vecina F, et al. Increased cardiovascular risk factors and features of endothelial activation and dysfunction in dialyzed uremic patients. Kidney Int 1994; 46:807-813. Degenhardt TP, Grass L, Reddy S, et al. The serum concentration of the advanced glycation end- product N epsilon-(carboxymethyl)lysine is increased in uremia. Kidney Int 1997; 52:1064-1067. Hricik DE, Wu YC, Schulak A, et al. Disparate changes in plasma and tissue pentosidine levels after kidney and kidney-pancreas transplantation. Clin Transplant 1996; 10:568-573. Friedlander MA, Witko-Sarsat V, Nguyen AT, et al. The advanced glycation endproduct pentosidine and monocyte activation in uremia. Clin Nephrol 1996; 45:379-382. Kaufmann P, Smolle KH, Horina JH, et al. Impact of long-term hemodialysis on nutritional status in patients with end-stage renal failure. Clin Invest Med 1994; 72:754-761. Descamps-Latscha B, Herbelin A, Nguyen AT, et al. Immune system dysregulation in uremia. Semin Nephrol 1994; 14:253-260. 0041-1337/02/7410-1381/0 TRANSPLANTATION Copyright © 2002 by Lippincott Williams & Wilkins, Inc. Vol. 74, 1381–1386, No. 10, November 27, 2002 Printed in U.S.A. DIAGNOSIS AND TREATMENT OF LATENT TUBERCULOSIS INFECTION IN LIVER TRANSPLANT RECIPIENTS IN AN ENDEMIC AREA NATIVIDAD BENITO,1,3 OMAR SUED,1 ASUNCIÓN MORENO,1 JUAN PABLO HORCAJADA,1 JULIÀ GONZÁLEZ,1 MIQUEL NAVASA,2 AND ANTONI RIMOLA2 Background. Treatment of latent tuberculosis infection (LTBI) with isoniazid is recommended for transplant recipients with positive tuberculin skin test (TST). However, TST could be an imperfect identifier 1 Institut Clínic de Infeccions i Inmunologia, Hospital ClínicIDIBAPS Barcelona, University of Barcelona, Barcelona, Spain. 2 Institut Clínic de Malalties Digestives, Hospital Clínic-IDIBAPS Barcelona, University of Barcelona, Barcelona, Spain. 3 Address correspondence to: Dr. N. de Benito, Infectious Disease Service, Hospital Clínic, Villarroel, 170, 08036 Barcelona, Spain. E-mail: [email protected]. Received 8 February 2002. Accepted 9 July 2002. DOI: 10.1097/01.TP.0000034629.23838.5E of LTBI in this population. In addition, the risk of isoniazid hepatotoxicity could be high in liver transplant recipients (LTR). A retrospective cohort study was performed to evaluate the diagnosis and treatment of LTBI in LTR. Methods. Charts of all 547 patients who received primary liver transplantation at a University Hospital in Spain between 1988 and 1998 were reviewed. Results. TST was performed in 373 patients (71%) before transplantation. The result was positive in 89 (24%). The median follow-up after transplantation was 49 months. None of the TST-positive patients developed tuberculosis (TB), but 5 out of 284 patients with negative TST (1.76%) had active TB (Pⴝ0.6). Twenty- Page 224 of 290 Mechanisms of Disease Non-HLA transplantation immunity revealed by lymphocytotoxic antibodies Lancet 2005; 365: 1570–76 Gerhard Opelz for the Collaborative Transplant Study* See Comment page 1522 *Centres listed at the end of the paper Department of Transplantation Immunology, Institute of Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg, Germany (Prof G Opelz MD) Correspondence to: Prof Gerhard Opelz [email protected] Summary Background The presence of panel-reactive antibodies (PRA) against HLA antigens before transplantation is associated with early rejection of kidney grafts from cadaver donors. Transplants from HLA-identical sibling donors do not provide a target for antibodies to HLA antigens and should therefore not be affected by PRA. Methods Data from the Collaborative Transplant Study were used to examine the influence of PRA on graft survival. Uncensored graft survival and death-censored graft survival were calculated, and the data were analysed by multivariate Cox’s regression methods. Findings Among recipients of HLA-identical sibling transplants, 3001 patients with no PRA had significantly higher 10-year graft survival (72·4% [SE 1·1]) than 803 patients with 1–50% PRA (63·3% [2·5]; p=0·0006) or 244 patients with more than 50% PRA (55·5% [4·0]; p⬍0·0001). The effect of PRA became apparent after the first post-transplant year and was, therefore, strikingly different from the early steep decline in graft survival during the first year associated with PRA in recipients of cadaver kidneys. We could not discern whether graft loss was a direct effect of non-HLA humoral sensitisation or whether PRA served as an indicator of heightened immunity against non-HLA transplantation antigens. Interpretation PRA reactivity is strongly associated with long-term graft loss in kidney transplants from HLAidentical sibling donors. Panel-reactive antibodies Serum of a potential transplant recipient is tested for reaction with a panel of lymphocyte suspensions, generally obtained from random blood donors, in a dye-exclusion assay. The proportion of donors against whose lymphocytes a serum gives positive test reactions is recorded as a general measure of the patient’s state of presensitisation. Lymphocytotoxicity Commonly referred to in clinical transplant immunology as the serological dye-exclusion assay. When human lymphocytes are incubated with antibodies against HLA antigens in the presence of rabbit complement, the lymphocyte membrane is damaged and rendered permeable to eosin (cytotoxicity). In the absence of antibody, the cell membrane remains intact (dye exclusion). HLA Human leucocyte antigens are controlled by genetic loci located on chromosome 6 and expressed on all nucleated cells of the body. Part of the major histocompatibility complex (MHC). Known to be influential in transplantation of organs, bone marrow, and stem cells. 1570 Relevance to practice Our findings suggest that non-HLA immunity has a much stronger role in clinical transplantation than previously thought. In contrast to immunity against HLA mediated by antibodies present before transplantation, which leads to early acute graft rejection, non-HLA immunity is associated with chronic graft loss. The possibility of identifying recipients at increased risk of late graft loss before transplantation could be used to devise specific immunosuppressive strategies for these patients. Introduction Terasaki and colleagues first reported 30 years ago that kidney-transplant recipients whose serum contained lymphocytotoxic antibodies before transplantation were at increased risk of graft rejection.1 Their finding was confirmed in many subsequent studies, and now patients awaiting renal transplantation are routinely tested for lymphocytotoxic panel-reactive antibodies (PRA).2 The lymphocytotoxicity assay has certain drawbacks. There is no binding convention about the size of the cell panel used for testing, although most laboratories use commercial kits with frozen lymphocytes from 56 random donors. There is general acceptance that the results of the test system are suboptimally reproducible. Nevertheless, risk of rejection appears to rise as serum reactivity against the random lymphocyte test panel increases.3,4 PRA-positive serum samples contain antibodies against HLA antigens on lymphocytes,5,6 and graft survival in preimmunised recipients is assumed to be lower as the result of insufficient sensitivity in the pretransplant lymphocytotoxic cross-match test against donor lymphocytes. Much effort has therefore been spent on increasing the sensitivity of the cross-match assay so that weak antiHLA sensitisation can be detected,7,8 and the use of new techniques for pretransplant antibody testing based on highly sensitive, strictly HLA-specific ELISAs has been encouraged.9–11 Patients cannot form antibodies against their own HLA antigens; therefore they cannot form anti-HLA against lymphocytes of an HLA-identical sibling donor. In distinction from genetically identical twins, who share all genes and therefore do not require immunosuppression when tissues are transplanted between them, the common definition of HLA-identical siblings is that they are matched for both HLA chromosomes but mismatched at other chromosomes; thus, they can be of different sex, eye colour, and so on, as well as age. Since HLA chromosomes are inherited according to mendelian rules, the likelihood that two siblings will inherit identical HLA chromosomes from their parents is 25%. Although many other factors influence the outcome of kidney transplantation, transplants from HLA-identical sibling donors are recognised as a special category. They have significantly better success rates than transplants from HLAmismatched donors,12 and they are the standard against which the results of transplantation from other donor sources are compared. However, since rejection of HLAidentical sibling grafts commonly occurs if no immunosuppression is given, these recipients are www.thelancet.com Vol 365 April 30, 2005 Page 225 of 290 Mechanisms of Disease treated with immunosuppressive drugs, albeit at lower doses than recipients of grafts from cadaver donors. This need for immunosuppressive treatment shows that, aside from HLA, there must be other antigen systems that can cause transplant rejection. HLA-identical sibling transplants do not provide a target for anti-HLA, and PRA reactivity before transplantation should therefore not influence their success rate. We studied the influence of pretransplant PRA status on the long-term outcome of kidney grafts from HLAidentical sibling donors. reactivity.15 In the analysis of graft survival, all graft failures irrespective of cause (including death of the patient) were counted as failures. In the analysis of functional graft survival, deaths were censored. The Kruskal-Wallis and Mantel-Haenszel tests were used to estimate the statistical association between PRA reactivity and number of pretransplant blood transfusions, recipient’s sex, and proportion of retransplants. Immunosuppressive treatment (analysed by intention to treat) of patients with transplants from HLA-identical sibling donors included ciclosporin in Methods Cadaver kidney transplants Patients 100 Kidney transplants reported by 245 centres to the international Collaborative Transplant Study13 were analysed. Transplants were carried out between 1982, the year the study was initiated, and 2002. The centres included in this analysis provided written assurance of compliance with local ethical and consent guidelines and of patients’ consent for the use of data for scientific analysis. When consent from patients could not be obtained, care was taken to ensure that all data processing was carried out anonymously. p⬍0·0001 Grafts surviving (%) 90 80 70 No PRA 1–50% PRA ⬎50% PRA 60 50 40 Procedures 0 0 3 12 116 562 103 234 99 382 95 688 94 252 1–50% PRA 36 314 31 155 29 889 28 827 28 288 ⬎50% PRA 7610 6019 5724 5473 5349 9 12 No PRA HLA-identical sibling transplants 100 90 p=0·0831 80 70 60 50 40 0 0 www.thelancet.com Vol 365 April 30, 2005 9 Number of transplants 3 Statistical analysis Graft survival was calculated by Kaplan-Meier analysis.14 Statistical significance was assessed with the log rank test. Transplant outcome in relation to pretransplant antibody status was analysed by weighted regression analysis, in which the dependent variable was survival proportion, the independent variable was the degree of antibody reactivity, and the weight factor was the number of patients who had the given antibody 6 Time (months) Grafts surviving (%) A transplant was classed as HLA-identical if recipient and donor were reported to have identical HLA A, B, and DR antigens. 3681 first transplants and 367 retransplants from HLA-identical sibling donors formed the main study population for this analysis. 160 486 cadaver-donor transplants were analysed for comparison. HLA typing and testing for PRA was done at participating laboratories and reported to the study centre. The PRA reactivity of the last pretransplant serum sample was analysed. For 16 patients (five with no PRA, five with 1–50% PRA, and six with more than 50% PRA), positive pretransplant lymphocytotoxic crossmatches against lymphocytes of the kidney donor were reported, whereas all other patients had negative crossmatch results. All 16 patients with positive anti-donor cross-matches also had positive cross-match results against their own (autologous) lymphocytes, indicating that the positive cross-matches were the result of autoantibodies. Clinical follow-up was recorded at 3 months, 6 months, and 12 months, and yearly thereafter. 6 Time (months) Number of transplants 3001 2914 2864 2774 2765 1–50% PRA 803 774 766 744 741 ⬎50% PRA 244 235 229 223 215 No PRA Figure 1: 1-year graft survival analysis of kidney transplants from cadaver donors or HLA-identical sibling donors in relation to PRA 1571 Page 226 of 290 Mechanisms of Disease 2712 (67%) of the patients, tacrolimus in 122 (3%), and regimens without calcineurin inhibitors in 1214 (30%); there were no significant differences in success rates between the groups treated with these regimens. Multivariate Cox’s regression analysis16 was used to ascertain the effect of the covariates: transplant number (first or retransplant); year of transplantation; immunosuppressive regimen (calcineurin inhibitor or not); age, sex, and race of recipient and donor; original disease leading to endstage renal failure; number of pretransplant blood transfusions; and geographical location of the transplant centre (continent). The software packages SPSS (version 11.5) and SAS (version 8.2) were used. Role of the funding source No source of funding had any role in study design; collection, analysis, or interpretation of data; or in the writing of the report. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication. Results The differential effect of PRA on survival of transplants from cadaver donors or HLA-identical sibling donors during the first year after transplantation is shown in figure 1. As expected, a significant effect of PRA on graft survival was evident in cadaver transplants (p⬍0·0001), but no significant effect was noted in transplants from HLA-identical sibling donors (p=0·0831). PRA reactivity in cadaver-transplant recipients was associated with immunological graft loss rather than death of the patient. The calculation of death-censored functional graft survival, which provides an approximation of the rate of immunological graft rejection, gave almost the same result as that shown in figure 1 (p⬍0·0001). By contrast, PRA in HLA-identical sibling transplants affected neither graft nor functional survival. When the analysis was extended to 10 years of followup, however, a significant effect of PRA on graft survival became apparent in the analysis of HLA-identical sibling transplants (figure 2). At 10 years, the proportion of grafts surviving was 72·4% (SE 1·1) in patients with no PRA, 63·3% (2·5) in those with 1–50% PRA, and 55·5% (4·0) in those with more than 50% PRA (regression p⬍0·0001). The result was significant in both first transplants (p=0·0002) and retransplants (p=0·0001), and subset analysis showed significant associations for the transplant periods 1982–90 (p=0·0003) and 1991–2002 (p=0·005). Analysis of death-censored functional survival showed that the PRA effect was due to graft loss and not death of patients. The 10-year functional graft survival proportions were 82·5% (1·0), 75·3% (2·2), and 63·1% (4·0), for patients with no PRA, 1–50% PRA, and more than 50% PRA, respectively (p⬍0·0001; figure 3). The proportions of patients surviving at 10 years were 86·2% (0·9), 81·7% (2·0), and 81·9% (3·1) respectively (p=0·0266; data not shown). Multivariate Cox’s regression analysis showed that, compared with patients who were PRA-negative before transplantation, recipients with 1–50% PRA had a significantly increased risk of graft loss (relative risk 1·29 [95% CI 1·09–1·53], p=0·0033) and the risk was even higher in patients with more than 50% PRA (1·87 [1·47–2·37], p⬍0·0001). In the analysis of functional 100 90 90 Functional grafts surviving (%) 100 Grafts surviving (%) 80 No PRA 70 1–50% PRA 60 p⬍0·0001 ⬎50% PRA 50 1–50% PRA 70 60 ⬎50% PRA p⬍0·0001 50 40 40 0 0 0 2 4 6 Time (years) 8 10 0 2 4 6 Time (years) 8 10 Number of transplants Number of transplants 3001 2495 1929 1418 989 687 No PRA 3001 2495 1929 1418 989 687 1–50% PRA 803 647 514 362 249 158 1–50% PRA 803 647 514 362 249 158 ⬎50% PRA 244 192 149 111 84 65 ⬎50% PRA 244 192 149 111 84 65 No PRA Figure 2: 10-year follow-up of kidney grafts from HLA-identical sibling donors 1572 No PRA 80 Figure 3: Death-censored functional graft survival of HLA-identical sibling transplants www.thelancet.com Vol 365 April 30, 2005 Page 227 of 290 Mechanisms of Disease analysis of graft survival for the period after the first post-transplant year, when grafts subject to early antiHLA immunity had already been rejected (figure 1). Indeed, when the graft-survival analysis was restarted at 100% at 1 year after transplantation, a long-term effect of PRA became apparent in cadaver transplants (figure 5). We ruled out the possibility that the degree of HLA matching, which is known to affect long-term survival of cadaver transplants,12 might have caused the separation of the survival curves. The mean number of HLA A, B, Cadaver kidney transplants 100 90 p⬍0·0001 80 Grafts surviving (%) graft survival, the risk was significantly increased for patients with 1–50% PRA (1·26 [1·02–1·57], p=0·0282), and the result was highly significant for those with more than 50% PRA (2·23 [1·70–2·93], p⬍0·0001). The long-term evolution of the success of cadaver and HLA-identical sibling transplants differed substantially. PRA affected the survival proportion of cadaver-donor transplants primarily in the first few months after transplantation (figure 4). By contrast, transplants from HLA-identical siblings were not affected during the first year and the influence of PRA developed continuously during the 10-year follow-up, which suggests that different mechanisms were involved (figure 2). Owing to the intrafamilial pathway of inheritance of HLA chromosomes, the definition of HLA-matched transplants is not difficult in sibling settings. However, owing to the complexity of the HLA system and imperfect characterisation of HLA alleles in clinical typing for renal transplantation, identification of perfectly matched transplants in a registry series of cadaver kidney donors is impossible. At the level of allelic definition of HLA antigens,17 almost all cadaver transplants included in this analysis must be deemed HLA mismatched. With the available data, an analysis of perfectly matched cadaver transplants was therefore not possible. Nevertheless, one would assume that the nonHLA effect of PRA described in HLA-identical sibling grafts must also have a role in HLA-mismatched cadaver transplants, in addition to the anti-HLA effect shown in figure 1. We addressed this issue by doing a separate 70 No PRA 1–50% PRA ⬎50% PRA 60 50 40 0 0 2 4 6 8 10 Time (years) Number of transplants No PRA 88 389 83 720 62 516 44 887 30 819 1–50% PRA 26 676 25 005 18 402 12 842 8590 5586 2579 1817 1242 ⬎50% PRA 5075 4712 3582 20 674 100 HLA-identical sibling transplants 90 100 90 70 80 Grafts surviving (%) Grafts surviving (%) 80 60 50 p⬍0·0001 No PRA 1–50% PRA 40 ⬎50% PRA 70 p⬍0·0001 60 50 0 0 2 4 6 8 40 10 Time (years) 0 Number of transplants No PRA 1–50% PRA ⬎50% PRA 0 2 11 6562 83 720 62 516 44 887 30 819 20 674 36 314 25 005 18 402 12 842 7610 4712 3582 2579 8590 5586 1817 1242 Figure 4: Long-term (10-year) survival of cadaver kidney transplants according to pretransplant PRA Note the early separation of survival curves in the analysis of cadaver transplants, in contrast to the late separation in the analysis of HLA-identical sibling grafts (figure 2). www.thelancet.com Vol 365 April 30, 2005 4 6 8 10 Time (years) Number of transplants 2539 2495 1929 1418 989 687 1–50% PRA 664 647 514 362 249 158 ⬎50% PRA 199 192 149 111 84 65 No PRA Figure 5: Analysis of long-term effect of PRA starting at 1 year after transplantation 1573 Page 228 of 290 Mechanisms of Disease Characteristic Preformed PRA None (n=3001) Proportion female 1014 (34%) Proportion with retransplant 159 (5%) Mean (SE) pretransplant blood transfusions 3·47 (0·15) p 1–50% (n=803) ⬎50% (n=244) 361 (45%) 112 (14%) 6·01 (0·43) 154 (63%) 97 (40%) 10·7 (1·12) ⬍0·0001 ⬍0·0001 ⬍0·0001 Table: Association of preformed PRA with various characteristics of patients DR mismatches was similar in the groups with no PRA and 1–50% PRA (2·8 [SD 1·4] and 2·9 [1·4]), and recipients with more than 50% PRA even showed a significantly lower number of mismatches (2·3 [1·5]) than the other PRA groups (p⬍0·0001). Lymphocytotoxic antibodies in potential transplant recipients can be autoreactive in some cases. Such autoantibodies are believed to be the result of autoimmune processes in the recipient; they are commonly of the IgM subclass and are not generally associated with graft rejection.18,19 All 16 patients with positive pretransplant cross-match results had autoreactive antibodies. 14 of these patients had functioning grafts at 10 years, which shows that the antibodies were not involved in rejection. By contrast, antibodies to HLA antigens are mostly of the IgG class and the result of alloimmunisation in response to immunological challenge by pregnancy, blood transfusions, or rejection of a previous transplant. Our data suggest that the antibodies associated with late graft rejection in HLA-identical sibling transplants were alloantibodies. Although data on previous pregnancies were not available, we found significant associations of PRA reactivity with female sex and thus the possibility of pregnancy (p⬍0·0001), the number of pretransplant blood transfusions (p⬍0·0001), and the loss of a previous non-HLA-identical kidney transplant (p⬍0·0001; table). Discussion Minor histocompatibility antigens These antigens, less well defined than HLA, controlled by genes on other chromosomes, determine immunogenic epitopes able to elicit a T-cell response against transplanted cells or tissue. Influential in marrow/stem-cell transplantation but until now no proven influence on organtransplant survival. 