HapLogic: A Predictive Human Leukocyte Antigen-Matching Algorithm to Enhance Rapid Identification of the Optimal Unrelated Hematopoietic Stem Cell Sources for Transplantation.

The search for a suitable human leukocyte antigen (HLA)-matched unrelated adult stem cell donor (URD) or umbilical cord blood unit (UCB) is a complex process. The National Marrow Donor Program (NMDP) developed a search algorithm known as HapLogic, which is currently provided within the NMDP Traxis application. The HapLogic algorithm has been in use since 2006 and has advanced URD/UCB HLA-matching technology.

High-Resolution Match Rate of 7/8 and 9/10 or Better for the Be The Match Unrelated Donor Registry.

Estimation of the National Marrow Donor Program's Be The Match Registry 8/8 (HLA-A, -B, -C, and -DRB1) high-resolution (HR) unrelated donor (URD) match rate was determined in a prior study for each of the 4 most frequent patient race/ethnic groups in the United States: white (WH), Hispanic (HIS), Asian/Pacific Islander (API), and African American (AFA). For patients without an 8/8 HLA-matched URD, a 7/8 match, with a single allele or antigen mismatch, is often accepted by many transplant centers. A follow-up study was designed to determine the 7/8 or better match rate among the 4 major race/ethnic groups, using the same study cohort.

The effect of donor characteristics on survival after unrelated donor transplantation for hematologic malignancy.

There are >24 million registered adult donors, and the numbers of unrelated donor transplantations are increasing. The optimal strategy for prioritizing among comparably HLA-matched potential donors has not been established. Therefore, the objective of the current analyses was to study the association between donor characteristics (age, sex, parity, cytomegalovirus serostatus, HLA match, and blood group ABO match) and survival after transplantation for hematologic malignancy.

8/8 and 10/10 high-resolution match rate for the be the match unrelated donor registry.

The National Marrow Donor Program's Be The Match Registry(®) facilitates the worldwide utilization of unrelated donor (URD) grafts for patients in need of a hematopoietic cell transplantation. In this study, we estimate the URD match rate for patients of White (WH), Hispanic (HIS), Asian/Pacific Islander (API), and African American/Black (AFA) race and ethnic groups. We chose 1344 URD at random as "pseudo-patients" (PP) to estimate the likelihood of finding an 8/8 or 10/10 high-resolution HLA-A,-B,-C,-DRB1 (and -DQB1) matched URD.

Identification of a permissible HLA mismatch in hematopoietic stem cell transplantation.

In subjects mismatched in the HLA alleles C*03:03/C*03:04 no allogeneic cytotoxic T-lymphocyte responses are detected in vitro. Hematopoietic stem cell transplantation (HSCT) with unrelated donors (UDs) showed no association between the HLA-C allele mismatches (CAMMs) and adverse outcomes; antigen mismatches at this and mismatches other HLA loci are deleterious. The absence of effect of the CAMM may have resulted from the predominance of the mismatch C*03:03/C*03:04.

Amino acid substitution at peptide-binding pockets of HLA class I molecules increases risk of severe acute GVHD and mortality.

HLA disparity has a negative impact on the outcomes of hematopoietic cell transplantation (HCT). We studied the independent impact of amino acid substitution (AAS) at peptide-binding positions 9, 99, 116, and 156, and killer immunoglobulin-like receptor binding position 77 of HLA-A, B, or C, on the risks for grade 3-4 acute graft-versus-host disease (GVHD), chronic GVHD, treatment-related mortality (TRM), relapse, and overall survival. In multivariate analysis, a mismatch at HLA-C position 116 was associated with increased risk for severe acute GVHD (hazard ratio [HR] = 1.

Multiple mismatches at the low expression HLA loci DP, DQ, and DRB3/4/5 associate with adverse outcomes in hematopoietic stem cell transplantation.

