Sensitization in Transplantation: Assessment of Risk (STAR) 2017 Working Group Meeting Report.

The presence of preexisting (memory) or de novo donor-specific HLA antibodies (DSAs) is a known barrier to successful long-term organ transplantation. Yet, despite the fact that laboratory tools and our understanding of histocompatibility have advanced significantly in recent years, the criteria to define presence of a DSA and assign a level of risk for a given DSA vary markedly between centers. A collaborative effort between the American Society for Histocompatibility and Immunogenetics and the American Society of Transplantation provided the logistical support for generating a dedicated multidisciplinary working group, which included experts in histocompatibility as well as kidney, liver, heart, and lung transplantation. The goals were to perform a critical review of biologically driven, state-of-the-art, clinical diagnostics literature and to provide clinical practice recommendations based on expert assessment of quality and strength of evidence. The results of the Sensitization in Transplantation: Assessment of Risk (STAR) meeting are summarized here, providing recommendations on the definition and utilization of HLA diagnostic testing, and a framework for clinical assessment of risk for a memory or a primary alloimmune response. The definitions, recommendations, risk framework, and highlighted gaps in knowledge are intended to spur research that will inform the next STAR Working Group meeting in 2019.

The National Marrow Donor Program: improving access to hematopoietic cell transplantation.

Since its founding in 1986, the NMDP has grown into a large international organization, providing patients with access to more than 9.5 million adult donors on the Be The Match Registry and to more than 18.5 million adult donors worldwide. Patients searching through the NMDP also have access to nearly 165,000 CBUs from NMDP-affiliated cord blood banks and nearly 600,000 CBUs worldwide. Through aggressive recruitment to the Be The Match Registry, and by establishing connections to international registries, the NMDP gives patients in need of a transplant access to a large and diverse pool of unrelated donors and CBUs. This has resulted in a steady increase in the likelihood of finding a matching donor or CBU for searching patients of all races/ethnicities. The NMDP has also developed programs and initiatives that have successfully increased the efficiency of the search process, which has decreased the time to transplant. The NMDP has also developed strategies that have improved access to transplant, especially among minority racial/ethnic patient populations. These long-standing and ongoing efforts to grow the Be The Match Registry and to improve the search process resulted in a record number of NMDP-facilitated transplants in 2011--more than 5,500--and now have facilitated more than 50,000 transplants since 1986. However, the NMDP, using SEER data, has calculated that there are approximately 10,000 patients in the U.S. each year who could potentially benefit from unrelated donor HCT. The NMDP has therefore set a goal to facilitate 10,000 transplants annually. Although meeting this goal will require nearly doubling the annual rate of transplants, the NMDP is confident that it has the expertise, personnel, facilities, and commitment to achieve this goal.

Racial and ethnic disparities in kidney transplantation.

Success of renal transplantation, as a viable alternative to dialysis, has been tempered by long-standing racial disparities. Ethnic minorities have less access to transplantation, are less likely to be listed for transplantation, and experience a higher rate of graft failure. Reasons for the existing racial disparities at various stages of the transplantation process are complex and multi-factorial. They include a combination of behavioral, social, environmental, and occupational factors, as well as potential intended or unintended discrimination within the healthcare system. Immunologic factors such as human leukocyte antigen matching, composition of the organ donor pool, and patient immune response, all of which affect post-transplantation graft rejection rates and patient survival, also contribute to health disparities between ethnic groups.

Assessment of optimal size and composition of the U.S. National Registry of hematopoietic stem cell donors.

BACKGROUND: The National Marrow Donor Program (NMDP) receives federal funding to operate a registry of over 4 million volunteer donors for patients in need of a hematopoietic stem cell transplant. Because minority patients are less likely to find a suitably matched donor than whites, special efforts have been aimed toward recruitment of minorities. Significant financial resources are required to recruit and tissue type additional volunteer donors. METHODS: Population genetics models have been constructed to project likelihoods of finding a human leukocyte antigen (HLA)-matched donor for patients of various racial/ethnic groups. These projections have been made under a variety of strategies for expansion of the NMDP Registry. Cost-effectiveness calculations incorporated donor unavailability and other barriers to transplantation. RESULTS: At current recruitment rates, the probability of an available HLA-A,B,DRB1 matched donor is projected to increase from 27% to 34%; 45% to 54%; 75% to 79%; and 48% to 55%, for blacks, Asians/Pacific Islanders, whites and Hispanics, respectively, by the year 2007. Substantial increases in minority recruitment would have only modest impacts on these projections. These projections are heavily affected by donor availability rates, which are less than 50% for minority volunteers. CONCLUSIONS: Continued recruitment of additional volunteers can improve the likelihood of finding an HLA-matched donor, but will still leave significant numbers of patients of all racial/ethnic groups without a match. Efforts to improve donor availability (especially among minorities) and to increase the number of patients with access to the NMDP Registry may prove to be more cost-effective means of increasing transplants.