1574 This study showed a highly significant association between the presence of lymphocytotoxic antibodies before transplantation and the outcome of kidney grafts from cadaver donors and HLA-identical sibling donors. Such an association was previously known in cadaver kidney transplantation, in which it has been attributed to unrecognised antibody reactivity against mismatched HLA antigens. However, the finding of a similar association for transplantation of organs between HLAidentical siblings was unexpected because the HLAantigen profile of recipient and donor is identical. In this special setting, no effect would be expected because PRA reactivity is generally believed to be directed against HLA antigens. The presence of weakly reactive antibodies to HLA antigens that went undetected in the pretransplant cross-match assay cannot explain the lower graft success rate observed in recipients of transplants from HLA-identical siblings. An association of graft rejection with the presence of lymphocytoxic antibodies before transplantation has been noted previously in bone-marrow transplantation from HLAidentical sibling donors.20 Apart from the main issue that antibodies to HLA antigens should not influence the outcome of transplants between HLA-identical siblings, the differing evolution of the PRA effect on graft survival suggests that cadaver and HLA-identical-sibling transplants were affected by different types of antibodies or different mechanisms of immunological rejection. The result for cadaver transplants is compatible with the concept that HLA antibodies present in the recipient’s circulation at the time of transplantation reacted with mismatched HLA antigens on donor tissue. These antibody reactions were probably weak, because they went undetected in the pretransplant cross-match assay and did not lead to immediate graft failure from hyperacute rejection. Irreversible rejection, however, occurred within a few weeks or months as shown by the early decline of graft survival curves in presensitised patients (figure 1). The survival curves for HLAidentical-sibling transplants, by contrast, declined very slowly, indicating a much later immunological event (figure 2). This differentiation in early and late graft loss also argues against the unlikely possibility that graft failure in the sibling group might have been due to incorrect HLA typing; had HLA mismatches been present among the HLA-identical siblings, early graft losses as a result of antibody-mediated rejection would have been expected. All sibling donors and recipients analysed in this study were identical at the HLA A, B, and DR loci, the histocompatibility loci established to be influential in clinical kidney transplantation. Although the presence of incompatibilities at other loci within the HLA region (eg, DQ, DP) cannot be excluded, the likelihood that such incompatibilities existed can be estimated at less than 3%. Thus, the chance that the results of this study were influenced to an important extent is very small. The targets for antibodies causing late rejections could be so-called minor histocompatibility antigens, which are not coded for in the HLA genetic region and have been shown to influence the outcome of bone-marrow transplants.21 Antibodies against these antigens might not lead to acute rejection of kidney grafts but to protracted chronic rejection. Since decreased graft survival was associated with PRA reactivity, two possible hypotheses are that antibodies to minor histocompatibility antigens occur frequently together with anti-HLA, or that cross-reactivity of anti-HLA with epitopes on minor histocompatibility antigens might induce late graft rejection. Another possibility is that PRA reactivity does not signal the existence of antibodies against minor histocompatibility antigens but serves as an indicator of a generally increased state of immune responsiveness due to allogeneic preimmunisation, and that www.thelancet.com Vol 365 April 30, 2005 Page 229 of 290 Mechanisms of Disease incompatibilities for minor histocompatibility antigens might exert a strong but protracted graft-damaging influence in patients with heightened immunity. Aside from acute rejections of cadaver kidneys mediated by antibodies to HLA antigens, delayed rejections would not be directly mediated by the antibodies detected in pretransplant serum, thus explaining the differential time profiles of rejection due to “major” HLA incompatibilities (cadaver transplants with HLA mismatches) or “minor” non-HLA incompatibilities (a proportion of HLA-identical-sibling and cadaver transplants). In cadaver-transplant recipients with heightened immunological reactivity against both major and minor incompatibilities, the grafts would fail early. The finding that a substantial proportion of sibling transplants failed even in the absence of any detectable antibody reactivity (figure 2) shows that the process described here is the cause of only some, not all, graft failures. The results presented here have important fundamental and practical implications. The study has shown that non-HLA immunity contributes substantially to long-term kidney-transplant failure. When the long-term results for kidney recipients with PRA were examined over 10 years of follow-up, the influence of non-HLA-directed immunity was of similar magnitude to that of antibodies against HLA (figures 2 and 4). The study shows the importance of characterising the non-HLA antigens that bring about graft loss. However, because it was based on registry data, serum and cells from recipients and donors are not available for in-vitro studies. Prospective collection of biological material from donors and recipients of HLAidentical sibling transplants will be needed for further progress on this issue. If future research is successful, many of the late graft failures attributable to non-HLA effects might be avoidable. For the time being, the fact that HLA-identical siblings at increased risk of late graft loss can be identified before transplantation could be used to devise specific immunosuppressive strategies for these patients. Another interesting point arising from these results is the implication that the current worldwide trend towards replacement of pretransplant antibody testing in the complement-dependent lymphocytotoxicity assay with strictly HLA-specific ELISA testing might be counterproductive. ELISA assays have the advantage of better reproducibility than the complement-dependent cytotoxicity method, and ELISA testing at increased sensitivity with strict anti-HLA specificity is widely expected to lead to better clinical transplant results.9–11 Direct comparison of transplant outcome in relation to pretransplant antibody testing with lymphocytotoxicity or HLA-specific ELISA, however, did not show a convincing advantage for either method and provided evidence that some serum samples contained ELISAnon-reactive antibodies that were associated with kidney www.thelancet.com Vol 365 April 30, 2005 graft rejection.22 The results of this study suggest that an important part of the antibody range might be missed if pretransplant serum testing were limited to HLAspecific ELISA. Although the introduction of ELISA techniques has greatly improved ability to characterise antibodies to HLA, the additional non-HLA reactions detected in the classic lymphocytotoxicity assay seem to be clinically highly relevant. Although the exact immunological mechanisms involved remain to be discovered, caution should be used in modifying pretransplant screening procedures without further knowledge about the effect of lymphocytotoxic antibodies on long-term outcome. For the time being, use of both ELISA and cytotoxicity assays in parallel for pretransplant testing seems wise to allow a separation of anti-HLA from anti-non-HLA activities. Our results also suggest that the introduction of highly sensitive, strictly HLA-specific ELISA-based pretransplant cross-match assays23 has only a limited potential for improving transplant outcome. Although these tests can be expected to lower further the incidence of HLA-antibodymediated rejections, they will not affect the substantial rate of late rejections attributable to immunity unrelated to HLA. Contributors Gerhard Opelz initiated and coordinated the study and wrote the report. Participating centres Argentina—Buenos Aires (3); Mar del Plata; Rosario. Australia— Adelaide; Brisbane; Heidelberg; Hobart; Melbourne; Newcastle; Perth; Sydney (7). Austria—Graz; Innsbruck; Linz; Vienna. Belgium—Leuven (2); Liege. Brazil—Belo Horizonte (2); Maceio; Pato Branco; Porto Alegre (2); Ribeirao Preto; Rio de Janeiro (2); Sao Paulo (4). Canada— Quebec; Toronto; Vancouver; Winnipeg. Chile—Santiago (2); Valdivia. Colombia—Medellin. Croatia—Rijeka; Zagreb. Egypt—Cairo (2); Mansoura. Finland—Helsinki. France—Lille; Lyon; Nancy; Nantes; Paris; Poitiers; Reims; Rennes; St Etienne; Toulouse. Germany— Aachen; Augsburg; Berlin (2); Bochum; Bonn; Bremen; Cologne (2); Düsseldorf; Erlangen; Frankfurt; Freiburg; Fulda; Giessen; Göttingen; Halle; Hann-Muenden; Hannover; Heidelberg; Homburg-Saar; Jena (2); Kaiserslautern; Kiel; Lübeck; Mainz; Mannheim; Marburg; Münster; Munich; Regensburg; Rostock; Stuttgart; Tübingen; Ulm; Würzburg. Greece—Thessaloniki. Hong Kong—Hong Kong (8). Hungary— Budapest; Debrecen; Pecs; Szeged. India—New Delhi. Iran—Shiraz; Tehran. Ireland—Dublin. Israel—Petach Tikva. Italy—Brescia; Cagliari; Florence; Genova (2); Milan (4); Padova (2); Treviso; Turin; Udine; Varese; Verona; Vicenza. Korea—Seoul. Lithuania—Kaunas; Vilnius. Mexico—Guadalajara (2); Mexico City. Netherlands—Nijmegen. New Zealand—Auckland; Christchurch; Hamilton; Wellington. Pakistan— Islamabad; Karachi. Peru—Lima. Philippines—Manila. Poland— Katowice. Russia—Moscow. Slovakia—Martin. Slovenia—Ljubljana. South Africa—Cape Town (5). Spain—Badalona; Barcelona (6); Madrid (5); Oviedo; Pamplona; Santander; Valencia (3). Sweden—Goteborg; Malmo-Lund; Uppsala. Switzerland—Basel; Bern; Geneva; Lausanne; St Gallen; Zurich. Turkey—Ankara (2); Antalya; Izmir (2). UK—Aberdeen; Belfast; Birmingham; Brighton; Bristol; Cambridge; Cardiff; Carshalton; Coventry; Dresden; Dundee; Edinburgh; Glasgow (2); Kent; Leeds; Leicester; Liverpool; London (9); Manchester; Newcastle upon Tyne; Nottingham; Oxford; Plymouth; Portsmouth; Sheffield. USA— Cincinnati; Dallas (3); Grand Rapids; Kansas City (3); New Orleans; New York (2); Omaha; Orlando; Portland (2); Shreveport; Stanford; Valhalla. Venezuela—Caracas; Maracaibo. Conflict of interest statement I declare that I have no conflict of interest. 1575 Page 230 of 290 Mechanisms of Disease Acknowledgments I thank staff members at 245 transplant centres who provided data for this study for their generous support, and Bernd Doehler for valuable assistance with statistical analysis. References 1 Terasaki PI, Mickey MR, Kreisler M. Presensitization and kidney transplant failure. Postgrad Med J 1971; 47: 89–92. 2 Terasaki PI, McClelland JD. Microdroplet assay of human serum cytotoxins. Nature 1964; 204: 998–1000. 3 Opelz G, for the Collaborative Transplant Study. Kidney transplantation in sensitized patients. Transplant Proc 1987; 19: 3737–41. 4 Katznelson S, Bhaduri S, Cecka MJ. Clinical aspects of sensitization. In: Cecka JM, Terasaki PI, eds. Clinical transplants 1997. Los Angeles: UCLA Tissue Typing Laboratory, 1998: 285–96. 5 Fuller TC, Fuller AA, Golden M, Rodey GE. HLA alloantibodies and the mechanism of the antiglobulin-augmented lymphocytotoxicity procedure. Hum Immunol 1997; 56: 94–105. 6 Rodey GE, Neylan JF, Whelchel JD, Revels KW, Bray RA. Epitope specificity of HLA class I alloantibodies: I, frequency analysis of antibodies to private versus public specificities in potential transplant recipients. Hum Immunol 1994; 39: 272–80. 7 Pettaway CA, Freeman CC, Helderman HJ, Stastny P. Kidney transplant recipients with long incubation-positive, antiglobulinnegative T-cell crossmatches. Transplantation 1987; 44: 529–33. 8 Talbot D, Givan AL, Shenton BK, et al. The relevance of a more sensitive crossmatch assay to renal transplantation. Transplantation 1989; 47: 552–55. 9 Kao KJ, Scornik JC, Small SJ. Enzyme-linked immunoassay for anti-HLA antibodies: an alternative to panel studies by lymphocytoxicity. Transplantation 1993; 55: 192–99. 10 Zachary AA, Ratner LE, Graziani JA, et al. Characterization of HLA class I specific antibodies by ELISA using solubilized antigen targets: II, clinical relevance. Hum Immunol 2001; 62: 236–46. 11 Pei R, Lee JH, Shih NJ, Chen M, Terasaki PI. Single human leukocyte antigen flow cytometry beads for accurate identification of human leukocyte antibody specificities. Transplantation 2003; 75: 43–49. 1576 12 13 14 15 16 17 18 19 20 21 22 23 Opelz G, Wujciak T, Döhler B, Scherer S, Mytilineos J. HLA compatibility and organ graft survival. Rev Immunogenet 1992; 1: 334–42. Collaborative Transplant Study, University of Heidelberg, Germany. Available at: www.ctstransplant.org (accessed May 15, 2004). Kaplan EL, Meier P. Nonparametric estimation from incomplete observations. J Am Stat Assoc 1958; 53: 457–81. Dunn OJ, Clark VA. Applied statistics: analysis of variance and regression. New York: John Wiley, 1974: 236. Cox DR. Regression models and life-tables. J R Stat Soc (B) 1972; 34: 187–220. Marsh SGE, Albert ED, Bodmer WF, et al. Nomenclature for factors of the HLA system. Tissue Antigens 2002; 60: 407–64. Barger CF, Shroyer TW, Hudson SL, et al. Successful renal allografts in recipients with cross-match-positive, dithioerythrioltreated negative sera. Transplantation 1989; 47: 240–44. Bryan CF, Martinez, J, Muruve N, et al. IgM antibodies identified by a DTT-ameliorated positive cross-match do not influence renal graft outcome but the strength of the IgM lymphocytotoxicity is associated with DR phenotype. Clin Transplantation 2001; 15 (suppl 6): 28–35. Gale RP, Fitchen JH, Cahan M, Opelz G, Cline MJ. Pretransplant lymphocytotoxins and bone marrow graft rejection. Lancet 1978; 1: 170–72. Simpson E, Scott D, James E, et al. Minor H antigens: genes and peptides. Eur J Immunogenet 2001; 28: 505–13. Süsal C, Opelz G. Kidney graft failure and presensitization against HLA class I and class II antigens. Transplantation 2002; 73: 1269–73. Buelow R, Chiang TR, Momteiro F, et al. Soluble HLA antigens and ELISA: a new technology for crossmatch testing. Transplantation 1995; 60: 1594–99. www.thelancet.com Vol 365 April 30, 2005 Page 231 of 290 Copyright American Journal of Transplantation 2003; 3: 665–673 Blackwell Munksgaard # Blackwell Munksgaard 2003 ISSN 1600-6135 Special Article Humoral Theory of Transplantation Paul I. Terasaki* Terasaki Foundation Laboratory, Los Angeles, CA *Corresponding author: Dr Paul I. Terasaki, [email protected] According to the humoral theory of transplantation, antibodies cause allograft rejection. Publications are cited showing that antibodies: (1) cause hyperacute kidney rejection, (2) lead to C4d deposits associated with early kidney graft failures, (3) are a good indicator of presensitization leading to early acute rejections, (4) were present in 96% of 826 patients who rejected a kidney graft, (5) are associated with chronic rejection in 33 studies of kidney, heart, lung and liver grafts, and (6) in three studies, appeared in the circulation BEFORE evidence of bronchiolitis obliterans in lung transplants, and BEFORE kidney rejection. In addition, a prospective cooperative study of 1629 patients in 24 centers demonstrated that antibodies foretold subsequent failures after a follow-up period of 6 months (p = 0.05). The specificity of antibodies detected in the serum of rejecting patients were often not donor specific, presumably because they were absorbed by the rejecting organ. If the humoral theory is accepted, even provisionally, transplanted patients who have antibodies could be treated with immunosuppression until the antibodies disappear to determine whether chronic rejection can be blocked. If successful, in patients who do not have antibodies, immunosuppression could be reduced until antibodies appear. Received 13 November 2002, revised 26 December 2002 and accepted for publication 13 February 2003 Sir Peter Medawar. Another possible reason we do not hear much of the debate today is that we now ‘KNOW’ that BOTH humoral and cellular mechanisms are involved in rejection. But is this so? Of course, antibodies are produced by cells, and in this sense all rejections are cellular. The critical difference between the two theories is: (a) are grafts destroyed by the action of antibodies or (b) by direct cellular cytotoxicity, as occurs with cytotoxic T cells, NK cells, or DTH reactions. I will review the accumulating evidence that HLA antibodies can directly cause allograft rejection in humans. This is not intended to be a ‘balanced’ review, and assumes that the reader has had sufficient exposure to the abundant literature showing that rejection is produced by cells, such as DTH reactions and tubulitis lesions produced by T cells in kidney transplants. Various current immunosuppressive treatments may have successfully suppressed cellular immunity, leaving humoral reactivity to be dealt with in the remaining patients. Gorer first showed that various antibodies in mice could be detected against the H-2 histocompatibility locus antigens (1). Based on these studies, a large-scale international effort with extensive collaboration in international workshops resulted in the discovery of antibodies to HLA antigens in humans. Thus, acceptance of the humoral theory led to uncovering the antigens against which allograft reaction is directed. Admittedly, some pursued this line of research purely as a scientific endeavor, but my work was based from the outset on the idea that the antibodies are the visible indicators of the transplantation antigens, and the means by which we can get to the root of the problem. Introduction In the 1950s, the important question of the day was, ‘are grafts rejected by antibodies (humoral theory) or by cells?’ We do not hear much about this debate today, because for the past 40 years it has almost been an accepted fact that the cellular theory is correct. This conclusion was reached by the sheer force of one man’s personality, for few would take exception to the overpowering dogma of Conflict of interest: I am a major shareholder and Chairman of One Lambda, one of the companies that sells antibody testing kits. My publications in the humoral theory predate the formation of the company by 25 years. HLA antibodies instantly kill a kidney: hyperacute rejection The awesome power of HLA antibodies became apparent with the finding that when a kidney graft is transplanted into a patient with HLA antibodies directed against antigens of the kidney, the kidney is killed immediately (2). Thus, an entire organ such as a kidney could be destroyed by antibodies within minutes. Occasionally, not often, HLA antibodies directed against B cells produce hyperacute rejection (3). The particular susceptibility of the lung to antibody-mediated hyperacute rejections is apparent 665 Page 232 of 290 Terasaki ence or absence of cytotoxic antibodies (13) (Figure 1). Patients sensitized before transplantation had lower graft survival rates than nonsensitized patients. Moreover, this effect was even more marked in patients who had previously rejected a transplant. In the intervening 30 years, many publications have reconfirmed the fact that antibodies, as a measure of presensitization, are important for kidney (14–26), heart (27–30), liver (31–34) and lung (5) transplants. from recent experiences (4,5). Hearts are also susceptible to hyperacute rejection (6). When the kidney is rejected minutes before closure of the incision, hyperacute rejection is obvious. However, we called attention to hidden hyperacute rejection when the kidney is rejected after the wound is closed, and the kidney never functions. In 1987, the primary nonfunction rate of the first cadaver grafts was 8% in 7788 first grafts, 14% in 1471 second grafts, and 20% in 224 third grafts (7). This large difference in primary nonfunction rate was almost certainly the result of hidden hyperacute rejection following sensitization by graft rejection. Today, with improved crossmatching methods, this large difference in primary nonfunction has been eliminated, and graft survival in first and regrafted patients is virtually identical (8). HLA antibodies are associated with acute early rejection For many years, antibodies were sought in biopsies taken during acute rejections, searching by immunofluorescence for IgG or IgM antibodies, generally to no avail. A major break occurred in 1993 when Feucht demonstrated that an end-product of complement C4d could be demonstrated in peri-tubular capillaries (35). Feucht showed C4d deposits in 51 of 93 dysfunctional grafts. Among patients with c4d, 1-year survival was 57% compared with 90% in those without C4d. Eight years later the same group provided convincing proof of antibodies producing early graft failures (36). They showed that presence of C4d in 117 grafts led to significantly lower graft survival than in 101 grafts without C4d (p ¼ 0.0001) (Figure 2). Antibodies to lymphoblastoid cell lines of the donor DR type were found together with C4d in 14 of 18 patients. Among those patients without antibodies, 11 of 30 had C4d (p ¼ 0.008), suggesting that C4d detection was a more sensitive indicator of antibodies than antibody detection in the circulation. The extraordinary power of antibodies is shown when high-titered HLA antibodies transfused intravenously can even kill a patient within hours. The phenomenon of transfusion-related acute lung injury (TRALI) produced by sera from highly immunized pregnant women was first described in 1970 (9), and reviewed in 1985 (10) and 2001 (11). State of preimmunization is detected by HLA antibodies When patients are immunized by the process of rejecting an allograft, the only current practical way to detect this state of immunization is by a humoral (not cellular) test: that is, examining patients for the presence of HLA antibodies. Such antibodies are found in pregnant women, patients immunized by transfusions, those immunized by rejection of a previous graft, and patients with cadaveric venous and arterial allografts (12). Proof that a humoral test for sensitization is effective was first provided by survival curves in patients classified according to the pres- 100 A flurry of recent publications by the Munich group (37,38), Boston group (39–43), Vienna group (44–47), Basel group (48) and the Vancouver group (49) has reconfirmed the association of antibody detected with C4d staining in early as well as late failure. 