A single mismatch in highly expressed HLA-A, -B, -C, and -DRB1 loci (HEL) is associated with worse outcomes in hematopoietic stem cell transplantation, while less is known about the cumulative impact of mismatches in the lesser expressed HLA loci DRB3/4/5, DQ, and DP (LEL). We studied whether accumulation of LEL mismatches is associated with deleterious effects in 3853 unrelated donor transplants stratified according to number of matches in the HEL. In the 8/8 matched HEL group, LEL mismatches were not associated with any adverse outcome.

Donor registries and search strategies.

The optimal donor of hematopoietic progenitor cells shares alleles of the major histocompatibility genes with the recipient. This chapter describes the strategies aimed at identifying such a matched donor from registries of volunteers or from umbilical cord blood banks.

A perspective on the selection of unrelated donors and cord blood units for transplantation.

Selection of a suitable graft for allogeneic hematopoietic stem cell transplantation involves consideration of both donor and recipient characteristics. Of primary importance is sufficient donor-recipient HLA matching to ensure engraftment and acceptable rates of GVHD. In this Perspective, the National Marrow Donor Program and the Center for International Blood and Marrow Transplant Research provide guidelines, based on large studies correlating graft characteristics with clinical transplantation outcomes, on appropriate typing strategies and matching criteria for unrelated adult donor and cord blood graft selection.

Relationship of race/ethnicity and survival after single umbilical cord blood transplantation for adults and children with leukemia and myelodysplastic syndromes.

The relationship of race/ethnicity with outcomes of umbilical cord blood transplantation (UCBT) is not well known. We analyzed the association between race/ethnicity and outcomes of unrelated single UCBT for leukemia and myelodysplastic syndromes. Our retrospective cohort study consisted of 885 adults and children (612 whites, 145 blacks, and 128 Hispanics) who received unrelated single UCBT for leukemia and myelodysplastic syndromes between 1995 and 2006 and were reported to the Center for International Blood and Marrow Transplant Research.

HLA-C antigen mismatch is associated with worse outcome in unrelated donor peripheral blood stem cell transplantation.

The association between HLA matching and outcome in unrelated-donor peripheral blood stem cell (PBSC) transplantation has not yet been established. In the present study, a total of 1933 unrelated donor-recipient pairs who underwent PBSC transplantation between 1999 and 2006 for acute myelogenous leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome, or chronic myelogenous leukemia and received high-resolution HLA typing for HLA-A, -B, -C, -DRB1, -DQA1, and -DQB1 were included in the analysis. Outcomes were compared between HLA-matched and HLA-mismatched pairs, adjusting for patient and transplant characteristics.

One-antigen mismatched related versus HLA-matched unrelated donor hematopoietic stem cell transplantation in adults with acute leukemia: Center for International Blood and Marrow Transplant Research results in the era of molecular HLA typing.

Approximately 13% of patients lacking an HLA-identical sibling have a one-antigen-mismatched related donor (MMRD). Historically, outcomes from the use of a one-antigen MMRD were considered equivalent to those from the use of a matched unrelated donor (UD). Recent improvements in UD stem cell transplantation (SCT) resulting from better molecular HLA matching justifies investigating whether UD should be preferred over MMRD in adult patients with acute leukemia.

Outcomes of pediatric bone marrow transplantation for leukemia and myelodysplasia using matched sibling, mismatched related, or matched unrelated donors.

Although some trials have allowed matched or single human leukocyte antigen (HLA)-mismatched related donors (mmRDs) along with HLA-matched sibling donors (MSDs) for pediatric bone marrow transplantation in early-stage hematologic malignancies, whether mmRD grafts lead to similar outcomes is not known. We compared patients < 18 years old reported to the Center for International Blood and Marrow Transplant Research with acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, and myelodysplastic syndrome undergoing allogeneic T-replete, myeloablative bone marrow transplantation between 1993 and 2006. In total, patients receiving bone marrow from 1208 MSDs, 266 8/8 allelic-matched unrelated donors (URDs), and 151 0-1 HLA-antigen mmRDs were studied.

Race and socioeconomic status influence outcomes of unrelated donor hematopoietic cell transplantation.

