The success of unrelated-donor HSCT transplants is dependent upon human leukocyte antigen (HLA) matching. Researchers from the National Marrow Donor Program recently determined the likelihood of finding a suitable unrelated-donor for 21 different ethnic groups in the U.S. registry, which contains over 10 million adult donors and more than 186,000 cord-blood units. Patient ethnicity significantly influenced whether a suitable adult donor or cord blood unit could be matched. Patients of white European ancestry have the best likelihood (75%) of finding a perfect HLA-matched adult donor, while black Americans have the worst likelihood (16-19%). In addition, because the registry contains fewer cord blood units, the likelihood of finding a perfect match is lower. Although most HSCT patients will be able to find an acceptable match, continued research will improve outcomes for HLA-mismatched grafts.
1. Gragert L, Eapen M, Williams E, Freeman J, Spellman S, Baitty R, Hartzman R, Rizzo JD, Horowitz M, Confer D, Maiers M. HLA match likelihoods for hematopoietic stem-cell grafts in the U.S. registry. N Engl J Med 2014;371: 339-48.