100 Second Tx First Tx 80 Survival (%) 80 n = 225 Without Cytotoxins 60 60 40 40 With Cytotoxins n = 72 20 Without Cytotoxins n = 19 20 With Cytotoxins n = 13 0 0 0 4 8 12 16 20 24 28 0 Time (months) 666 4 8 12 16 20 Figure 1: First demonstration that patients classified by their panel reactive antibody (PRA) as having HLA antibodies BEFORE transplantation would have lower graft survival rates than those without antibodies (13). The effect is greater in second transplants than in first grafts. It is probable that the antibodies themselves produce graft destruction early after transplantation. American Journal of Transplantation 2003; 3: 665–673 Page 233 of 290 Humoral Theory of Transplantation kidneys (17,79–83), kidney-pancreas (84), heart (30), and lungs (85,86). Cumulative Survival (%) 100 75 HLA antibodies are present after almost all kidney failures C4d– (n = 101) 50 p = 0.0001 25 C4d+ (n = 117) 0 0 4 8 12 Post-transplant (years) 16 Figure 2: Evidence that early detection of C4d in biopsies is associated with early graft failure (37). The effect of antibodies occurs in the early post-transplantation period. HLA antibodies are associated with chronic rejection Chronic rejection is currently recognized universally as the main transplantation problem. The term ‘chronic rejection’ may have become too loosely defined, and Halloran has proposed a new nomenclature (50,51). However, because this review deals with older studies for which more precise definitions cannot be substituted, we will use the term chronic rejection in the old sense, with special reference to failure resulting from immunologic rejection. HLA antibodies found AFTER transplantation were first associated with failures in 1968 (52) and 1970 (53). Antibodies to DR were shown to appear after rejection of grafts in 1978 (54), and were studied in a series of patients post-transplantation (55). In 2000, we reviewed 23 publications in which the presence of HLA antibodies was associated with acute and chronic rejection (56). There were 12 studies of antibodies in post kidney transplant patients (19,57–68). In all the studies, there was a statistically significant correlation of antibodies with acute rejection, chronic rejection, or graft survival. Similarly, there were five studies of heart transplant patients showing that patients with antibodies had lower graft survival rates than those without antibodies (59,69–72). Three studies of lung transplants (73–75), one of liver transplants (76), and two of cornea grafts (77,78) also showed that graft survival was lower in patients with antibodies than in those without antibodies. Since publication of this review, 10 further papers have been published that show the same type of association for American Journal of Transplantation 2003; 3: 665–673 If HLA antibodies cause graft failure they should be found in the serum of all patients who reject a graft. Our first studies of kidney transplant patients following graft rejection showed 54% had antibodies (52). After the identification of Class II antibodies (54), the percentage of patients with antibodies rose to 72% (55). With further improvements in sensitivity, 82% of patients rejecting a graft had antibodies (87). Following the introduction of the more sensitive flow cytometry tests, Harmer found that 95% of 100 patients studied had antibodies (88). We recently compiled the test results of 826 patients from five different transplant centers who had rejected their transplants (89). Approximately 90% of the patients tested by the AHG enhanced cytotoxicity test for antibodies had antibodies, and when those patients who did not have antibodies were retested by ELISA or flow cytometry tests, the percentage of patients with antibodies rose to approximately 96%. Thus, it is certain that almost all patients who reject a transplant have HLA antibodies. I am not aware of comparable studies in which, for example, 100 patients rejecting a graft have all been shown to have cellular immunity. Although this does not definitively prove a causal relationship for antibodies, it is a result that would be anticipated if the humoral theory is correct. It could, however, be argued that the antibodies were the result of rejection and not the cause of rejection. Evidence to the contrary is given in the next section. HLA antibodies precede kidney rejection If HLA antibodies cause chronic rejection they should be found BEFORE graft rejection. Development of HLA antibodies preceded the development of bronchiolitis obliterans in 10 of 15 patients. Among the 12 patients who did not develop HLA antibodies, none developed bronchiolitis obliterans (p < 0.001; 75). The temporal relationship strongly indicates that antibodies were responsible for development of bronchiolitis obliterans. In a study of 76 nonsensitized renal transplant recipients, among those who developed antibodies, 11 of 12 patients (92%) lost their grafts, whereas only 11% of 64 patients lost their grafts if they did not produce post-transplant antibodies (p < 0.001; 81). Thus, antibodies were predictive of chronic rejection and were found BEFORE graft failures. In a similar study of 150 renal transplant patients, 25% had antibodies, and among those who had antibodies six had graft failure 3 years later, whereas only one patient who did not have antibodies failed (p < 0.009; 90). 667 Page 234 of 290 Terasaki 0 <6 m 1y 2 3 4 7 6 5 8y Fail F F F F F F F Negative Positive F F F F F F Post-transplant antibody Figure 3: Annual tests for antibodies were carried out on 14 patients who did not have any pretransplant antibodies (91). Chronic rejection and failure after transplantation often occurred many years AFTER the appearance of antibodies. grafts may survive for long periods of time with antibodies . . . but they eventually fail. We hypothesize that antibody binds to the endothelium causing a cycle of injury and repair over many months and even years. The process of intimal vessel thickening is slow and gradual. It is critical to understand that all surveys of patients with functioning grafts show that approximately 30% of the patients already have antibodies (see section on ‘HLA antibodies are associated with chronic rejection’). This does not disprove the humoral theory, as the theory postulates that damage is gradual and all those with antibodies WILL eventually fail (Figure 3). Unfortunately, to date we are not aware of studies on the natural history of antibodies; for example, in some instances they may disappear as a result of immunosuppression and may then return. Hopefully our prospective study mentioned earlier will gather information on this issue. Antibody specificity The clearest evidence that antibodies PRECEDE rejection is provided by the studies of Lee (91) (Figure 3). Over a period of 8 years, Lee tested his patients annually for development of antibodies. In the subset of 14 patients who did not have antibodies before transplantation shown in Figure 3, antibodies appeared in all cases before the graft failure. In many instances, years had elapsed between antibody appearance and graft rejection. This suggests that injury produced by antibodies takes a variable and sometimes a considerable amount of time before its action finally manifests. In a cooperative prospective chronic rejection study involving 24 international centers, 1629 patients with functioning allografts, who did not have antibodies when they were transplanted, were examined for de novo HLA antibodies. Subsequently, approximately 6 months later, centers were asked to report on patients whose grafts had failed since the time of testing. Of 212 patients who developed antibodies, 3.3% failed compared with a 1.3% failure rate among 1417 patients who did not develop antibodies (p ¼ 0.05). If deaths were counted as a failure, 3.8% of those who developed antibodies failed compared with 1.8% of those who did not develop antibodies (p ¼ 0.05). Thus, there were significantly more failures in those who developed antibodies than in those who did not. This prospective study is ongoing to establish that the development of antibodies in patients with functioning grafts presages subsequent failure. One might ask, ‘why did not 100% of those with antibodies fail?’ The answer is that we have only followed up these patients for a 6-month period. We are aware of only one study published to date in which the follow up of patients who have antibodies has been as long as 8 years. In the publication of Lee et al. (91) cited earlier and as shown in Figure 3, patients with well-functioning 668 Until now we have referred to antibody as detected by a panel of cells or antigens. Many studies have not had available cells from the original donor. With the recent development of flow cytometry beads having single antigens prepared from recombinant cells (92), it has become possible to study the specificities present in sera. Interestingly, patients who rejected a kidney transplant had antibodies against specificities other than those to which they were immunized. This phenomenon has actually often been encountered in the past. For example, Ceppellini carefully chose donors and recipients for his planned immunization program in order to obtain monospecific typing sera. However, despite great efforts, very few ‘clean’ sera with specificity directly against the donor mismatch were produced. In addition, screening thousands of pregnancy sera was necessary to find sera that were monospecific in their reactivity. For reasons still unknown, extra specificities are often produced upon immunization. Lee et al. (91) also found that often patients who are rejecting their grafts do not have antibodies directed specifically against their donor. As such antibodies were found in sera AFTER rejection (92), we assume that DURING rejection the antibodies directed against the donor are absorbed by the graft and only the extra antibodies circulate in the peripheral blood. Thus, the strong association of antibodies with rejection in the studies of Lee et al. (91) resulted from detection of nondonor specific antibodies. The nonspecific nature of the response could be explained by the idea that antibodies are merely indicators of immune responsiveness, and that they might not be directly involved in the rejection, as would be postulated by the humoral theory. After rejection of grafts, donorspecific antibodies were found (92), making it unlikely that the antibody is simply an indicator of responsiveness. American Journal of Transplantation 2003; 3: 665–673 Page 235 of 290 Humoral Theory of Transplantation Consequences of accepting the humoral theory An important consequence of adopting the humoral theory is that we can now treat patients by reducing antibody levels and monitoring antibodies. Three patients with acute humoral rejections following live donor transplants were treated successfully by plasmapheresis and IV IgG (93). Pre-emptive plasmapheresis and IV IgG treatment of five patients with a positive flow cytometry crossmatch was also successful. Immuno-absorption of antibodies with protein A columns was effective in five of six patients with a mean PRA of 65% for a mean follow up of 54 months (94). Intravenous IgG treatment has been shown to reduce HLA antibody levels (95,96). Desensitization of patients with antibodies was effective in 13 of 15 patients treated with IV IgG (97). Although the exact mechanisms by which this occurs remains unclear (98), it assumes that antibodies are the principal agents of damage. Treatment with tacrolimus and mycophenolate mofetil was effective in four instances of chronic humoral rejection in patients 4–16 years post-transplantation (99). After treatment, the titers of donor-specific antibodies dropped dramatically and the serum creatinines stabilized. MMF was also effective in reducing titers of anti-A and -B red cell antibodies in patients who had received ABO incompatible kidneys (100). Whether or not certain drugs influence humoral immunity can be investigated. In a study of 86 cardiac transplant patients, MMF treatment resulted in less antibody formation than with azathioprine treatment (101). Treatment of acute cardiac humoral rejection with antiCD20 monoclonal antibodies directed against B cells was effective in one patient whose rejection was reversed and who remained rejection free for at least 1 year (102). Remaining issues patients who rejected kidneys, are of particular interest because they are detected on endothelial cells but not lymphocytes (109–112). Antibodies were found against epithelia, monocyte, and endothelial lines in patients rejecting allografts (113–116). Also, antibodies to endothelial cells may not necessarily be polymorphic, but rather antibodies that occur secondarily to damage (117). Hyperacute rejection as a result of antibodies to endothelial cells has been reported (118). Some antibodies may be helpful to the graft such as autoantibodies (119). When present before transplantation, antibodies against Fab have been shown to be beneficial (120), and more recently IgA anti-Fab autoantibodies have been shown to improve graft survival (108). They could possibly counteract the activity of conventional cytotoxic antibodies. Anti-idiotypic antibodies to HLA may also be counter reactive (121–123). A second histocompatibility locus A second histocompatibility locus, other than HLA, is important in transplantation. HLA identical sibling donor grafts are slowly rejected and graft vs. host reactions occur in bone marrow transplants from HLA-identical siblings. Antibodies against these minor histocompatibility loci have not yet been found. Soluble antigens The presence of soluble HLA antigens in serum may complex with HLA antibodies in serum, interfering with measurement of HLA antibodies (68 124). The presence of soluble antigens in liver transplant patients may inhibit antibody action (125). Mechanism of action Antibodies are thought to be the key triggering factor in the humoral theory, but how it produces its damage through a cascade of events remains to be clarified. Studies of the transducing activation signals in endothelial cells following adherence of HLA antibodies have been reported (126 127). HLA antibody isotypes The relative importance of Class I and Class II antibodies remains to be resolved (103). As for the antibody isotype, most of the tests were performed with IgG antibodies. In five patients transplanted across an IgM-positive crossmatch, hyperacute rejection was not found and the patients had good early function (104). Patients who had IgM-positive crossmatch by flow cytometry had slightly higher graft survival rates than those who were negative (105). IgA antibodies pretransplant were associated with higher graft survival (106–108). Immunogenic epitopes Perhaps the most interesting work still pending is the determination of immunogenic epitopes, or the actual epitopes against which the antibody response is made. These immunogenic epitopes should provide us with more accurate HLA donor/recipient organ matching than the currently utilized ‘antigens’. Non-HLA antibodies Antibodies that affect grafts may be against antigens other than HLA antigens. MICA antibodies, found in the sera of I have reviewed accumulated evidence supporting the humoral theory of transplantation. The purpose of a theory is to stimulate research proving its validity. My own work American Journal of Transplantation 2003; 3: 665–673 Conclusion 669 Page 236 of 290 Terasaki since 1959 (128) has been fueled by this hypothesis. Although antibodies can kill cells within minutes in vitro, perhaps the crucial new understanding is that antibodies may take many months or years to produce the chronic vascular endothelial thickening that ultimately chokes off the graft. The presence of antibodies in well-functioning grafts appears at first sight to prove that they are not important. Only by a longer follow up period can the significance of the antibodies be appreciated (see section on ‘HLA antibodies precede kidney rejection’). 15. 16. 17. 18. I hope this review will stimulate a parallel review of the cellular theory. 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Antibodies to endothelial cells identify myocardial damage and predict development of coronary artery disease in patients with transplanted hearts. Hum Immunol 1999; 60: 826–832. 118. Sumitran-Karuppan S, Tyden G, Reinholt F, Berg U, Moller E. Hyperacute rejections of two consecutive renal allografts and American Journal of Transplantation 2003; 3: 665–673 119. 120. 121. 122. 123. 124. 125. 126. 127. 128. early loss of the third transplant caused by non-HLA antibodies specific for endothelial cells. Transpl Immunol 1997; 5: 321–327. Terness PI, Navolan D, Dufter C, Welschof M, Opelz G. Immunosuppressive anti-immunoglobulin autoantibodies. specificity, gene structure and function in health and disease. (Noisy-legrand) Cell Mol Biol 2002; 48: 271–278. Horimi T, Chia D, Terasaki PI, Ayoub G, Iwaki Y. Association of anti-F (ab0 ) 2 antibodies with higher kidney transplant survival rates. Transplantation 1982; 33: 603–605. Mohanakumar T, Rhodes C, Mendez-Picon G, Flye MW, Lee HM. Antiidiotypic antibodies to human major histocompatibility complex class I and II antibodies in hepatic transplantation and their role in allograft survival. Transplantation 1987; 44: 54–58. Hardy MA, Suciu-Foca N, Reed E et al. Immunomodulation of kidney and heart transplants by anti-idiotypic antibodies. Ann Surg 1991; 214: 522–528. Chauhan B, Phelan DL, Marsh JW, Mohanakumar T. Characterization of antiidiotypic antibodies to donor HLA that develop after liver transplantation. Transplantation 1993; 56: 443–448. Reed EF, Hong B, Ho E, Harris PE, Weinberger J, Suciu-Foca N. Monitoring of soluble HLA alloantigens and anti-HLA antibodies identifies heart allograft recipients at risk of transplant-associated coronary artery disease. Transplantation 1996; 61: 566–572. Mathew JM, Shenoy S, Phelan D, Lowell J, Howard T, Mohanakumar T. Biochemical and immunological evaluation of donor-specific soluble HLA in the circulation of liver transplant recipients. Transplantation 1996; 62: 217–223. Bian H, Harris PE, Reed EF. Ligation of HLA class I molecules on smooth muscle cells with anti-HLA antibodies induces tyrosine phosphorylation, fibroblast growth factor receptor expression and cell proliferation. Int Immunol 1998; 10: 1315–1323. Jin Y, Du Singh RZ, Rajasekaran A, Rozengurt E, Reed E. Ligation of HLA class I molecules on endothelial cells induces phosphorylation of Src, paxillin, and focal adhesion kinase in an actin-dependent manner. J Immunol 2002; 168: 5415–5423. Terasaki PI. Antibody response to homografts II. Preliminary studies of the time of appearance of lymphoagglutins upon homografting. Am Surg 1959; 25: 896–899. 673 Page 240 of 290 Studies evaluating the association between HLA antibodies and acute and chronic kidney transplant rejection were reviewed in two recent publications: • McKenna et al., Transplantation 2000;69:319-326 • Terasaki PI. Am J Transplant 2003;3:665-673. Below are the abstracts from the 21 papers relating to kidney transplantation that were reviewed in these two papers. 1. Abe, M., T. Kawai, et al. (1997). "Postoperative production of anti-donor antibody and chronic rejection in renal transplantation." Transplantation 63(11): 1616-9. To study the relevance of anti-donor antibody (ADA) to chronic rejection in kidney transplantation, we retrospectively examined the long-term kinetics of ADA by flow cytometric analysis.. In the CR group, IgG antibody to donor B cells of the most current serum was positive in 25 of 29 patients, whereas it was positive in only 5 patients in the ST group P<0.001. We conclude that the posttransplant production of IgG antibody to donor B cells seemed to be highly relevant to chronic rejection. 2. al-Hussein, K. A., B. K. Shenton, et al. (1994). "Characterization of donor-directed antibody class in the post-transplant period using flow cytometry in renal transplantation." Transpl Int 7(3): 182-9. Over the past few years there has been increasing awareness of the importance of humoral mechanisms in the rejection of renal transplants. In this study we have monitored the development of antibodies directed against donor T and B lymphocytes using the sensitive flow cytometric technique. Forty-two cadaveric renal transplants were studied both before and for a maximum of 14 days after transplantation. Donor cells were separated from spleen on the day of transplantation and stored in liquid nitrogen until required. The dual colour flow cytometric assay was used to detect IgG or IgM directed against donor T or B lymphocytes. Using AB sera as controls, results were expressed as relative median fluorescence (RMF) and then correlated with the clinical performance of the grafts. Significant associations were found between the incidence of donordirected antibodies and the development of clinical rejection. The magnitude of the rise in antibody levels was also related to graft performance. In patients showing severe graft rejection, high levels of antibodies of the IgG class developed before the clinical diagnosis of rejection was made. The routine use of this test allows the prediction of impending severe rejection to be made and may have important implications for immunosuppressive therapy. 3. Barr, M. L., D. J. Cohen, et al. (1993). "Effect of anti-HLA antibodies on the long-term survival of heart and kidney allografts." Transplant Proc 25(1 Pt 1): 262-4. Study of anti-HLA antibodies in a population of 238 primary renal and 199 primary transplants. The 5-year renal allograft survival was 70% in recipients without antibodies and 53% in recipients who developed anti-HLA alloantibodies during the first year following transplantation. Development of antibodies is associated with acute rejection episodes and probably with the release of soluble HLA antigens. Page 241 of 290 4. Christiaans MH, Overhof-de Roos R, Nieman F, van Hooff JP, van den Berg-Loonen EM. Donor-specific antibodies after transplantation by flow cytometry: relative change in fluorescence ratio most sensitive risk factor for graft survival. Transplantation 1998; 65 (3):427 BACKGROUND: There is no consensus on the role of donor-directed antibodies after renal transplantation detected by complement-dependent cytotoxicity (CDC) or by flow cytometry (FC).METHODS: Therefore, antibody formation was studied by FC and correlated with clinical course in a group of patients who received transplants between 1983 and 1993. All had a negative current CDC crossmatch and were treated with cyclosporine. Current and posttransplant sera from 143 donor-recipient combinations were studied retrospectively. Antibodies were considered present in FC if the fluorescence ratio between serum and negative control was > 2.65. RESULTS: Of 143 patients, 17 (11.9%) were found to be positive in the posttransplant FC crossmatch and 126 (88.1%) were negative. Of the positive patients, 3 were already positive in the current FC crossmatch, whereas 14 demonstrated a positive posttransplant FC crossmatch after a negative current FC crossmatch. It was noteworthy that, from 16 patients with a positive current FC crossmatch, 13 turned negative in the posttransplant crossmatch. In 113 recipients (79%), both pre- and posttransplant FC crossmatches were negative. The development of a positive FC crossmatch after transplantation was a significant risk factor for graft survival in Cox regression analysis (P = 0.01). The results were also studied as relative change in fluorescence ratio (RCFR). RCFR was determined by classifying the recipients in quartiles according to their change in flow cytometric value from current to posttransplant serum. Quartiles were defined as follows: quartile 1, decrease > 10%; quartile 2, decrease 0-10%; quartile 3, increase > 0-30%; and quartile 4, increase > 30%. RCFR proved to be the only significant risk factor for graft survival (odds ratio for quartile 4 vs. quartile 1, 3.27; P < 0.02). More rejections were shown for increasing quartile numbers (P < 0.001). CONCLUSIONS: Classification of patients by RCFR detected more patients with unfavorable clinical outcome (25% vs. 11%) than by FC crossmatch. 5. El Fettouh, H. A., D. J. Cook, et al. (2000). "Association between a positive flow cytometry crossmatch and the development of chronic rejection in primary renal transplantation." Urology 56(3): 369-72. This study examined the effect of kidney transplantation against a positive flow cytometry crossmatch (FCXM) on the subsequent development of chronic rejection and graft failure.. All of these patients had a negative cytotoxicity crossmatch. All had a pretransplant FCXM, and patients were divided according to the results of the FCXM into three categories: FCXM negative, FCXM class I positive, and FCXM class II positive. RESULTS: We found that a positive FCXM at the time of transplantation was strongly associated with the ultimate development of chronic rejection. In FCXM-negative individuals, 16.9% developed chronic rejection compared with 80% of those with an HLA class I (T and B-cell) reaction and 40.9% of those with a class II (B-cell-only) reaction (P <0.001). The 3-year graft survival rate was 93% for FCXM-negative patients compared with 86% for FCXM class II positive and 80% for FCXM class I positive Page 242 of 290 patients (P = 0.001). CONCLUSIONS: A strong association between a positive FCXM and subsequent development of chronic rejection was identified. 