Success of hematopoietic cell transplantation (HCT) can vary by race, but the impact of socioeconomic status (SES) is not known. To evaluate the role of race and SES, we studied 6207 unrelated-donor myeloablative (MA) HCT recipients transplanted between 1995 and 2004 for acute or chronic leukemia or myelodysplastic syndrome (MDS). Patients were reported by transplant center to be White (n = 5253), African American (n = 368), Asian/Pacific-Islander (n = 141), or Hispanic (n = 445).

The effect of the composition of unrelated donor bone marrow and peripheral blood progenitor cell grafts on transplantation outcomes.

To test the hypothesis that the outcome of hematopoietic stem cell (HSC) grafts is at least partially determined by the cellular composition of the graft, the National Marrow Donor Program (NMDP) analyzed the correlation of cellular phenotypes of unrelated grafts with graft outcome. Samples from 94 bone marrow (BM) and 181 peripheral blood progenitor cell (PBPC) grafts for transplantations at 40 U.S.

Unrelated donor hematopoietic cell transplantation: factors associated with a better HLA match.

The impact of non-HLA patient factors on the match of the selected unrelated donor (URD) for hematopoietic cell transplantation (HCT) has not been fully evaluated. National Marrow Donor Program (NMDP) data for 7486 transplants using peripheral blood stem cells (PBSCs) or bone marrow from years 2000 to 2005 were evaluated using multivariate logistic regression to identify independent non-HLA patient factors associated with completing a more closely matched URD transplant. Advanced (intermediate- and late-stage) disease was significantly associated with an increased likelihood of transplant using a less-matched (partially matched or mismatched) donor.

Classification of HLA-matching for retrospective analysis of unrelated donor transplantation: revised definitions to predict survival.

The best unrelated donors (URD) for hematopoietic cell transplantation (HCT) are alleles matched at HLA-A, -B, -C, and DRB1. Earlier studies mostly used incomplete or lower resolution HLA typing for analysis of transplant outcome. To understand the impact of incomplete HLA characterization, we analyzed 14,797 URD HCT (1995-2006) using multivariable regression modeling adjusting for factors affecting survival.

Use of cost-effectiveness analysis to determine inventory size for a national cord blood bank.

Background: Transplantation with stem cells from stored umbilical cord blood units is an alternative to living unrelated bone marrow transplantation. The larger the inventory of stored cord units, the greater the likelihood that transplant candidates will match to a unit, but storing units is costly. The authors present the results of a study, commissioned by the Institute of Medicine, as part of a report on the establishment of a national cord blood bank, examining the optimal inventory level.

Estimation of HLA-A, -B, -DRB1 haplotype frequencies using mixed resolution data from a National Registry with selective retyping of volunteers.

Large registries of volunteer hematopoietic stem cell donors typed for HLA contain potentially valuable data for studying haplotype frequencies in the general population. However the usual assumptions for use of the expectation-maximization (EM) algorithm are typically violated in these registries. To avoid this problem, previous studies using registry data have reduced the HLA typings to low-resolution and/or excluded subjects who were selected for testing on behalf of a specific patient ("patient-directed" typings).

High-resolution donor-recipient HLA matching contributes to the success of unrelated donor marrow transplantation.

The relative importance of various human leukocyte antigen (HLA) loci and the resolution level at which they are matched has not been fully defined for unrelated donor transplantation. To address this question, National Marrow Donor Program data from 3857 transplantations performed from 1988 to 2003 in the United States were analyzed. Patient-donor pairs were fully typed for HLA-A, -B, -C, -DRB1, -DQB1, -DQA1, -DPB1, and -DPA1 alleles.

Common and well-documented HLA alleles: report of the Ad-Hoc committee of the american society for histocompatiblity and immunogenetics.

In histocompatibility testing some genotype ambiguities are almost always resolved into the genotype with the most common alleles. To achieve unambiguous assignments additional unwieldy tests are performed. The American Society for Histocompatibility and Immunogenetics formed a committee to define what human leukocyte antigen (HLA) genotypes do not need to be resolved in external proficiency testing.