6. Halloran, P. F., J. Schlaut, et al. (1992). "The significance of the anti-class I response. II. Clinical and pathologic features of renal transplants with anti-class I-like antibody." Transplantation 53(3): 550-5. Although the ability of preformed anti-class I antibodies to mediate hyperacute rejection is well established, their pathogenic role in acute rejection remains illdefined. We set out to identify patients with anti-class I against donor cells and to define the clinical and pathological features of such patients. We collected sera pretransplant and in the first 3 months posttransplant from 64 renal transplant recipients (59 cadaver donors and 5 one-haplotype matched living-related donors). We assayed the sera for class I-like antibody against donor T cells in complement-dependent microcytotoxicity, with crossmatches against autologous T cells to exclude auto-antibodies. All pretransplant sera were negative against donor T cells. Of the 797 sera tested posttransplant, 131/195 sera from 13 patients were positive, and 602 sera from 51 patients were negative. All patients who formed anti-class I underwent rejections compared with only 41% of patients with no anti-class I detected (P less than 0.0005). More rejections in patients with anti-class I were classed as severe (12/15 [80%] compared with 9/28 [32%] P less than 0.005), and graft loss was significantly higher (5/13 vs. 2/51; P less than 0.002). Rejections associated with anti-class I occurred earlier; more frequently developed oliguria (35% versus 10%) and required dialysis (40% versus 10%) and biopsies (10/13 vs. 6/28); and had a higher rate of rise in serum creatinine (249 versus 79 microns/L in the first 48 hr). Biopsies during anti-class I positive rejections more frequently displayed endothelial injury in the microcirculation, neutrophils in the glomeruli and/or peritubular capillaries, and fibrin deposition in glomeruli or blood vessels. The biopsies in anti-class I negative rejection episodes tended to have tubulitis, interstitial infiltration, and blasts, suggesting that these lesions reflect T-cell-mediated mechanisms. We conclude that patients with antibody against donor class I had more severe rejection, probably because anti-class I injuries the endothelium of small blood vessels of the graft, leading to rapid functional deterioration. We believe that anticlass I may be a major factor in some severe rejection episodes 7. Kerman RH, Susskind B, Kerman DH, et al. Anti-HLA antibodies detected in posttransplant renal allograft recipient sera correlate with chronic rejection. Transplant Proc 1997; 29 (1–2):1515. Chronic rejection is an important cause of graft loss after the first posttransplant year. Both antigendependent (immune injury) and alloantigen-independent events contribute to chronic graft dysfunction. Our study focuses on the antigendependent, immune-injury aspects of chronic rejection. Of the several hypotheses explaining the immune basis of chronic rejection, antibody-mediated graft damage may predominate. A reliable postoperative monitor of serologic alloimmunity could identify high-risk patients experiencing rejections and rejection-related morbidity. Most studies attempting to correlate percent panel reactive antibodies (% PRA) and specific antidonor reactivity with clinical events Page 243 of 290 utilized a complement-dependent cytotoxicity (CDC) assay. Because of the inherent problems related to CDC-PRA assays, the test has been variably reliable. An ELISA procedure to detect IgG anti-HLA class I antibodies has recently been reported that determines anti-HLA % PRA and specificity as well. In the present study we tested pre- and posttransplant sera from renal allograft recipients for anti-HLA alloimmunity by antihuman globulin (AHG) and ELISA methodologies, and correlated AHG-PRA and/or ELISA-PRA to rejection. The data suggest that ELISA-PRA, but not AHG-% PRA,identified recipients at risk for adverse immunologic and clinical events. 8. Kerman, R. H., S. M. Katz, et al. (2001). "Posttransplant immune monitoring of antiHLA antibody." Transplant Proc 33(1-2): 402 Although the presence of anti-HLA antibodies in renal transplant recipient sera has been associated with graft rejection and decreased graft survivals, the role of these antibodies is not well-understood.[1] A reliable test that monitors serologic anti-HLA reactivity might identify patients at risk for rejection or graft loss. [2] We used an enzyme–linked immunosorbent assay (ELISA) to detect IgG anti–HLA class I and class II antibodies bound to a matrix of soluble HLA antigens (PRASTAT). Sera were collected pre– and serially–posttransplantation for 19 ± 8 months from 123 cyclosporine (CsA)-Prednisone (Pred) treated primary recipients of a cadaveric donor renal allograft. Sera were collected monthly or every other month with an average of 15 sera per patients tested. Patients were transplanted with ABO compatible donor organs following a negative anti-human globulin (AHG) enhanced complement dependent cytotoxicity crossmatch. No patient experienced hyperacute or accelerated rejection. One third of the patients (41 of 123) presented with a pretransplantation IgG anti-HLA PRA ≥ 10% with 67% of the antibody directed against MHC class I and 33% against MHC class I and II. The rejection frequency of 73% for patients with pretransplantation IgG anti-HLA PRA ≥ 10% was significantly greater than the 27% for patients with a pretransplantation PRA < 10% (73% vs 27%, P < .01). Postoperatively, one-third of the patients did not develop ELISA-detected anti-HLA antibodies, had a 10% frequency of rejections, had a 90% one-year graft survival, and had only an 8% frequency of chronic rejection. In contrast, the 67% of the patients with ELISAdetectable IgG anti-HLA PRA ≥ 10% experienced a 55% rejection frequency (10% vs 55%, P < .001), a 79% 1-year graft survival (90% vs 79%, P < .02), and a 26% frequency of chronic rejection from one to three years posttransplantation (8% vs 26%, P < .02). Antibody specificities were directed at both donor and nondonor HLA antigens. Two-thirds of the antibodies were against MHC class I and one third against MHC class I and II antigens. There was a significantly consistent monthly ELISA-detected IgG anti-HLA PRA ≥ 10% present in sera 3 ± 4 months prior to the diagnosis of chronic rejection but not present for nonchronic rejectors (71% vs 18%, P < .02). Our data suggest that patients with pretransplantation IgG anti-HLA antibody reactivity are at risk to (1) display posttransplantation anti-HLA antibody (including donor specific reactivity) and (2) experience early and/or chronic rejection. Patients developing posttransplantation detectable IgG anti-HLA antibody are at risk for chronic rejection. Patients without posttransplantation anti-HLA antibody could represent successfully immunoregulated recipients. Page 244 of 290 9. Kerman, R. H., C. G. Orosz, et al. (1997). "Clinical relevance of anti-HLA antibodies pre and post transplant." Am J Med Sci 313(5): 275-8. Pretransplant histocompatibility testing seeks to select compatible donorrecipient pairs for transplantation. Sera from prospective renal transplant recipients are screened for the presence of human leukocyte antigen (HLA) antibodies to determine humoral alloimmunization. Present techniques screen patient sera using a complement-dependent cytotoxicity assay and express the results as percent of panel reactive antibody (PRA). However, the standard assay suffers because it needs viable target cells, a variable sensitivity of cells for complement, subjective evaluation, a lack of standardized methodology, and a variable correlation with clinical outcomes. Alternatively, an enzyme-linked immunosorbent assay (ELISA) methodology can detect IgG anti-HLA reactivity based on the binding of immunoglobulin to soluble HLA class I antigens. This method provides increased objectivity and reproducibility, does not require use of viable target cells, and most importantly, detects immunoglobulin that is reactive to HLA class I antigens. Data discussed herein suggest that identifying reactive recipient sera using the enzyme-linked immunosorbent assay (ELISA) (PRASTAT, Sang Stat Med, Menlo Park, CA) methodology may be more informative clinically than current standard percent of panel reactive antibody (PRA) assays. 10. Martin, S., P. A. Dyer, et al. (1987). "Posttransplant antidonor lymphocytotoxic antibody production in relation to graft outcome." Transplantation 44(1): 50-3. Serial serum samples from 266 recipients of primary renal allografts were monitored posttransplant for the presence of panel reactive lymphocytotoxic antibodies (PRA). The minimum posttransplant follow-up period was 18 months. Patients were classified according to whether or not they produced PRA before and/or after transplantation. The groups were as follows: PRA negative before and after transplant, -/-, 171; PRA positive before and negative after transplant, +/-, 5; PRA positive before and positive after transplant, +/+, 27; PRA negative before and positive after transplant, -/+, 63. Actuarial graft survival at 1 year for each group was 81.3%, 100%, 70.4%, 47.6%, respectively. Fifty-five of the 63 -/+ recipients were retrospectively crossmatched with posttransplant sera against stored donor lymphocytes. Of these, 50 (91%) were posttransplant cross match positive, and 37 (67%) have lost their grafts. In 23 of the 26 cases where an antiHLA specificity was defined, the antibody was directed against antigens present in the donor but not in the recipient. These results clearly indicate that the production of PRA in recipients of renal transplants is associated with antidonor reactivity and poor graft outcome. The fact that these PRA were often directed against donor HLA antigens emphasizes one of the hazards of mismatching for HLA at transplantation. 11. Monteiro, F., R. Buelow, et al. (1997). "Identification of patients at high risk of graft loss by pre- and posttransplant monitoring of anti-HLA class I IgG antibodies by enzyme-linked immunosorbent assay." Transplantation 63(4): 542-6. Page 245 of 290 Identification of risk factors influencing graft survival may lead to the development of models to predict graft outcome. Such models may provide guidance for immunosuppressive therapy, measure posttransplantation outcome, and eventually improve graft survival in high-risk patients. A major risk factor influencing graft survival is allosensitization. However, due to the lack of standardization of lymphocytotoxicity assays, the detection of alloantibodies utilizing this current methodology may not correlate with posttransplant events. Recently, a novel standardized enzyme-linked immunosorbent assay (ELISA) for the detection of anti-HLA class I IgG antibodies was developed. To evaluate the predictive value of this diagnostic test, a retrospective analysis of 124 renal allograft recipients with an 18-month follow-up time was performed. A highly significant (P=0.01) correlation between pre-transplant ELISA panel reactive antibody (PRA) results and graft loss was observed. Patients with pre-transplant ELISA PRA of >10% had a three times higher risk of graft loss compared with patients who tested negative. No such correlation was observed with complement-dependent cytotoxicity results independent of the reduction of IgM antibodies with dithiothreitol. Similarly, a highly significant correlation of ELISA results with the occurrence of early graft dysfunction was observed. Almost all patients (88%) with a pretransplant ELISA PRA of >50% required posttransplant dialysis, compared with 45% of patients with a pretransplant ELISA PRA of 1050% and 27% of patients with a pretransplant ELISA PRA of <10%. No such difference was observed with complement-dependent cytotoxicity %PRA values. Analysis of posttransplant specimens by ELISA demonstrated a strong correlation of assay results with graft rejection and graft dysfunction. In summary, these results suggest that detection of anti-HLA class I antibodies by ELISA identifies patients at high risk for graft loss. No other single risk factor of such magnitude has been identified so far. 12. Monteiro, F., C. Mineiro, et al. (1997). "Pretransplant and posttransplant monitoring of anti-HLA class I IgG1 antibodies by ELISA identifies patients at high risk of graft loss." Transplant Proc 29(1-2): 1433-4 NO abstract available – see full article http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VJ0-3VN9BV8SN&_user=1525358&_coverDate=03%2F31%2F1997&_rdoc=1&_fmt=high&_ori g=search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000053540& _version=1&_urlVersion=0&_userid=1525358&md5=17b5094f2b3dd994e57bcf1 ca8bafff9&searchtype=a 13. Muller-Steinhardt, M., L. Fricke, et al. (2000). "Monitoring of anti-HLA class I and II antibodies by flow cytometry in patients after first cadaveric kidney transplantation." Clin Transplant 14(1): 85-9. While the relevance of pre-formed anti-human leukocyte antigen (HLA) antibodies has been studied extensively, the role of anti-HLA class I and II antibodies produced after cadaveric kidney transplantation is still a matter of discussion. As it has been proposed that they are involved in a considerable number of cases, it should be investigated whether a post-transplant monitoring is a sensitive parameter for the early diagnosis of acute rejection episodes. Page 246 of 290 Additionally, it has been suggested that antibodies are a major cause for chronic rejection; thus, it would be of interest to correlate antibody detection and graft survival. We retrospectively investigated 59 patients after a first cadaveric kidney transplantation without known anti-HLA antibodies (complement-dependent cytotoxicity [CDC] testing). The panel reactivity was determined with a new highly sensitive and specific flow-cytometric technique (Flow-PRA Screening Test, One Lambda, Canoga Park, USA) in sequentially collected serum samples pre- and post-transplant. In patients with acute rejection episodes during the clinical course, the last sample prior to rejection, and in patients without rejection, the last sample prior to discharge, was analyzed. Furthermore, we analyzed 3-yr graft survival and several clinical parameters such as cold ischemia time (CIT). Twenty-four of 59 patients (41%) experienced acute rejections during the clinical course. Five of 59 died with a functioning graft within the first 3 yr. Seven of 54 patients, still alive after 3 yr, lost their graft. Anti-HLA antibodies were detectable in only 7/59 patients and a correlation between antibody positivity and acute rejections (p = 0.32 and 0.54 for anti-HLA class I and II, respectively) could not be identified (sensitivity 12.5 and 8.3%). However, we found a significant correlation between the detection of anti-HLA class II and graft loss within 3 yr (p = 0.005, specificity 97.9%). Additionally, anti-HLA class II positive patients had significantly longer CIT (p = 0.003). Whether the detection of anti-HLA class II antibodies in the early post-transplant phase is of great value for the identification of patients at high risk for early graft loss needs additional investigation. However, we found that anti-HLA antibodies are detectable only in a minority of unsensitized patients and we conclude that flow-cytometric monitoring with Flow PRA is not a sensitive parameter for the early diagnosis of acute rejection episodes in patients after first cadaveric kidney transplantation. 14. Pelletier, R. P., P. K. Hennessy, et al. (2002). "Clinical significance of MHC-reactive alloantibodies that develop after kidney or kidney-pancreas transplantation." Am J Transplant 2(2): 134-41. The purpose of this study was to determine the relationships between acute rejection, anti-major histocompatibility complex (MHC) class I and/or class IIreactive alloantibody production, and chronic rejection of renal allografts following kidney or simultaneous kidney-pancreas transplantation. Sera from 277 recipients were obtained pretransplant and between 1 month and 9.5 years posttransplant (mean 2.6years). The presence of anti-MHC class I and class II alloantibodies was determined by flow cytometry using beads coated with purified MHC molecules. Eighteen percent of recipients had MHC-reactive alloantibodies detected only after transplantation by this method. The majority of these patients produced alloantibodies directed at MHC class II only (68%). The incidence of anti-MHC class II, but not anti-MHC class I, alloantibodies detected post-transplant increased as the number of previous acute rejection episodes increased (p = 0.03). Multivariate analysis demonstrated that detection of MHC class II-reactive, but not MHC class I-reactive, alloantibodies post-transplant was a significant risk factor for chronic allograft rejection, independent of acute allograft rejection. We conclude that post-transplant detectable MHC class IIreactive alloantibodies and previous acute rejection episodes are independent risk factors for chronic allograft rejection. Implementing new therapeutic strategies to curtail post-transplant alloantibody production, and avoidance of Page 247 of 290 acute rejection episodes, may improve long-term graft survival by reducing the incidence of chronic allograft rejection. 15. Piazza, A., D. Adorno, et al. (1998). "Flow cytometry crossmatch: a sensitive technique for assessment of acute rejection in renal transplantation." Transplant Proc 30(5): 1769-71 No abstract available – see attached http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VJ0-3Y51H4H22&_user=1525358&_coverDate=08%2F31%2F1998&_rdoc=1&_fmt=high&_orig =search&_origin=search&_sort=d&_docanchor=&view=c&_acct=C000053540&_ version=1&_urlVersion=0&_userid=1525358&md5=49e716dcf17e36e1b2870b30 39ceebf1&searchtype=a 16. Piazza, A., L. Borrelli, et al. (2000). "Posttransplant donor-specific antibody characterization and kidney graft survival." Transpl Int 13 Suppl 1: S439-43. This study was designed to investigate the clinical relevance of donor-specific antibodies (DS-Abs) and their influence on graft survival. Among 106 patients who underwent cadaveric kidney donor transplantation and were monitored by flow cytometry crossmatch (FCXM) during the 1st posttransplantation year, 25 (23.6%) resulted positive for DS-Ab production. During a 2-year follow up only 12 of the 81 FCXM-negative patients (14.8%) suffered rejection vs 17 of 25 FCXMpositive patients (68%; P = 0.00001). Correlating graft loss to DS-Ab production, 9 FCXM-positive patients lost the graft vs only 1 among the FCXM-negative patients. A worse graft function was evidenced in FCXM-positive subjects who had also suffered rejection episodes than in those which had acute rejection but did not produce DS-Abs. A high incidence of HLA-AB mismatches was found in FCXM-positive subjects which produced anti-class I antibodies. FCXM appears useful in estimating posttransplant alloimmune response. Moreover our findings confirm the harmful effects of anti-class I DS-Abs on long-term graft survival. 17. Piazza, A., E. Poggi, et al. (2001). "Impact of donor-specific antibodies on chronic rejection occurrence and graft loss in renal transplantation: posttransplant analysis using flow cytometric techniques." Transplantation 71(8): 1106-12. BACKGROUND: Improvements in immunosuppressive therapy have greatly reduced acute rejection (ARj) episodes, ensuring better short-term graft outcome, but have not modified long-term survival in renal transplantation. It is now well accepted that chronic rejection (CRj) can be determined by both immune and/or nonimmune mechanisms. The aim of this study was to evaluate the importance of the posttransplant humoral immune response towards mismatched HLA graft antigens in CRj occurrence and graft outcome. METHODS: Serum samples from 120 nonpresensitized renal transplant recipients were prospectively screened for 1 year after surgery by means of flow cytometry cross-match (FCXM) and FlowPRA beads (microbeads coated with purified HLA class I and class II antigens) assays. All transplants were followed-up for 2 years or until graft removal. RESULTS: FCXM monitoring identified donor-specific antibodies (DSAbs) in 29 (24.2%) of 120 transplanted patients. Correlation with clinical data highlighted a higher incidence of ARj in DS-Abs-positive patients compared to Page 248 of 290 negative patients (62% vs. 13%, P<0.00001). Furthermore, graft failure occurred more frequently among FCXM-positive patients than among negative patients (34% vs. 1%, P<0.00001). The deleterious effect of DS-Abs on graft function was confirmed by serum creatinine levels 2 years after transplantation. These were in fact higher in subjects producing DS-Abs than in subjects with only ARj (mean creatinine: 2.5+/-1.3 mg/dL vs.1.7+/-0.5 mg/dL, P=0.04). FlowPRA analysis of DS-Ab HLA specificity highlighted the presence of anti-HLA class I antibodies in 85% of FCXM-positive patients, who also presented with a higher incidence of HLA-B mismatches than FCXM-negative patients (1.23+/-0.66 vs. 0.92+/-0.59, P=0.02). CONCLUSIONS: Flow cytometric techniques are precious tools for investigating the activation of the humoral response against HLA antigens of the graft in renal transplantation. DS-Abs production has a worse impact on organ function and survival than ARj episodes. These findings represent further proof of the threat posed by DS-Abs on long-term graft function and draw attention to the need for a specific immunosuppressive therapy aimed at counteracting the different kinds of immune activation toward graft. 18. Schonemann, C., J. Groth, et al. (1998). "HLA class I and class II antibodies: monitoring before and after kidney transplantation and their clinical relevance." Transplantation 65(11): 1519-23. BACKGROUND: In search of an alternative screening technique, we compared complement-dependent cytotoxicity (CDC) with PRA-STAT, a commercially available enzyme-linked immunosorbent assay (ELISA). METHODS: A total of 188 pre- and posttransplant sera from 50 renal allograft recipients were tested with both methods. RESULTS: A significant correlation was found between both methods. Discrepant results could be explained by the fact that PRA-STAT detects both HLA class I and II antibodies (while CDC with peripheral blood lymphocytes as target cell detects mainly HLA class I reactivity), by the presence of IgM antibodies (which are not detected by the IgG-specific ELISA test), and by CDC "false-positive" results due to antibody rejection treatment. The clinical relevance of antibodies detected by PRA-STAT is suggested by the following. (a) In eight patients, donor-specific HLA antibodies detected by PRA-STAT (but not seen by CDC) resulted in severe rejection episodes, which led to graft loss in four cases. In all but one patient, antibodies were directed against class II or mixtures of class I and H antigens. Six patients with complications were shown to have developed de novo antibodies against DQ incompatibilities. (b) Half of the patients with a positive ELISA test at the moment of crossmatch experienced complications. Such patients are at a threefold higher risk of suffering from rejection episodes and/or graft loss than patients who are not sensitized (P<0.05, Fisher exact test). CONCLUSIONS: Because PRA-STAT is very reproducible, detects both HLA class I and II antibodies, and is not influenced by rejection therapy, we consider it an additional tool for pre- and posttransplant monitoring of kidney allograft recipients. 19. Scornik, J. C., D. R. Salomon, et al. (1989). "Posttransplant antidonor antibodies and graft rejection. Evaluation by two-color flow cytometry." Transplantation 47(2): 28790. Page 249 of 290 The posttransplant production of antibodies against cryopreserved donor cells was studied in 50 consecutive cadaveric kidney graft recipients and in 23 additional patients selected for acute rejection. Serum was obtained twice weekly during the first 3 weeks posttransplant and then monthly for 6 months. IgM and IgG anti-T cell Abs were measured by 2-color flow cytometry. Results were analyzed in conjunction with the patients' demographics, previous sensitization, HLA-matching, posttransplant blood transfusions, incidence of delayed function, rejection episodes, and biopsy results. Antidonor antibodies, predominantly IgG, were detected in 19/48 (40%) of the patients proximate to the time of rejection. In contrast, antibodies were seen in only 2/22 (9%) of nonrejecting patients, and these antibodies were exclusively IgM. Younger patients were more likely to have antibody-mediated rejections. Cytotoxic antibody reactivity against panel cells developed or increased posttransplant in some patients, but it did not correlate with rejection. Previous sensitization and posttransplant transfusions favored the development of posttransplant panel reactivity but not of antidonor antibodies. Most rejections, including those associated with antidonor antibodies, were reversed by antirejection therapy. We conclude that antidonor antibodies are involved in a significant proportion of rejection episodes and that the damage induced does not necessarily culminate with loss of the graft. 20. Suciu-Foca, N., E. Reed, et al. (1991). "Soluble HLA antigens, anti-HLA antibodies, and antiidiotypic antibodies in the circulation of renal transplant recipients." Transplantation 51(3): 593-601. Chronic rejection represents the major threat to long-term survival of organ allografts. It is presumed that this form of rejection is mediated by antibodies against mismatched HLA antigens of the graft. The presence and specificity of anti-HLA-antibodies in posttransplantation sera are, however, difficult to document. We have explored the possibility that anti-HLA antibodies form immune complexes with soluble HLA antigens released from the injured graft and/or that they are blocked by antiidiotypic, anti-anti-HLA-antibodies. Our data demonstrate that the long-term survival of renal allografts is significantly lower in patients who develop anti-HLA-antibodies following transplantation than in patients who do not form antibodies. Following depletion of soluble HLA antigens by magnetic immunoaffinity, we could identify anti-HLA-antibodies in 57% of the sera obtained from patients undergoing chronic rejection of kidney allografts, compared with 41% prior to antigen depletion. In patients tolerating the graft for 4 years or more, the corresponding frequencies of antibody-positive sera was 2% and 5% prior and following depletion of HLA antigens. The presence of HLA antigen/anti-HLA-antibody immune complexes in patients' sera was positively associated with chronic humoral rejection (P less than 0.0001). Patients who tolerated the graft in spite of having developed antibodies against one of its mismatched HLA antigens show specific antiidiotypic (anti-anti-HLA-antibodies). Such antiidiotypic antibodies were not found in sera from patients with chronic rejection (P = 0.005). This indicates that antiidiotypic antibodies may delay the progression of chronic humoral rejection. Page 250 of 290 21. Trpkov, K., P. Campbell, et al. (1996). "Pathologic features of acute renal allograft rejection associated with donor-specific antibody, Analysis using the Banff grading schema." Transplantation 61(11): 1586-92. Alloantibody frequently appears during the immune response to alloantigens in renal transplant recipients. We studied whether the presence of antibody against donor class I antigens correlated with the clinical and pathologic features of acute rejection episodes. We identified patients who had (1) clinical evidence of acute rejection, (2) a renal biopsy showing pathologic features of acute rejection, defined by the Banff criteria, and (3) pre- and posttransplant sera screened against donor T cells. We divided these patients into those with or without donorspecific alloantibody reactive with donor T cells. Of 44 patients with biopsyproven rejection, 20 were antibody negative (Ab-R) and 24 were antibody positive (Ab+R). The biopsies from Ab+R patients had a higher incidence of severe vasculitis (P=0.0009) and glomerulitis (P=0.01). Fibrin thrombi in the glomeruli and/or vessels, fibrinoid necrosis, and dilatation of peritubular capillaries were also more frequent in the Ab+R group. Infarction was present in biopsy specimens from 9/24 Ab+R patients versus none in the Ab-R group (P=0.002). The Ab+R biopsy specimens more often had polymorphonuclear leukocytes in the peritubular capillaries (P=0.003). In contrast, specimens of AbR patients showed tubulitis more often than the specimens of Ab+R patients: moderate and severe tubulitis was present in 19/20 (95%) Ab-R patients versus 12/24 (50%) Ab+R patients (P=0.002). Graft loss was increased in Ab+R patients, particularly in the first 3 months (12/24 compared with 3/20, P=0.025). Thus, during biopsy-proven acute rejection episodes, anti-class I antibody correlates with severe vascular lesions, glomerulitis, and infarction, whereas more severe tubulitis predominates in rejection episodes without antibody. Appendix C - Independent Review of the Clinical Literature Appendix C - Independent Review of the Clinical Literature Page 251 of 290 Page Page 252 of 290 Literature Review: The Impact of Transfusion on Transplantation December 20, 2010 Prepared by: HERON Evidence Development LLC Page 253 of 290 Literature Review: The Impact of Transfusion on Transplantation For further details regarding this document please contact: Amgen HERON Evidence Development LLC One Amgen Center Drive 50 Division Street, Suite 503 Thousand Oaks, CA 91320-1799 Somerville, NJ 08776 USA USA TEL: +1 805 447 1000 TEL: +1 908 864 6281 Confidential. For internal use only. 2 Page 254 of 290 Literature Review: The Impact of Transfusion on Transplantation AABB ASH Acc AM AMR AR AST AVR CDC CI CKD CMS CMV CRDAC DSA DSG DST ELISA ESRD ET FK HHS HLA HSP IgG IgM IvIG ITT LAR mPTF MedCAC MMF MP NBG NKF LAR OPTN PRA PRTR PTA PTF rPTF RBC RR SEM SRTS TRIPS TRTR TTVS UNOS USRDS Abbreviations American Association of Blood Banks American Society of Hematology Accelerated Rejection Acceptably Mismatched Antibody Mediated Rejection Acute Rejection American Society of Transplant Acute Vascular Rejection Complement Dependent Cytotoxicity Confidence Interval Chronic Kidney Disease Centers for Medicare and Medicaid Services Cytomegalovirus Cardio Renal Drugs Advisory Committee Donor Specific Antibody Deoxyspergualin Donor-Specific Blood Transfusion Enzyme-Linked Immunosorbent Assay End Stage Renal Disease Eurotransplant FK-506 (Tacrolimus) Health and Human Services Human Leukocyte Antigen Highly Sensitized Patient Immunoglobulin G Immunoglobulin M Intravenous Immune Globulin Intention to Treat Late Acute Rejection Matched Pre-Transplant Blood Transfusion Medicare Evidence Development and Coverage Advisory Committee Mycophenolate Mofetil Methylprednisolone Normalized Background (ratio) National Kidney Foundation Late Acute Rejection Organ Procurement and Transplantation Network Panel Reactive Antibody Primary Renal Transplant Recipient Post Transplant Anemia Pre-Transplant Blood Transfusion Random Pre-Transplant Blood Transfusion Red Blood Cell Relative Risk Standard Error of the Mean Scientific Registry of Transplant Recipients Transfusion-Related Infections Prospective Study Third Renal Transplant Recipients Transfusion-Transmitted Viruses Study United Network for Organ Sharing United States Renal Data System Confidential. For internal use only. 3 Page 255 of 290 Literature Review: The Impact of Transfusion on Transplantation Table of Contents Project Objectives................................................................................. 7 Project Methodology ............................................................................. 7 1 The relationship between transfusions and panel reactive antibodies...................................................................................... 8 1.1 Summary ............................................................................................................... 8 1.2 Overview of panel reactive antibodies ...................................................................... 8 1.3 Evidence of the correlation between transfusions and antibody development ............... 9 2 The impact of PRAs on renal transplant matching and wait times ................................................................................... 12 2.1 Summary ............................................................................................................. 12 2.2 Overview of the correlation between PRAs, HLA cross-matching and difficulties in renal transplantation ..................................................................................................... 12 2.3 Evidence of the correlation between PRAs and wait times in renal transplantation ...... 13 3 The impact of elevated PRA levels and wait times on renal transplant success ....................................................................... 15 3.1 3.2 3.3 3.4 3.5 4 The evidence supporting strategies to mitigate the risk of graft failure .......................................................................................... 24 4.1 4.2 4.3 4.4 5 Summary ............................................................................................................. 24 Leukoreduction of the blood supply and impact on allosensitization........................... 24 Desensitization protocols and experimental induction therapy agents ........................ 25 Variance in post-transplant immunosuppressant protocols and associated costs ......... 26 Key Evidence Gaps ...................................................................... 28 5.1 5.2 5.3 5.4 5.5 5.6 5.7 6 Summary ............................................................................................................. 15 Overview of PRA levels.......................................................................................... 15 Elevated PRA levels and increases in wait time correlate to pre-transplant mortality ... 15 Evidence of elevated PRAs impacting graft survival and post-transplant complications 16 Evidence of blood transfusions impacting graft survival ............................................ 19 Inconsistent definition of highly sensitized patient ................................................... 28 Impact of timing of PRA assays on PRA levels ......................................................... 28 Reporting of exact number of prior transfusions ...................................................... 28 Under-reporting of true sensitization rates .............................................................. 28 Limited data set for post-transplant outcomes in highly sensitized patients ................ 28 Relevance of antibodies detected on newer HLA assays ........................................... 29 Reports of the positive impact of acceptable mismatch programs on graft survival outcomes in the US .............................................................................................. 29 Discussion ................................................................................... 30 References .......................................................................................... 31 Appendix A Detailed Search Strategy .............................................. 34 Confidential. For internal use only. 4 Page 256 of 290 Literature Review: The Impact of Transfusion on Transplantation List of Tables Table Table Table Table Table Table Table Table Table Table 1: Percentage of sensitizing events in each PRA category ................................................ 9 2: Risk factors for transfusion-associated allosensitization .............................................. 10 3: PRA levels in correlation to waiting times.................................................................. 13 4: 10-year graft survival by PRA level, HLA-identical sibling transplants ........................... 18 5: Acute AMR incidence as reported in six separate studies ............................................ 25 6: Immunosuppressive regimens, 1990-2007 (Toki 2009) .............................................. 26 7: Search filters for transfusion.................................................................................... 34 8: String for transplantation ........................................................................................ 34 9: String for antigens and histocompatibility ................................................................. 35 10: String for organ restriction .................................................................................... 35 Confidential. For internal use only. 5 Page 257 of 290 Literature Review: The Impact of Transfusion on Transplantation List of Figures Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 1: 2: 3: 4: 5: 6: 7: Sensitization and transfusions in first transplant patients, 1995-2000 ......................... 10 Share of transplants performed by PRA status ......................................................... 13 Median transplantation wait time by transfusion status ............................................. 14 Observed and projected median wait times by year of listing and PRA ....................... 14 3-year outcomes of first-time waitlisted patients in 2005 by PRA level........................ 16 Unadjusted graft survival for living and deceased donor transplants, by PRA .............. 17 10-year graft survival according to pre-transplant PRA, cadaver kidney and HLA-identical sibling transplants ............................................................................ 18 8: Post-transplant complications in highly-sensitized TRTR vs. PRTR patients ................. 19 9: Effect of transfusions on graft survival in non-sensitized (PRA<10%) and sensitized patients ............................................................................................................... 20 10: Acute rejection rate within 3 months of transplantation in recipients of a pre-transplant transfusion (rPTF) vs. controls (p < 0.05) .............................................................. 20 11: Death-censored 10-year graft survival in recipients of a kidney from a deceased donor: rPTF versus no rPTF (p=0.77) ............................................................................... 21 12: Death-censored 8-year graft survival in recipients of a kidney from a living donor: mPTF versus DST versus no PTF group (p=0.96) .................................................... 21 13: Graft survival after living renal allograft transplantation in patients with and without DST .................................................................................................................... 22 14: (A) Overall graft survival rates in group A (without DSG prophylaxis) and group B (with DSG prophylaxis); (B) Graft survival rate with and without accelerated rejection; (C) Graft survival rate with and without acute rejection (AR); (D) Graft survival rate with and without late AR (LAR) ..................................................................................... 23 15: Comparison of graft survival between acceptably mismatched patients (AM) and nonsensitized (<5% PRA), sensitized (5-85% PRA) and highly sensitized (>85% PRA) patients ............................................................................................................... 29 Confidential. For internal use only. 6 Page 258 of 290 Literature Review: The Impact of Transfusion on Transplantation Project Objectives This literature review was undertaken t o summarize published and reported evidence demonstrating t he im pact o f allosensitization a nd p re-transplant transfusions o n transplant matching, wait times and renal allograft survival. To enable the presentation of the evidence to support MedCAC discussions, this document follows an o utline that w ould support examination of the re lationship between transfusions and transplantation. Each chapter of this document addresses a distinct aspect of this relationship, which can be summarized as described below. 1. Transfusions elevate levels of panel reactive antibodies (PRAs). 2. Elevated levels of PRAs make finding transplant matching more difficult, increasing wait times. 3. PRAs and increased wait times both negatively impact the likelihood of successful transplantation. 4. Sensitization remains a significant challenge in management of the ESRD patient despite s trategies t o m itigate th e r isk o f sensitization a nd s ubsequent g raft failure (such as leukoreduction, pre-transplant desensitization, and immunosuppression protocols). Project Methodology HERON conducted an independent, comprehensive review of t he l iterature based on focused keyword searches of MEDLINE. Studies of interest were restricted to the most recent ten years of English-language publications. As t his review concerns t he i mpact o f p rior t ransfusion o n transplantation, particularly in terms of the likelihood of graft rejection and reaction to antigens on the new tissue, the search facets comprised the following: • Transfusion • Transplantation and graft survival • Antigens and histocompatibility The overall search strategy was to produce sub-searches for each of these facets, which were then combined and restricted to date limits and to kidney transplants as the organ of interest. Further details of the search strategy are presented in Appendix A. Where literature referenced publicly available and relevant data sources, HERON examined the most r ecent r eports to gather up -to-date supporting d ata. In a ddition, HERON c onducted focused s earches within the re fined search re sults t o uncover findings o f i nterest re garding leukoreduction, d esensitization and i mmunosuppression p rotocols. La stly, HERON i dentified studies based on reference searching of articles returned by the search. To identify abstracts of interest in addition to published studies, HERON also searched conference proceedings from 2008-2010 meetings of The American Association of Blood Banks (AABB), The American S ociety o f Hematology ( ASH), and T he National Kid ney F oundation ( NKF). La stly, HERON searched the websites of AABB and The American Society of Transplant (AST) in order to identify position papers containing relevant data on transfusions and transplantation. Confidential. For internal use only. 7 Page 259 of 290 Literature Review: The Impact of Transfusion on Transplantation 1 The relationship between transfusions and panel reactive antibodies 1.1 Summary • • • 1.2 The three p rincipal c auses o f a ntibody d evelopment a re p revious t ransplantation, pregnancy and transfusions. Retrospective studies have found that multiple transfusions correspond to increased antibody development, and that levels of sensitization increase with the number of units of blood transfused. Statistical analyses of prior transfusion as a risk factor for sensitization have found that prior transfusion is not c onsistently identified as a n independent predictor of hypersensitization; however, va riability in t he num ber o f units t ransfused and confounding procedures may have influenced these results. Overview of panel reactive antibodies A possible complication of transfusion is the development of antibodies. Panel reactive antibody (PRA) is a test that measures anti-human antibodies in the blood and is routinely performed on patients waiting for kidney and heart transplants (Opelz 2005). PRA has been the measure of sensitization since t he re cognition that c atastrophic hyp eracute rejection w as a ssociated with anti-donor antibodies to human leukocyte antigen (HLA) in the mid-1960s (Cecka 2010). Patients with elevated PRA levels are often referred to as sensitized. The PRA level is defined as the p ercentage o f t he p opulation against which a p otential kidney t ransplant re cipient is sensitized. Although definitions may vary, a PRA level of less than 10 percent indicates that a potential recipient is not sensitized, whereas a level of greater than 80 percent indicates high sensitization (Cecka 2010) (US Renal Data System 2010). Proficiency testing of complement dependent c ytotoxicity ( CDC) assays has shown t hat d ifferent l aboratories c an a ssign widely varying (5 to 80%) PRA values. Another more reproducible definition of sensitization can be derived fro m t he num ber o f s pecificities t o H LA a ntibodies o f a p atient i n re lation t o the frequencies of t he t arget a ntigens i n t he d onor p opulation ( percentage PRA t o percentage population PRAs) (Claas 2009b). Despite the variability noted above, CDC assays are currently the gold standard in most transplant matching programs. Newer solid phase HLA antibody detection assays such as ELISA, Flow-PRA®, and Luminex® are more sensitive than the standard CDC assay, although the clinical relevance of the antibodies detected has yet to be established. Therefore, CDC-dependent crossmatch because of donor HLA-specific antibodies is considered to be a contraindication for transplantation, while antibodies d etected in t he s olid p hase are c urrently c onsidered ri sk fa ctors ( Claas 20 09a). Unresolved issues related to newer assays are addressed in Section 5.6. Confidential. For internal use only. 8 Page 260 of 290 Literature Review: The Impact of Transfusion on Transplantation 1.3 Evidence of the correlation between transfusions and antibody development The p resence o f a ntibodies t o H LA h as b een a major o bstacle t o t ransplantation of hig hly sensitized patients (Nikaein 2009). Development of high antibody levels usually results from multiple b lood t ransfusions, p revious f ailed t ransplants, a nd p regnancies (Jordan 2003) . In addition, in regraft patients, previous graft rejection appears to be associated with the production of HLA antibodies and high levels of sensitization (Hardy 2001). Although nephrologists who treat End-Stage Renal Disease (ESRD) patients are aware of this risk and may attempt to avoid unnecessary transfusions, a significant proportion of potential kidney transplant c andidates c ontinue t o p eriodically re quire b lood t ransfusions t hat c arry a ris k o f allosensitization (Karpinski 2004; Nikaein 2009). The United Network for Organ Sharing (UNOS) database indicates that approximately 30 percent of waitlisted transplant candidates continue to require b lood t ransfusions a t some p oint b efore transplantation (Karpinski 2 004). Likewise, according to the most recently available data from the United States Renal Data System (USRDS), approximately 30 percent of transplant candidates in 2007 had evidence of at least one blood transfusion within t hree years o f b eing a dded t o t he l ist (US R enal D ata S ystem 201 0). In addition, the use of blood transfusions was greater among patients highly sensitized at the time of transplant (US Renal Data System 2010). Prior studies and clinical observations have shown that historical anti-HLA antibodies can become apparent after b lood t ransfusions (Aalten 2009) . In a ddition, p rior t ransfusion ha s been correlated to highly elevated PRAs in clinical studies, as described below. In a retrospective study of 244 patients on a renal transplant waiting list, Soosay et al. identified a relationship between prior transfusion and the risk of allosensitization, as illustrated in Table 1. Transfusion of one or more units of blood was documented in 173 (71%) of subjects. Of the highly sensitized patients (HSPs) (n= 31), 100 percent had received transfusion of at least one unit, in addition to other sensitizing events (Soosay 2003). Table 1: Percentage of sensitizing events in each PRA category Sensitizing Events Transfusion Pregnancy Grafting Not Sensitized PRA 0−9% 60 18 8 Sensitized PRA 10−59% 83 26 43 Significant Sensitization PRA 60−79% 80 47 47 Highly Sensitized PRA 80−100% 100 32 74 In this same retrospective analysis, the level of sensitization clearly increased with the number of red blood cell units transfused. Non-sensitized subjects received a mean of 5.65 units with a standard error of the mean (SEM) of 1.38, while highly sensitized subjects received a mean of 37.8 units (SEM 8.4) (Soosay 2003). Note that the retrospective analysis did not address specific pre-transplant t ransfusion p rotocols t hat may ha ve b een fo llowed, s o i t i s no t p ossible t o determine from this study if pre-transplant transfusions continued after patients were identified as sensitized. The authors conclude from these data that transfusion remains an important cause of sensitization, despite the perception of reduced need for transfusion in patients with end-stage renal failure due to the availability of recombinant human erythropoietin (Soosay 2003). A correlation between number of units transfused and levels of sensitization measured by PRA assays was also identified in an analysis of patients registered in the UNOS Kidney Transplant Registry between 1995 and 2000, conducted by Hardy et al. (Hardy 2001). As depicted in Figure 1, Hardy et al. found that the incidence of sensitization increased with the number of transfusions and was more pronounced in women than in men (Hardy 2001). Confidential. For internal use only. 9 Page 261 of 290 Literature Review: The Impact of Transfusion on Transplantation Figure 1: Sensitization and transfusions in first transplant patients, 1995-2000 (Hardy 2001) In addition, the authors note that the rates identified may in fact under-report true sensitization rates, as sensitization rates were only reported in patients who were transplanted, and did not include rates present in patients who were not transplanted (Hardy 2001). A retrospective cohort study of 112 patients conducted by Karpinski et al. sought to identify independent risk factors for allosensitization, with a focus on evaluating the impact of the practice of universal leukoreduction in Canada on pre-transplant allosensitization (Karpinski 2004) (see Section 4.2 for additional information regarding leukoreduction). In addition, prior transfusion (five or more) was evaluated as an independent risk factor, as illustrated in Table 2 (Karpinski 2004). Table 2: Risk factors for transfusion-associated allosensitization Flow-PRA® positive pretransfusion Pregnancy Previous transplant ≥5 Previous transfusions Leukoreduction RBC units given (per unit) Risk Factors (RR, 95% CI) Univariate P Multivariate 4.5 (1.9–11) 0.001 2.4 (0.8–7.1) 7.8 (3.1–19.5) 0.001 8.2 (2.8–24) 2.8 (0.9–8.7) 0.08 2.4 (0.6–9.9) 5.1 (2.0–13.1) 0.001 2.6 (0.8–8.8) 0.5 (0.3–1.7) NS 2.0 (0.7–6.0) 1.1 (1.0–1.3) 0.10 1.1 (0.9–1.3) P 0.10 0.0001 NS NS NS 0.10 Prior transfusion was associated with an increased risk of allosensitization, but did not reach statistical significance in multivariate analysis in this study. Note that the number of previous transfusions received w as no t re ported w ithin t his s tudy. T his l imitation i s p otentially o f importance t o und erstanding o f t he find ings, a s S cornik e t a l. observed that s ensitization i s infrequent and transient when patients receive fewer than 20 transfusions (Scornik 2009). A retrospective study of serum samples from 145 patients also reported that more than one prior transfusion contributed to anti-HLA antibody production, although as in Karpinski et al. transfusion was not found to be an independent risk factor upon statistical analysis (Vaidya 2005). This study included patients immunized as a result of acute or chronic rejection (n=22), as well as patients with a history of no more than two prior transfusions (n=20) or pregnancy (n=6) (Vaidya 2005). Neither a single pregnancy nor two prior transfusions were independent variables of immunization in primary transplant recipients (p=0.17, and p=0.42, respectively); however, multiple pregnancies and two prior t ransfusions together were associated w ith a potent immunogenic stimulus (p=0.00001) (Vaidya 2005). Note that this study did not observe the same cut-off of five or more prior transfusions as in Karpinski et al.; this cut-off is supported by Karpinski and by previous studies (Opelz 1981). Confidential. For internal use only. 10 Page 262 of 290 Literature Review: The Impact of Transfusion on Transplantation History of transfusion and number of prior transfusions were likewise not found to be predictive of PRA levels in a cross-sectional study of 98 patients conducted at two dialysis centers by PourReza-Gholi et al (Pour-Reza-Gholi 2005). Pour-Reza-Gholi et al. also found that PRA levels were higher after dialysis procedures than prior to dialysis (p=0.0003), suggesting that, for reasons not well understood, dialysis itself may be a confounding procedure impacting PRA results (PourReza-Gholi 2005). Confidential. For internal use only. 11 Page 263 of 290 Literature Review: The Impact of Transfusion on Transplantation 2 The impact of PRAs on renal transplant matching and wait times 2.1 Summary • • • • 2.2 Patients with performed antibodies against HLA antigens are at risk for hyperacute rejection, accelerated acute rejection, antibody-mediated rejection (AMR), delayed graft function and longer-term complications (Cecka 2010). These risks can be minimized by cross-matching a patient’s specific antibody profile with the graft donor. Patients who are sensitized to a high number of HLA specificities have more difficulty finding an appropriate donor, and typically experience longer wait times as a result. Patients with PRA of 10 percent or lower usually receive a kidney transplant during the first year, whereas patients with PRA in excess of 80 percent usually do not receive a kidney transplant during the first two to three years (Soosay 2003). Only a small percentage of highly-sensitized p atients r eceive a transplant due to elevated PRA levels. Overview of the correlation between PRAs, HLA cross-matching and difficulties in renal transplantation Renal t ransplantation o f a hi ghly s ensitized p atient ( >80% P RA) c an b e d ifficult (DeMeester 2002). The presence of preformed anti-HLA antibodies is a contraindication to transplantation of allografts bearing these HLA types since this carries the risk of hyperacute rejection (Soosay 2003). In addition, a patient may experience other complications, including accelerated acute rejection, AMR, delayed graft function and longer-term complications when transplanted from a donor expressing the target HLA antigens (Cecka 2010). A s pecific antibody p rofile is often p erformed t o maximize the c hances of hig hly s ensitized patients receiving a successful graft (Nikaein 2009). Detecting the presence of antibodies prior to transplantation via cross-matching can help a patient find a suitable donor. However, patients who are sensitized to a large number of HLA specificities have lower chances of receiving a crossmatch negative donor and will typically experience longer wait times (Soosay 2003) (DeMeester 2002). Confidential. For internal use only. 12 Page 264 of 290 Literature Review: The Impact of Transfusion on Transplantation 2.3 Evidence of the correlation between PRAs and wait times in renal transplantation A recent review reported that, although protocols enabling successful transplantation patients with donor-specific antibodies can help ensure early to intermediate-term allograft survival, the identification of donor kidneys for transplant candidates with high levels of circulating antibodies against HLA is a major challenge and results in prolonged waiting times for transplantation (Gloor 2010). A retrospective survey of all patients who were active on the Irish renal transplant waiting list during 1996 demonstrated a clear increase in wait time linked to increased PRA. As illustrated in Table 3, the modal waiting time for patients with a PRA of 81−100 percent was greater than 35 months, while non-sensitized patients had a modal waiting time of 0-5 months with a median waiting time of seven months. Only half of highly sensitized patients received a transplant after five years (Soosay 2003). Table 3: PRA levels in correlation to waiting times PRA<10% 0-5* Waiting times (months) *modal waiting time 10%≥PRA≤80% >15 PRA>80% >35 The same study demonstrated that the majority of highly sensitized patients (52% with PRA of 11−59%; 46% with PRA of 60−79% and 84% with PRA >80%) waited more than fifteen months on o ther f orms o f re nal replacement t herapy, whereas t he m ajority ( 56%) of no n-sensitized patients received a transplant within 10 months (Soosay 2003). A review authored by Jordan et al concluded that patients with PRAs greater than 30 percent have d ouble t he w aiting t ime b efore t ransplantation (Jordan 2003) . S imilarly, patients w ith elevated anti-HLA antibodies often wait extended periods of time for a compatible organ (Jordan 2003). Furthermore, one study found that, while 30 percent of UNOS wait-listed renal transplant candidates are allosensitized, only approximately 10 percent of all transplants are performed in sensitized recipients (Karpinski 2004). United Network for Organ Sharing (UNOS) data indicates that patients with elevated PRAs are less likely to receive a transplant. As illustrated in Figure 2, less than 10 percent of all transplants performed in 1998 had a PRA of greater than 20 percent. Waiting times for patients with PRAs greater than 30 percent were double the time for all other patients (Jordan 2003). Figure 2: Share of transplants performed by PRA status 7 2.5 PRA 0-19% PRA 20-78% PRA 80%+ 90.5 (Jordan 2003) Confidential. For internal use only. 13 Page 265 of 290 Literature Review: The Impact of Transfusion on Transplantation The United States Renal Da ta S ystem ( USRDS) also i llustrates t hat p atients re ceiving blood transfusions and those with elevated PRAs experience longer median wait times for transplantation. As illustrated in Figure 3, patients who report a history of transfusion prior to transplant consistently wait longer for a transplant. Median waiting time (months) Figure 3: Median transplantation wait time by transfusion status (US Renal Data System 2010) In addition, patients with elevated PRAs have historically experienced longer median waiting times, as shown in Figure 4. Figure 4: Observed and projected median wait times by year of listing and PRA (US Renal Data System 2010) Note above that data is projected for more recent years, as a median has not yet been observed (i.e., greater than 50 percent of the patients listed in that year have yet to be transplanted). Estimates of median wait times for these years were made using a linear regression model. Confidential. For internal use only. 14 Page 266 of 290 Literature Review: The Impact of Transfusion on Transplantation 3 The impact of elevated PRA levels and wait times on renal transplant success 3.1 Summary • • • • • 3.2 Although it was once thought that pre-transplant blood transfusions could have a beneficial effect on the outcomes of transplantation, recent studies have shown that pre-transplant transfusions have a deleterious effect on mortality and graft survival, and are associated with increased risk of acute rejection. Patients awaiting renal transplantation are routinely tested for lymphocytotoxic PRA. Elevated PRA levels increase the chances of a patient dying or being removed from the transplant wait list while awaiting a transplant. Elevated PRA levels also impact long-term graft survival, regardless of the level of HLA cross-match achieved in the transplant. Patients with an elevated PRA at the time of transplant have shorter graft half-lives (Jordan 2003). Patients with renal dysfunction who have not undergone transplantation have lower survival rates compared to patients who have received kidney transplants (Soosay 2003). In addition, increased morbidity correlates with increased renal dysfunction. Patients experiencing graft loss will die or return to chronic dialysis due to rejection. Overview of PRA levels It has long been known that kidney transplant candidates whose serum contained lymphocytotoxic PRA before transplantation were at increased risk of graft rejection. This finding was published over thirty years ago, and has been confirmed in many subsequent studies. Today patients awaiting renal transplantation routinely undergo PRA testing (Opelz 2005). Patients with high PRA levels experience longer wait times, which may cause them to be delisted or die while awaiting a transplant (US Renal Data System 2010). Thus, a significant proportion of patients with ESRD are denied the benefits of transplantation due to allosensitization (Karpinski 2004). The percentage of sensitized or highly sensitized patients receiving transplants is comparatively low. For example, of the 1,761 patients receiving transplants in the U.S. between 2006 and 2007, 1,469 (83%) had a PRA level of 0-9% at transplant, with sensitized (10-79% PRA) and highly sensitized ( PRA le vel o f 80%+) m aking up o nly 174 ( 10%) a nd 36 ( 2%) o f a ll t ransplants, respectively (US Department of Health and Human Services 2009). 3.3 Elevated PRA levels and increases in wait time correlate to pre-transplant mortality Highly sensitized patients have few options to improve the odds of successful transplantation and wait extended periods of time on dialysis, which is associated with attendant morbidities and mortality (Jordan 2003). Confidential. For internal use only. 15 Page 267 of 290 Literature Review: The Impact of Transfusion on Transplantation In an Irish study of 244 patients on waiting list for kidney transplant, Soosay et al. found that, of 14 patients dying before receiving transplants, 43 percent of those who died were on the waiting list for 2-3 years, while 28.6 percent who died were on the list for 1-2 years. Only 4 patients (28.6%) died within one year of being listed for transplantation (Soosay 2003). Data supplied by the USRDS also show that patients with high PRA levels were more likely to be removed from the transplant list or die while waiting for a transplant, as illustrated in Figure 5. Figure 5: 3-year outcomes of first-time waitlisted patients in 2005 by PRA level (US Renal Data System 2010) 3.4 Evidence of elevated PRAs impacting graft survival and post-transplant complications Transplantation of incompatible organs with positive antibody cross-matches usually results in severe rejection a nd a llograft loss. I n a ddition, elevated P RA levels a re associated with significantly shorter g raft ha lf-life in patients re ceiving b oth t ransplants fro m b oth l iving a nd cadaver sources (Jordan 2003). Data supplied b y t he Org an P rocurement a nd Transplantation N etwork’s ( OPTN) S cientific Registry o f Transplant Recipients ( SRTR) il lustrates t he im pact o f e levated P RA a t time o f transplant on graft survival. As shown in Figure 6, numerically far fewer patients with elevated (>80%) PRA levels experienced survival of kidney grafts from living and deceased donors at 3 months and one year than patients with low (0-9%) PRA levels (202 vs. 7,181 and 1,272 vs. 15,321, respectively), although the percentage of grafts surviving was similar (98.1% vs. 96.0% and 95. 4% vs . 95. 1%, re spectively). T he d ifference i n g raft s urvival b etween p atients w ith elevated and low PRA levels appeared to widen at 10 years, with 52.50% graft survival in highPRA living donor and 40.50% in high-PRA deceased donor recipients, in comparison to 58.40% and 43.70% in low-PRA living and deceased donor recipients, respectively. These differences were not reported as having been tested for statistical significance (US Department of Health and Human Services 2009). Confidential. For internal use only. 16 Page 268 of 290 Literature Review: The Impact of Transfusion on Transplantation Figure 6: Unadjusted graft survival for living and deceased donor transplants, by PRA Unadjusted Graft Survival, Living Donor Kidney Transplants Survival at 3 Months, 1 Year, 5 Years, and 10 Years Total PRA at Transplant 3 Months 1 Year 5 Years 10 Years (Tx 2006 - 2007) (Tx 2006 - 2007) (Tx 2002 - 2007) (Tx 1997 - 2007) N % Std. Err. N % Std. Err. N % Std. Err. N % All 12,462 98.10% 0.10% 12,462 96.30% 0.20% 38,350 81.40% 0.30% 62,864 59.40% 0-9% 7,181 98.10% 0.20% 7,181 96.50% 0.20% 20,112 81.70% 0.40% 30,097 58.40% 10-79% 1,141 98.20% 0.40% 1,141 96.30% 0.60% 2,702 79.90% 1.20% 3,632 53.50% 80%+ 202 96.00% 1.40% 202 93.50% 1.70% 517 69.20% 3.20% 651 52.90% Unknow n 3,938 98.10% 0.20% 3,938 96.10% 0.30% 15,019 81.60% 0.40% 28,484 60.50% Unadjusted Graft Survival, Deceased Donor Kidney Transplants Survival at 3 Months, 1 Year, 5 Years, and 10 Years Total PRA at Transplant 3 Months 1 Year 5 Years 10 Years (Tx 2006 - 2007) (Tx 2006 - 2007) (Tx 2002 - 2007) (Tx 1997 - 2007) N % Std. Err. N % Std. Err. N % Std. Err. N % All 20,298 95.30% 0.10% 20,298 91.00% 0.20% 55,513 69.30% 0.30% 94,990 43.30% 0-9% 15,321 95.40% 0.20% 15,321 91.20% 0.20% 42,316 69.60% 0.30% 72,885 43.70% 10-79% 2,970 94.80% 0.40% 2,970 90.10% 0.60% 7,352 67.90% 0.80% 11,839 40.60% 80%+ 1,272 95.10% 0.60% 1,272 90.30% 0.80% 3,064 68.80% 1.20% 4,491 40.50% Unknow n 735 95.00% 0.80% 735 90.40% 1.10% 2,781 67.90% 1.10% 5,775 45.20% (US Department of Health and Human Services 2009) It is important to note that reports commenting on the OPTN/SRTR data extracts do not identify confounding factors in the high-PRA group that received transplants. For example, it is not possible to evaluate the quality of the renal transplant match in this group, which may have influenced the results. As the majority of patients with elevated PRAs have difficulty finding an acceptable match, many are not transplanted as illustrated in Sections 2.3 and 3.3. As a result, it is possible that those patients in the high-PRA group who were transplanted reflect a biased sample of patients who received an acceptable match, which may have positively influenced the data regarding graft survival. An examination of data from the Collaborative Transplant Study also investigated the influence of PRA on g raft s urvival. A significant e ffect o f P RA on o ne-year g raft s urvival was e vident in cadaver transplants (p<0.0001), but no significant effect was noted in transplants from HLAidentical sibling donors (p=0.0831) (Opelz 2005). Immunosuppressive regimens in patients with transplants fro m H LA-identical s ibling d onors i ncluded c yclosporine, t acrolimus a nd re gimens without calcineurin inhibitors; however, intent-to-treat analysis found no significant differences in graft survival rates depending on the regimen used. The differential effect of PRA on survival of transplants from cadaver donors during the first year after transplantation is shown in Figure 7. Confidential. For internal use only. 17 Page 269 of 290 Literature Review: The Impact of Transfusion on Transplantation Figure 7: 10-year graft survival according to pre-transplant PRA, cadaver kidney transplants (Opelz 2005) Interestingly, P RA w as strongly a ssociated with l ong-term g raft l oss in HLA-identical s ibling donors, even though HLA-identical sibling donors do not provide a target for antibodies to HLA antigens and should therefore not be affected by PRA. Among the patients studied receiving HLAidentical sibling transplants, 3,001 patients with no PRA had significantly higher 10-year graft survival to the 803 patients with 1-50 percent PRA (p=0.0006) or to the 244 patients with greater than 50 percent PRA (p<0.0001) (Table 4). Table 4: 10-year graft survival by PRA level, HLA-identical sibling transplants PRA=0% % graft survival 72.4% (Opelz 2005) 1%≥PRA≤50% PRA>50% SE % graft survival SE % graft survival SE 1.1 63.3% 2.5 55.5% 4.0 The e ffect o f P RA i n H LA-identical sibling t ransplants w as d ifferent fro m t he a cute re jection associated with PRA in recipients of cadaver kidneys. In addition, the authors comment that for the HLA-identical grafts, it is difficult to say whether PRA served as an indicator of heightened immunity against non-HLA transplantation antigens, or whether graft loss was a direct effect of non-HLA humoral sensitization (Opelz 2005). Another study comparing graft outcomes in sensitized and less sensitized patients focused on higher-PRA t hird re nal t ransplant re cipients (TRTR) and lower-PRA p rimary re nal transplant recipients ( PRTR). T his study d emonstrated th at t he p ercentage of P RA in TRTR and P RTR patients ( 24%+34% vs . 7% +14%, re spectively, p= 0.03) c orresponded with d elayed g raft function (defined as the need for dialysis within the first seven days after transplantation) and rejection episodes. F orty-six p ercent o f s ensitized T RTR p atients e xperienced d elayed g raft function compared with 22 percent of PRTR patients (p=0.05), while 50 percent of TRTR patients experienced bio psy-proven rejection e pisodes compared w ith 29 percent of P RTR p atients (p=0.01), despite greater frequency of induction therapy (74% vs. 35%, respectively, p=0.004) (Horovitz 2009). The differences in 1- and 5-year patient survival in the TRTR and PRTR patient groups were not as marked, with both cohorts experiencing similar survival rates (93%, 83% and Confidential. For internal use only. 18 Page 270 of 290 Literature Review: The Impact of Transfusion on Transplantation 96%, 87%, respectively), and similar renal function. However, as illustrated in Figure 8, highlysensitized TRTR p atients experienced more b acterial i nfections ( 43%) a nd w ound p roblems (28%) t han t heir P RTR c ounterparts ( 18% a nd 11%, p= 0.001 a nd p= 0.09, r espectively) (Horovitz 2009). Percentage of total population Figure 8: Post-transplant complications in highly-sensitized TRTR vs. PRTR patients 50 45 40 35 30 25 20 15 10 5 0 TRTR PRTR (Horovitz 2009) It is im portant t o no te t hat t he int ent o f t his re trospective a nalysis w as t o i dentify w hether acceptable medical a nd s urgical o utcomes c ould b e a chieved i n T RTR p atients, d espite t heir higher im munologic and s urgical risks, i n a ddition t o i ncreased m orbidity i n t his p opulation. These risks may not be presented in the populations analyzed in the other studies reviewed for this report. In a single-center, prospective study involving six highly-sensitized patients treated preoperatively with protein A immunoadsorption, one-year graft survival was reported as 66 percent (Hickstein 2002). The one patient in whom the graft did not survive beyond 2 months was also the patient with the highest PRA level reported (80%) following the protein A immunoadsorption procedure (Hickstein 2002); of note, however, high levels of sensitization among these six patients were related to either prior transplant or pregnancy rather than transfusion. 3.5 Evidence of blood transfusions impacting graft survival In the past, some transplant programs administered pre-transplant transfusions deliberately to achieve a beneficial “transfusion e ffect” aimed at o ptimizing g raft o utcomes. H owever, m ore recent data indicate that this beneficial effect is no longer apparent (Karpinski 2004) (Hardy 2001). One analysis of UNOS Kidney Transplant Registry data has even identified the interval from 1995-2000 as the pivotal period when DST ceased demonstrating a beneficial effect on graft survival and began to show a deleterious effect (Hardy 2001). As illustrated in Figure 9, this analysis found that among sensitized and non-sensitized patients alike, those with no transfusions had the highest graft survival, while those with the greatest number of transfusions had the lowest survival. Confidential. For internal use only. 19 Page 271 of 290 Literature Review: The Impact of Transfusion on Transplantation Figure 9: Effect of transfusions on graft survival in non-sensitized (PRA<10%) and sensitized patients (Hardy 2001) (Note: p-value not reported) Note that these data may not be representative of current clinical practices, which may restrict transplantation if high amounts of DSAs are detected prior to transplant. One study of 77 living donor living transplants identified the risk factors associated with graft rejection. E leven p atients l ost their g rafts (6 fro m li ving unre lated d onors and 5 fro m l iving related donors), seven of which were due to chronic rejection (n=7). Overall 3-, 5- and 10-year graft survival in live donors was 92.8 percent, 86.6 percent, and 76.9 percent, respectively. The study found acute rejection episodes, especially 3 or more episodes (risk ratio [RR] = 11.1) and preoperative multiple transfusion history (RR = 4.2) were the primary factors influencing graft survival (Park 2004). One Dut ch study c ompared t he outcomes of re nal t ransplants in p atients w ho ha d r eceived random pre-transplant blood transfusions (rPTF), matched (mPTF), donor-specific blood transfusion (DST) and those who received no PTF. The outcomes showed that PTF did not have a beneficial e ffect o n t he outcomes o f t ransplantation. I nstead, rPTF was associated w ith a significantly increased risk of acute rejection (Figure 10) and a deleterious effect on 10-year cadaver-donor renal graft survival (Figure 11), although the latter result did not achieve statistical significance in this study (Aalten 2009). In addition, as illustrated in Figure 12, DST was not associated with a significant impact on 8-year living-donor renal graft survival. Figure 10: Acute rejection rate within 3 months of transplantation in recipients of a pre-transplant transfusion (rPTF) vs. controls (p < 0.05) (Aalten 2009) Confidential. For internal use only. 20 Page 272 of 290 Literature Review: The Impact of Transfusion on Transplantation Figure 11: Death-censored 10-year graft survival in recipients of a kidney from a deceased donor: rPTF versus no rPTF (p=0.77) (Aalten 2009) Figure 12: Death-censored 8-year graft survival in recipients of a kidney from a living donor: mPTF versus DST versus no PTF group (p=0.96) (Aalten 2009) Confidential. For internal use only. 21 Page 273 of 290 Literature Review: The Impact of Transfusion on Transplantation Although the above-referenced studies by Park and Aalten have reported a deleterious effect of prior transfusion on graft survival, others report a beneficial effect of DST in combination with specific cyclosporine-based immune suppressive protocols. A study by Marti et al. that sought to evaluate the benefits of a cyclosporine-based pre-transplant DST protocols reported 6-year graft survival for a cohort of patients who received pre-transplant DST. The outcomes of 61 patients who had received pre-transplant DST and cyclosporine (the ‘Bern’ group) were compared with subjects from Swiss transplant centers (n=513) and Western Europe (n=7,024). Additionally, a ‘Matched-Cases’ group (n= 55), a control for relevant factors influencing outcome, was created to ensure that study findings reflected the effects of DST rather than patient selection. As illustrated in Figure 13, the study revealed 6-year graft survival rates of 98%, 82%, 84% and 81% in patients in the ‘Bern’, ‘Matched Cases’, ‘Switzerland’ and ‘Western Europe arms, respectively. On an intent-to-treat basis, 6-year graft survival in the ‘Bern’ group with pre-transplant DST was 88.5 percent (Marti 2006). Figure 13: Graft survival after living renal allograft transplantation in patients with and without DST (Marti 2006) (non-ITT analysis) Similarly, a retrospective analysis of 64 patients transplanted following a cyclosporine-based pretransplant DST protocol was undertaken by Barbari et al. in order to evaluate the benefits of DST in light of the availability of cyclosporine A (Barbari 2001). In a combined group of patients treated with pre-transplant DST and various immune suppressive protocols based on azathioprine and cyclosporine A (n= 44), rejection rates were found to be lower than in a historical control group of patients who did not receive pre-transplant cyclosporine A and DST (45% vs. 75%, p<0.02) (Barbari 2001). However, the finding that the results were most pronounced when comparing b etween a g roup o f p atients w ith p re-transplant D ST a nd c yclosporine A vs . t he control g roup w ith no p re-transplant im munosuppression o r DST ( 39% v s. 75 %, p <0.01) suggests that the benefit may be attributable to pre-transplant cyclosporine A rather than DST. Amada et al. studied t wo g roups of DS T p atients i n an attempt t o e stablish t he e ffect of deoxyspergualin (DSG) prophylaxis. A historical control group (Group A) who received cyclosporine, p rednisolone, a nd antilymphocyte g lobulin w ith ( n= 15) o r w ithout azathioprine (n=49) was c ompared with DS G-treated p atients ( Group B) receiving immunosuppressive treatment c onsisting o f c yclosporine, p rednisolone, and a ntilymphocyte g lobulin and deoxyspergualin (n=76) (Amada 2003). As illustrated in Figure 14, overall five-year graft survival rates were significantly higher for group B than group A (89.5 vs. 73.4 percent (p= 0.0070). Subdivision b y re jection type ( accelerated r ejection, A cc; acute rejection, A R; a nd l ate a cute rejection, LAR), revealed that in non-DSG treated patients (group A) five-year graft survival was not affected by the presence or absence of Acc (75.0 vs. 73.1%), but was influenced by the Confidential. For internal use only. 22 Page 274 of 290 Literature Review: The Impact of Transfusion on Transplantation presence of absence of AR (50.0 vs. 85.7%, p=0.0012) or LAR (46.7 vs. 81.6%, p<0.0001). In patients receiving DSG, five-year graft survival did not change significantly by the presence or absence of Acc (100 vs. 88.7%), AR (81.8 vs. 92.6%), or LAR (81.0 vs. 92.7%) (Amada 2003). Figure 14: (A) Overall graft survival rates in group A (without DSG prophylaxis) and group B (with DSG prophylaxis); (B) Graft survival rate with and without accelerated rejection; (C) Graft survival rate with and without acute rejection (AR); (D) Graft survival rate with and without late AR (LAR) (Amada 2003) Confidential. For internal use only. 23 Page 275 of 290 Literature Review: The Impact of Transfusion on Transplantation 4 The evidence supporting strategies to mitigate the risk of graft failure 4.1 Summary • • • • 4.2 Strategies to mitigate the risk of sensitization and subsequent graft failure include leukoreduction, as well as pre-transplant desensitization and immunosuppression at the time of transplant or shortly thereafter. Despite universal leukoreduction policies in several countries, sensitization continues to be identified by sensitive PRA assays. Pre-transplant d esensitization a nd i mmunosuppression p rotocols a re no t fo llowed consistently due to lack of clear guidelines supporting their efficacy. Immunosuppression is associated with significant costs. Leukoreduction of the blood supply and impact on allosensitization Historically reserved for specific patient populations (including dialysis), leukoreduction of red blood cell (RBC) transfusions has now been recommended for universal adoption in Canada, the United Kingdom, France and Portugal. In the US, approximately 70 percent of RBC units are currently leukoreduced prior to distribution (Karpinski 2004). However, there are comparatively few data on the impact of leukoreduction on allosensitization as a result of red blood cell transfusions in patients with ESRD (Karpinski 2004). As previously discussed in Section 1.3, Karpinski et al. evaluated the impact of universal leukoreduction in Canada on p re-transplant a llosensitization i n a r etrospective cohort study o f 112 p atients (Karpinski 2004). Multivariate analysis did not identify leukoreduction as a significant risk factor in t his s tudy ( RR, 2. 0; 9 5% C I, 0. 7-6.0; p = NS), and w as t herefore no t a ssociated w ith a ny protective effect against transfusion-associated allosensitization for potential kidney transplant candidates (Karpinski 2004) (see also Table 2). The findings presented in Sections 0-3 of this report underscore that despite the broad availability of leukoreduced blood products from the late 1990s, evidence of allosensitization remains an area of current investigation and clinical significance, particularly for patients awaiting organ transplantation. Recently, fi ndings fro m a c omparative analysis o f C lass I and C lass I I H LA antibodies in recipients of non-leukoreduced and leukoreduced blood were presented at the 2010 Annual Meeting of the American Association of Blood Banks (AABB) (Norris 2010). This analysis tested longitudinal panels at pre- and post-transfusion time points from 29 recipients of nonleukoreduced blood in the Transfusion-Transmitted Viruses Study (TTVS) and 20 recipients of leukoreduced blood in the Transfusion-Related Infections Prospective Study (TRIPS). While the analysis did reveal that the development of new HLA antibodies was more frequent in panels from patients who received non-leukoreduced blood (p<0.01), the authors observed frequent alloimmunization i n re cipients o f l eukoreduced blo od. Ap plication o f a s ensitive a ssay cutoff (normalized background (NBG) ratio 2.2) revealed that 31 percent of the leukoreduced blood recipients were sensitized to Class I HLA antibodies (Norris 2010). Confidential. For internal use only. 24 Page 276 of 290 Literature Review: The Impact of Transfusion on Transplantation 4.3 Desensitization protocols and experimental induction therapy agents Many highly allosensitized patients may never have an acceptable donor identified, and these patients w ill remain o n d ialysis i ndefinitely. To a ddress t his challenge, strategies h ave b een developed that will allow positive-crossmatch transplantation via patient desensitization, which involves the temporary removal of donor specific antibodies (Gloor 2010; Claas 2009b). The goal of desensitization protocols is to lower donor specific antibody (DSA) activity to avoid immediate allograft injury, and to maintain reduced levels for the first weeks and months after transplantation. It appears that this period of desensitization will allow the allograft to develop a degree of “accommodation,” or relative resistance to AMR (Gloor 2010). Antibody mediated injury may occur minutes or hours after transplantation, as in the case of hyperacute rejections, or days after transplantation, when memory B lymphocytes in the bone marrow, spleen and lymph nodes undergo a reaction causing antibody-secreting cells to produce high levels of DSAs (Gloor 2010). Desensitization protocols va ry w idely, a nd e ncompass b oth p lasma e xchange a nd i nduction therapies. Plasma exchange may involve plasmapheresis with low-dose or high-dose intravenous immunoglobulin (IvIG) and/or immunoabsorption (Claas 2009b). Regarding the latter approach, Hickstein et al. report superior one-year graft survival results in highly sensitized patients treated with protein A immunoadsorption immediately prior to surgery (Hickstein 2002). However, the authors note that prospective multicenter trials would be required to validate this experience (Hickstein 2002). Induction immunosuppressive therapies m ay invo lve antithymoglobin, a nti-interleukin-2 antibodies, or alemtuzumab (Campath 1-H) (Claas 2009b). Rituximab may be used in high-risk patients who become refractory to standard desensitization treatment, or to treat AMR (Kopchaliiska 2009). Some small studies have reported that bortezomib (VELCADE®), a treatment approved for use in plasma-derived cancers, has offered some benefit for patients experiencing AMR, p ossibly b ecause p lasma c ells are re sponsible fo r p roducing H LA a lloantibodies (Claas 2009b). Although some desensitization regimens have been used for almost 20 years, most protocols are still associated with significant challenges and costs. Firstly, patients with high DSA levels at baseline are often resistant to treatment and are unable to proceed with transplantation (Gloor 2010). In addition, as illustrated in Table 5, studies of patients undergoing positive crossmatch transplantation experience high rates of AMR regardless of the method used to desensitize the patient. AMR is a recognized risk factor in poor graft outcome in terms of graft survival and glomerulopathy (Gloor 2010). Table 5: Acute AMR incidence as reported in six separate studies Study Number of patients (Lefaucheur 2009) 43 (Thielke 2009) 51 (Magee 2008) 28 (Haririan 2009) 41 (Vo 2008) 8 Adapted from (Gloor 2010) Confidential. For internal use only. AMR incidence % 35 32 39 12 31 25 Page 277 of 290 Literature Review: The Impact of Transfusion on Transplantation Additional efficacy and safety concerns for various interventions have also been identified by Gloor et al. Plasma exchange, supplemented by IvIG therapy, appears less effective than IvIG therapy alone in patients receiving a deceased donor transplantation, as patents’ DSA levels will return to pretreatment levels upon discontinuation of therapy (Gloor 2010). High-dose IvIG is also associated with s afety c oncerns, i ncluding a dverse a dministration-related ev ents, a naphylactic transfusion reactions and serious thrombotic events. Administration of large fluid volumes may also be difficult in anuric patients undergoing renal dialysis (Gloor 2010). Lastly, each of these interventions is associated with increased resource utilization, as well as therapy c osts. J ordan e t a l. re ported t hat o ne i nstitution’s a verage p er p atient c ost f or a n antibody lowering protocol was $35,540 (Jordan 2003). 4.4 Variance in post-transplant immunosuppressant protocols and associated costs Advances in im munosuppressive t herapies are g enerally c redited w ith c orresponding improvements in hig her survival ra tes o f ki dney a llografts ( Haberal 2002; T urkowski-Duhem 2005), as further described below. A retrospective cohort study of 164 patients by Toki et al. observed a statistically significant difference in the incidence of graft loss according to the era in which the transplantation occurred (era 1 vs. 2 vs. 3 12 vs. 2 vs. 0%, respectively; p=0.009, chi-square test) (Toki 2009). The study defined eras by immunosuppressant regimen as described in Table 6. Table 6: Immunosuppressive regimens, 1990-2007 (Toki 2009) Era 1 Years 1990-2000 2 3 2001-2004 2005-2007 Regimen(s) Cyclosporine or tacrolimus (FK)/azathioprine or mizoribine, or mycophenolate mofetil (MMF)/methylprednisolone (MP)/deoxyspergualin/antilymphocyte globulin /splenectomy/irradiation FK/MMF/MP/splenectomy FK/MMF/MP/rituximab Patients (n) 79 37 48 (Toki 2009) As noted a bove, a preoperative t riple-drug i mmunosuppressive re gimen of seven days was introduced in 2001 including FK, MMF, and MP. Additionally, three or four sessions of doublefiltration plasmapheresis were routinely performed to remove anti-A/B antibodies before transplantation, a lthough this w as n ot c onducted postoperatively unle ss a patient d eveloped acute AMR. Targeted maximal IgG/IgM titers at time of transplantation also differed between eras: 1:16 until 2000 and 1:32 thereafter (Toki 2009). A study of 154 renal allograft patients by Lederer et al. investigated the effect of immunosuppressive drugs on antibody-mediated mechanisms impacting graft survival. The study compared the production of anti-HLA antibodies and DSAs in kidney and pancreas transplant patients receiving differing immunosuppressive regimens. Group 1 patients (n=60) had received MMF since transplantation in combination with either cyclosporin A or tacrolimus and steroids. Group 2 p atients (n= 29) ha d received an immunosuppressive re gimen of cyclosporin A, tacrolimus and steroid initially, followed by the later addition of MMF. Group 3 patients (n= 65) received cyclosporin A in combination with azathioprine or tacrolimus and steroids and no MMF. Results revealed that 83.3 percent (50/60) of patients in group 1 had not developed HLA class I or I I a ntibodies, w hereas a l ower p ercentage o f p atients i n g roup 2 a nd 3 d id no t d evelop Confidential. For internal use only. 26 Page 278 of 290 Literature Review: The Impact of Transfusion on Transplantation antibodies (72.4 % (21/29) and 69.2% (45/65), respectively). The proportion of patients with graft rejection episodes (acute and/or chronic rejection) was slightly higher in groups 2 and 3 (34.5% and 36.9%, respectively) than in group 1 (26.6%). However, group 1 patients suffered from higher rates of cytomegalovirus (CMV) infections (43.3%) than group 2 and 3 (54.5% and 16.9%, respectively) (Lederer 2005). Another area of investigation is the role of cytotoxic T lymphocytes, which may become resistant to i mmunosuppressants. A s tudy o f 1 0 p atients b y va n Ka mpen e t a l. fo und a n a ssociation between the presence of cyclosporine-resistant cytotoxic T lymphocytes and early graft rejection and between c yclosporine-sensitive cytotoxic T l ymphocytes a nd a g ood graft survival in transplantation p atients w ith a his torical p ositive c rossmatch. The s tudy c oncluded t hat t he presence of activated cyclosporine resistant donor specific cytotoxic T lymphocytes was associated with early graft loss and rejection, whereas cyclosporine-sensitive cytotoxic T lymphocytes on t he d ay of t ransplantation were associated w ith g ood g raft o utcomes (van Kampen 2002). A s tudy p ublished b y G upta e t al. d istinguished b etween m ethods of t reating a cute c ellular rejection and acute vascular rejection (AVR). While most cases of acute cellular rejection respond to high dose steroids and/or antilymphocyte globulin, acute vascular rejection (AVR) does not respond to increased levels of immunosuppression. The small series of 19 patients found that patients with AVR plasma exchange and monoclonal CD3 antibody responded to treatment and enjoyed n ormal re nal fu nction a t 4 t o 60 ( 27.8 + 20.1) m onths o f f ollow-up (Gupta 2 001). However, the authors stipulate that the response noted was only evaluated prospectively in 19 patients, and that larger controlled studies are indicated to examine the relevance and role of both plasma exchange and monoclonal CD3 antibody therapy (Gupta 2001). Despite evidence of relative effectiveness of the more recent generation of immune suppressive drugs, immunosuppresant protocols continue to vary and are marked by experimentation with new agents. Several studies report using standard triple immunosuppressive protocols involving prednisone/prednisolone, tacrolimus or cyclosporine, MMF or azathioprine, but these studies differ in combination or agents used and doses a dministered (Kreijveld 2007) (Haberal 2 002). Immunosuppression therapy involving monoclonal antibodies, such as rituximab (Rituxan) and alemtuzumab (Campath 1-H), has also been reported (Kopchaliiska 2009) (Claas 2009b). In addition, there are known risk factors associated with various immunosuppressive regimens. In a study of 950 patients, Said et al. identified rare (1.26%) cases of hemolytic uremic syndrome induced b y calcineurin inhibitors ( Said 2010). Turkowski-Duhem et al. observed th at th e antiproliferative drugs are associated with hematological toxicities and that anticalcineurin agents cause some degree of chronic nephrotoxicity, resulting in impaired renal function, both of which are li nked t o a nemia (Turkowski-Duhem 2005) . In addition, in an e xamination of f actors predicting post-transplant anemia (PTA), one multivariate analysis identified a significant association between PTA detected at six months post-transplant and use of sirolimus therapy (OR 12.75 [1.16-140.54]; p= 0.04); note however that this association was not noted at 12-month follow-up (Turkowski-Duhem 2005). Moreover, t he effectiveness of a vailable i mmune s uppressive r egimens m ay b e i mpacted b y medication noncompliance, which has previously been linked to graft failures due to rejection (Cecka 2000). Cecka et al. hypothesize that the high cost of immunosuppressive drugs may contribute to medication noncompliance. In the early 2000s, annual costs reported ranged from $5,700 to $15,000 for standard maintenance immunosuppression (Kasiske 2000). In addition, the costs of drugs for infection prophylaxis, hypertension and cholesterol may make immune suppressive regimens cost-prohibitive for treatment centers (Cecka 2000), particularly as ESRD ancillary drugs move into prospective payment bundle under Medicare. Confidential. For internal use only. 27 Page 279 of 290 Literature Review: The Impact of Transfusion on Transplantation 5 Key Evidence Gaps The authors of the studies reviewed for this report commented on key gaps in current knowledge of the impact of transfusion on transplantation, as highlighted below. 5.1 Inconsistent definition of highly sensitized patient Various studies report different thresholds to establish the clinical definition of elevated PRAs and high allosensitization. Soosay et al. 2003 report a threshold of 80 percent, whereas others report thresholds of 10, 30, or 50 percent. 5.2 Impact of timing of PRA assays on PRA levels Of the studies included in this report, only Pour-Reza-Gholi et al. 2005 (a single-center study) reported the timing of the PRA assay in relation to dialysis procedures. To evaluate the potential impact of the timing of PRA assay testing on levels and graft outcomes, additional studies may be required. 5.3 Reporting of exact number of prior transfusions Of the studies reviewed to date that examine the impact of prior transfusions on PRA levels, only one (Soosay 2003) specifies the exact number of prior transfusions. While Karpinski et al. cite Opelz 1981 as support for five prior transfusions as the minimum cut-off to establish relevance, Karpinski et a l. d o no t ind icate w hether p atients w ho r eceived p rior t ransfusions r eceived between five and 20 prior transfusions, or more than 20 (the point at which the relationship between prior transfusions and allosensitization may become more dependent) (Scornik 2009). 5.4 Under-reporting of true sensitization rates As noted by Hardy et al., true sensitization rates may be under-reported in data sets that only identify PRA levels for patients who are ultimately transplanted, as most patients with elevated PRAs are not transplanted (Hardy 2001). 5.5 Limited data set for post-transplant outcomes in highly sensitized patients In addition, as a relatively low percentage of patients with elevated PRA receive transplants, there is limited data to establish post-transplant mortalities, morbidities or overall survival in this subpopulation of interest. Confidential. For internal use only. 28 Page 280 of 290 Literature Review: The Impact of Transfusion on Transplantation 5.6 Relevance of antibodies detected on newer HLA assays Donor-specific antibody and antibody subtypes detected on newer assays (e.g. Luminex®, FlowPRA®, and ELISA) are currently the subject of study and discussion (Bartel 2007; Toki 2009). However, the presence of specific antigen subclasses continues to be considered a risk factor rather than a contraindication (Claas 2009a). Further studies are necessary to clarify the actual relevance of these findings since high-sensitivity assays, such as Luminex®, will lead to a higher number of highly sensitized patients. A recent article commented that two steps should be taken to resolve the issues presented by newer assays: (1) a general agreement should be reached on the assignment of positive and negative antibody reactivity in Luminex®, and (2) a multicenter study should be conducted to define the clinically relevant parameters for antibodies detectable on Lum inex® (e.g. antibody t iter, i mmunoglobulin s ubclass, a nd c apacity t o fi x c omplement) (Claas 2009a). 5.7 Reports of the positive impact of acceptable mismatch programs on graft survival outcomes in the US Special p rograms e xist t o he lp hig hly s ensitized p atients fi nd a c rossmatch negative donor. Examples include the Eurotransplant (ET) Acceptable Mismatch program, Save Our Souls in the UK, and Regional Organ Procurement program in the US. An acceptable mismatch is defined by an analysis of the HLA typing of panel donors. Donors carrying antigens to which the patient has never formed antibodies are considered an acceptable mismatch (Claas 2004). A study of 112 highly sensitized patients receiving a kidney transplant revealed that acceptably mismatched (AM) patients experience graft survival (87% at two years) identical to that of nonsensitized patients in the ET program (Figure 15); n ote h owever that t his re port d id no t examine the num ber o f sensitized patients enrolling and benefiting from similar programs in the US (Claas 2004). Figure 15: Comparison of graft survival between acceptably mismatched patients (AM) and nonsensitized (<5% PRA), sensitized (5-85% PRA) and highly sensitized (>85% PRA) patients (Claas 2004) Confidential. For internal use only. 29 Page 281 of 290 Literature Review: The Impact of Transfusion on Transplantation 6 Discussion Although nephrologists treating ESRD patients may attempt to avoid unnecessary transfusions, these p atients c ontinue t o re ceive b oth t herapeutic ( donor-specific) t ransfusions a s w ell a s transfusions to achieve target hemoglobin levels. Retrospective analyses of patient data (1995– present) reviewed in Section 1 of this report evidenced an association between pre-transplant transfusion and high levels of sensitization in waitlisted kidney transplant candidates. While the strength of the association varied across the studies, the authors consistently commented that the ris k o f a llosensitization c ontinues to p ose a s ignificant c hallenge to the m anagement o f waitlisted kidney transplant candidates. To provide evidence to address this ongoing challenge, further studies may be required to investigate of the relationship between the number of pretransplant transfusions and the risk of allosensitization. In addition, the current generation of high-sensitivity assays such as Luminex® will lead to a higher num ber o f p atients id entified a s hi ghly s ensitized in t he fut ure. Because t he c linical relevance of the specific subclasses of antigens detected on high-sensitivity assays has not been established in multicenter studies, it is not yet possible to establish a contraindication to kidney transplant b ased o n t he p resence of these antigens. A s a re sult, assessing t he i mpact o f sensitization on graft survival will persist as a management challenge in ESRD. In contrast, c andidates with preformed anti-HLA a ntibodies d etected on CDC assays are contraindicated for transplant due to the risk of hyperacute rejection of kidney allografts. Pretransplant mortality in these patients (as reported in Section 3.3) means that the pool of available patients with high PRA levels receiving a transplant is by definition smaller, which makes studying the im pact o f s ensitization o n g raft survival e ven more d ifficult. De spite t his c hallenge, t he evidence reviewed for this report (Section 3.4) revealed that highly sensitized patients who did receive transplants experienced more rejection of allografts and shorter graft life. Differences in graft survival by level of pre-transplant sensitization were consistently greatest at 10-year followup. As noted above, some waitlisted kidney transplant candidates continue to receive therapeutic pretransplant (donor-specific) transfusions, despite findings suggesting a deleterious effect of this practice on graft survival i n s ensitized a nd n on-sensitized patients ( Section 3.5). Ongoing investigation into the benefits and risks of DST may have been prompted by the availability of new i mmunosuppressants a nd e xperimentation w ith d ifferent re gimens. As a re sult, f urther analysis may be required to evaluate whether DST is an independent risk factor for decreased rejection and/or long-term graft survival. While the evidence reviewed for this report highlighted gaps in current knowledge of the impact of transfusion on transplantation, it is important to note that the appropriate management of pretransplant transfusion remains important in the treatment of the ESRD patient. As discussed in Section 4 of this report, despite broad availability of leukoreduced RBCs, experimentation with desensitization protocols, and growing experience with immune suppressive regimens, sensitization remains r elevant t o c linical p ractice. T he reduction o f unnecessary transfusions through conservative management therefore continues to present an opportunity to address a known risk factor impacting graft and patient survival in the pre-transplant phase. Confidential. For internal use only. 30 Page 282 of 290 Literature Review: The Impact of Transfusion on Transplantation References Aalten J, Bemelman FJ, van den Berg-Loonen EM, Claas FH, Christiaans MH, et al. (2009) Prekidney-transplant blood transfusions do not improve transplantation outcome: a Dutch national study. Nephrol Dial Transplant. 24(8): 2559-2566. Amada N, Okazaki H, Sato T, Miura S, Ohashi Y. (2003) Prophylactic deoxyspergualin treatment in living-related renal-transplant recipients transfused with donor-specific blood. Transplantation. 75(1): 60-66. Barbari A, Stephan A, Masri MA, Joubran N, Dagher O, et al. (2001) Donor specific transfusion in kidney transplantation: effect of different immunosuppressive protocols on graft outcome. Transplant Proc. 33(5): 2787-2788. Bartel G, Wahrmann M, Exner M, Regele H, Schillinger M, et al. (2007) Determinants of the complement-fixing ability of recipient presensitization against HLA antigens. Transplantation. 83(6): 727-733. Cecka JM. (2000) The UNOS Scientific Renal Transplant Registry--2000. Clin Transpl., 1-18. Cecka JM. (2010) Calculated PRA (CPRA): the new measure of sensitization for transplant candidates. Am J Transplant. 10(1): 26-29. Claas FH, Doxiadis II. (2009a) Human leukocyte antigen antibody detection and kidney allocation within Eurotransplant. Hum Immunol. 70(8): 636-639. Claas FH, Doxiadis II. (2009b) Management of the highly sensitized patient. Curr Opin Immunol. 21(5): 569-572. Claas FH, Witvliet MD, Duquesnoy RJ, Persijn GG, Doxiadis II. (2004) The acceptable mismatch program as a fast tool for highly sensitized patients awaiting a cadaveric kidney transplantation: short waiting time and excellent graft outcome. Transplantation. 78(2): 190-193. DeMeester J, Doxiadis II, Persijn GG, Claas FH. (2002) Renal transplantation of highly sensitised patients via prioritised renal allocation programs. Shorter waiting time and above-average graft survival. Nephron. 92(1): 111-119. Gloor J, Stegall MD. (2010) Sensitized renal transplant recipients: current protocols and future directions. Nat Rev Nephrol. 6(5): 297-306. Gupta RK, Nampoory MR, Johny KV, Costandi JN, Nair MP, et al. (2001) Successful therapy of acute vascular rejection with combined plasma-exchange and monoclonal antibody. Transplant Proc. 33(5): 2770-2773. Haberal M, Emiroglu R, Yagmurdur MC, Karakayali H, Moray G, et al. (2002) Results with livingdonor kidney transplants from spouses: fourteen years of experience at our center. Transplant Proc. 34(6): 2410-2411. Hardy S, Lee SH, Terasaki PI. (2001) Sensitization 2001. Clin Transpl., 271-278. Haririan A, Nogueira J, Kukuruga D, Schweitzer E, Hess J, et al. (2009) Positive cross-match living donor kidney transplantation: longer-term outcomes. Am J Transplant. 9(3): 536-542. Hickstein H, Korten G, Bast R, Barz D, Nizze H, et al. (2002) Immunoadsorption of sensitized kidney transplant candidates immediately prior to surgery. Clin Transplant. 16(2): 97-101. Confidential. For internal use only. 31 Page 283 of 290 Literature Review: The Impact of Transfusion on Transplantation Horovitz D, Caumartin Y, Warren J, Sheikh AA, Bloch M, et al. (2009) Outcome of third renal allograft retransplants versus primary transplants from paired donors. Transplantation. 87(8): 1214-1220. Jordan S, Cunningham-Rundles C, McEwan R. (2003) Utility of intravenous immune globulin in kidney transplantation: efficacy, safety, and cost implications. Am J Transplant. 3(6): 653-664. Karpinski M, Pochinco D, Dembinski I, Laidlaw W, Zacharias J, et al. (2004) Leukocyte reduction of red blood cell transfusions does not decrease allosensitization rates in potential kidney transplant candidates. J Am Soc Nephrol. 15(3): 818-824. Kasiske BL, Cohen D, Lucey MR, Neylan JF. (2000) Payment for immunosuppression after organ transplantation. American Society of Transplantation. JAMA. 283(18): 2445-2450. Kopchaliiska D, Zachary AA, Montgomery RA, Leffell MS. (2009) Reconstitution of peripheral allospecific CD19+ B-cell subsets after B-lymphocyte depletion therapy in renal transplant patients. Transplantation. 87(9): 1394-1401. Kreijveld E, Hilbrands LB, van BY, Joosten I, Allebes W. (2007) The presence of donor-specific human leukocyte antigen antibodies does not preclude successful withdrawal of tacrolimus in stable renal transplant recipients. Transplantation. 84(9): 1092-1096. Lederer SR, Friedrich N, Banas B, Welser G, Albert ED, et al. (2005) Effects of mycophenolate mofetil on donor-specific antibody formation in renal transplantation. Clin Transplant. 19(2): 168174. Lefaucheur C, Suberbielle-Boissel C, Hill GS, Nochy D, Andrade J, et al. (2009) Clinical relevance of preformed HLA donor-specific antibodies in kidney transplantation. Contrib Nephrol. 162, 1-12. Magee CC, Felgueiras J, Tinckam K, Malek S, Mah H, et al. (2008) Renal transplantation in patients with positive lymphocytotoxicity crossmatches: one center's experience. Transplantation. 86(1): 96-103. Mai HL, Cesbron A, Brouard S, Blanchol G, Cantarovich D, et al. (2009) Bortezomib in the treatment of antibody-mediated rejection--a report of 3 cases. Clin Transpl., 361-368. Marti HP, Henschkowski J, Laux G, Vogt B, Seiler C, et al. (2006) Effect of donor-specific transfusions on the outcome of renal allografts in the cyclosporine era. Transpl Int. 19(1): 19-26. Nikaein A, Cherikh W, Nelson K, Baker T, Leffell S, et al. (2009) Organ procurement and transplantation network/united network for organ sharing histocompatibility committee collaborative study to evaluate prediction of crossmatch results in highly sensitized patients. Transplantation. 87(4): 557-562. Norris P, Operskalski E, Schechterly C, et al. (2010) HLA alloimmunization after transfusion is frequently detected using a sensitive antibody detection system. Transfusion. 50(2_suppl): 121A. Opelz G. (2005) Non-HLA transplantation immunity revealed by lymphocytotoxic antibodies. Lancet. 365(9470): 1570-1576. Opelz G, Graver B, Mickey MR, Terasaki PI. (1981) Lymphocytotoxic antibody responses to transfusions in potential kidney transplant recipients. Transplantation. 32(3): 177-183. Park YH, Min SK, Lee JN, Lee HH, Jung WK, et al. (2004) Risk factors on graft survival of living donor kidney transplantation. Transplant Proc. 36(7): 2023-2025. Pour-Reza-Gholi F, Daneshvar S, Nafar M, Firouzan A, Farrokhi F, et al. (2005) Potential risk Confidential. For internal use only. 32 Page 284 of 290 Literature Review: The Impact of Transfusion on Transplantation factors for hypersensitization reflected by panel-reactive antibodies in dialysis patients. Transplant Proc. 37(7): 2936-2938. Said T, Al-Otaibi T, Al-Wahaib S, Francis I, Nair MP, et al. (2010) Posttransplantation calcineurin inhibitor-induced hemolytic uremic syndrome: single-center experience. Transplant Proc. 42(3): 814-816. Scornik JC, Schold JD, Bucci M, Meier-Kriesche HU. (2009) Effects of blood transfusions given after renal transplantation. Transplantation. 87(9): 1381-1386. Soosay A, O'Neill D, Counihan A, Hickey D, Keogan M. (2003) Causes of sensitisation in patients awaiting renal transplantation in Ireland. Ir Med J. 96(4): 109-112. Thielke JJ, West-Thielke PM, Herren HL, Bareato U, Ommert T, et al. (2009) Living donor kidney transplantation across positive crossmatch: the University of Illinois at Chicago experience. Transplantation. 87(2): 268-273. Toki D, Ishida H, Horita S, Yamaguchi Y, Tanabe K. (2009) Blood group O recipients associated with early graft deterioration in living ABO-incompatible kidney transplantation. Transplantation. 88(10): 1186-1193. Turkowski-Duhem A, Kamar N, Cointault O, Lavayssiere L, Esposito L, et al. (2005) Predictive factors of postrenal transplant anemia. Transplant Proc. 37(2): 1009-1011. US Department of Health and Human Services HHDoT. (2009) 2009 Annual Report of the U.S. Organ Procurement and Transplantation Network (OPTN) and the Scientific Registry of Transplant Recipients: Transplant Data 1999-2008. Rockville, Md. US Renal Data System. (2010) USRDS 2010 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States. Vaidya S. (2005) Synthesis of new and memory HLA antibodies from acute and chronic rejections versus pregnancies and blood transfusions. Transplant Proc. 37(2): 648-649. van Kampen CA, Roelen DL, Versteeg-van der Voort Maarschalk MF, Hoitsma AJ, Allebes WA, et al. (2002) Activated HLA class I-reactive cytotoxic T lymphocytes associated with a positive historical crossmatch predict early graft failure. Transplantation. 74(8): 1114-1119. Vo AA, Lukovsky M, Toyoda M, Wang J, Reinsmoen NL, et al. (2008) Rituximab and intravenous immune globulin for desensitization during renal transplantation. N Engl J Med. 359(3): 242-251. Confidential. For internal use only. 33 Page 285 of 290 Literature Review: The Impact of Transfusion on Transplantation Appendix A Detailed Search Strategy This p roject concerns t he i mpact of p rior t ransfusion o n t ransplantation, p articularly in terms of the likelihood of graft rejection and reaction to antigens on the new tissue. As such, the search facets proposed are: • Transfusion • Transplantation and graft survival • Antigens and histocompatibility The overall search strategy is to produce sub-searches for each of these then combine them and add any limits identified in the protocol (e.g. date limits). Transfusion Transfusion-related terms w ere id entified b y s earching t he MeSH i ndex f or t he t erm transfusion and adding keyword terms. The transfusion searches are shown in Table 7. Table 7: Search filters for transfusion # 1. 2. 3. Medline “blood transfusion”[Mesh] “transfusion”[All Fields] #1 OR #2 Transplantation and graft survival Terms were identified through a search of the MeSH index for transplant, cytotoxicity and graft survival. Table 8: String for transplantation # Medline 1. “graft survival/immunology”[Mesh] 2. “Transplants”[Mesh:NoExp] 3. “Transplantation”[Mesh:NoExp] 4. “Graft Rejection”[Mesh] 5. “Transplant”[All Fields] 6. “Cytotoxicity, Immunologic”[Mesh] 7. #1 OR #2 OR #3 OR #4 OR #5 OR #6 Antigens and histocompatibility Table 9 shows the antigens and histocompatibility searches. Confidential. For internal use only. 34 Page 286 of 290 Literature Review: The Impact of Transfusion on Transplantation Table 9: String for antigens and histocompatibility # 1. 2. 3. 4. Medline “HLA Antigens/immunology”[Mesh] “PRA/immunology”[Mesh] “Histocompatibility Testing”[Mesh] #1 OR #2 OR #3 Organ restriction Given that the primary organ of interest is the kidneys, an additional facet was used to restrict t he o verall s earch t o kid neys. This p rovides a n ind ication o f alternative s earch approaches. Table 10: String for organ restriction # 1. 2. 3. 4. Medline “Kidney”[Mesh] “Kidney”[All Fields] “Renal”[All Fields] #1 OR #2 OR #3 Combined search strings The i ndividual fa cets c ombined p roduce 437 c itations w hen the kid ney r estriction i s included (792 without kidney restriction). To future refine results, HERON applied the kidney restriction and further limited to the search strategy to ensure that the most recent and relevant information is retrieved. Language limits: • English language only (406 articles total) Date limits for waves of review: • First Wave: Past ten years of articles (62 citations) • Second Wave: Past twenty years of articles (165 citations) • Third Wave: Full history (406 citations) Waves o f re view, c orresponding t o t he t ime p eriods s pecified above, a llow H ERON t o concentrate on the most recent citations first. Subsequent wave(s) of review above were omitted as earlier waves retrieved robust information. Of the 62 citations returned, 50 were identified as relevant upon a first pass detailed review of abstracts, and 40 were identified as high priority upon second pass. Studies were excluded if the primary focus was basic science, animal or pediatric research, or if the studies addressed only antibody screening or diagnostic procedures. Confidential. For internal use only. 35 Appendix D - Guidelines for Blood Transfusion Appendix D - Guidelines for Blood Transfusion Page 287 of 290 Page 287 Page 288 of 290 Appendix D – Guidelines for Blood Transfusion Page 1 INTER/NATIONAL GUIDELINES Source UK Renal Association-clinical practice guideline European Best Practice Guidelines (EBPG) National Kidney Foundation KDOQI™ Position on Pre-Transplant Blood Transfusions Website (if applicable) "We recommend that in patients with anaemia of CKD, especially those in whom renal transplantation is an option, red blood cell transfusion should be avoided if possible. (1A)"; "Also transplant recipient sensitisation may occur following transfusion resulting in longer transplant register waiting times and difficulty in finding a cross match negative donor. A study from Ireland looking at causes of sensitisation of potential allograft recipients showed that the level of sensitisation increased with the number of units of blood transfused and also demonstrated a direct relationship between degree of sensitisation and waiting time for transplantation.3 Blood transfusions can induce antibodies to histocompatibility leukocyte antigens that can reduce the success of kidney transplantation; thus transfusions generally should be avoided in patients awaiting a renal transplant.4" "Red blood cell transfusions should be avoided, if at all possible, in patients with chronic kidney disease (CKD), especially those awaiting kidney transplantation. (Evidence level B)"; "Transfusions should not be given unless patients have one or more of the following: (1) symptomatic anaemia (fatigue, angina, dyspnoea) and/or associated risk factors (diabetes, heart failure, coronary artery disease, arteriopathy, old age) (2) acute worsening of anaemia due to blood loss (haemorrhage or surgery) or haemolysis (3) severe resistance to, or hyporesponsiveness to, ESA therapy, e.g. due to the presence of a haematological disease or severe inflammatory systemic disease." "Blood transfusions can induce antibodies to histocompatibility leukocyte antigens that can reduce the success of kidney transplantation; thus, transfusions generally should be avoided in patients awaiting a renal transplant.267 If deemed essential, red blood cell transfusions in this patient group should be conducted in line with published recommendations.268" http://www.renal.org/Clinical/Guideline sSection/AnaemiaInCKD.aspx Date Accessed 12/17/2010 http://ndt.oxfordjournals.org/content/1 9/suppl_2/ii16.full.pdf+html 12/17/2010 http://www.kidney.org/professionals/k doqi/guidelines_anemia/cpr34.htm 12/17/2010 Page 289 of 290 Appendix D – Guidelines for Blood Transfusion Page 2 LOCAL GUIDELINES Source Position on Pre-Transplant Blood Transfusions Website (if applicable) Date Accessed Northwestern University, Dr. Dixon Kaufman, Director of Pancreas Transplantation Multiple random blood transfusions: Once, this was associated with improved kidney transplant survival in the precyclosporine era. Currently, transfusion offers no clinical benefit, and the risk of sensitization is significant. In the setting of living kidney transplantation, donor-specific transfusion therapy has also has been almost completely eliminated. WebMD: Renal transplantation (Medical): Differential diagnoses & Workup 12/17/2010 http://emedicine.medscape.com/article/ 429314-diagnosis 12/17/2010 UCSF Transplant Center On-line policy on transplant procedures: Crossmatches are obtained several times during preparation for a living-related donor transplant, particularly if donor-specific blood transfusions are used. A final crossmatch is performed within 48 hours before the transplant. http://www.ucsfhealth.org/conditions/kid ney_transplant/diagnosis.html 12/17/2010 University of Wisconsin Letter to the patients: "If you receive a blood transfusion, be sure the blood is “filtered” to avoid developing antibodies (sensitizes you for transplant). Call your coordinator if you receive any blood products." http://www.uwhealth.org/files/uwhealth/ docs/pdf/Volume5_2008.pdf 12/17/2010 VCU Health System Hume-Lee Transplant Center Desensitization Protocol About 30% of patients who are waiting for a kidney transplant are sensitized, meaning that they have developed harmful antibodies in their blood against foreign tissue. These antibodies can develop through previous exposure to foreign tissue resulting from pregnancies, previous transplants, or blood transfusions. This may cause patients to wait three or four times longer than unsensitized patients for a compatible deceased kidney. http://www.vcuhealth.org/upload/docs/T ransplant/pre_op_kidney_booklet.pdf 12/17/2010 Page 290 of 290 Appendix D – Guidelines for Blood Transfusion Page 3 LOCAL GUIDELINES Source Position on Pre-Transplant Blood Transfusions Website (if applicable) Date Accessed http://www.renalmd.org/legis.aspx?id=1 827 12/17/2010 Many sensitized patients have living donors that are willing to give them a kidney, but the transplant has little chance of success. The recipient’s blood, when mixed with the donor’s blood, reacts against the donor’s cells because of the antibodies. This is a positive crossmatch, which means that the recipient will likely reject the kidney immediately following transplant. A negative crossmatch is needed before a transplant can be performed. There is a process that allows the antibodies to be removed from the recipient’s blood called desensitization. This involves the patient undergoing plasmapheresis treatments to help remove the harmful antibodies from the blood. Your doctor will discuss this option in more detail with you if it is needed. Renal Physician’s Association RPA: ESA use for nondialysis CKD patients with Hb<10 gm/dl reduces the need for transfusions and may improve patient reported outcomes. Particularly for patients who are candidates for kidney transplantation, avoidance of blood transfusions may reduce presensitization and improve the likelihood of finding a good donorrecipient match.