Alternative donor transplants for leukemia. Scientific Advisory Committee of the International Bone Marrow Transplant Registry.

We analyzed transplant outcome in more than 2,500 recipients of alternative donor and HLA-identical sibling transplants. These data indicate: (1) results of alternative donor transplants are inferior to HLA-identical sibling transplants; (2) zero HLA-antigen disparate unrelated and one HLA-antigen disparate related donors have comparable results; (3) amongst unrelated donors, zero and one HLA-antigen disparity has comparable results; and (4), amongst related transplants, two HLA-antigen disparate transplants fare worse than one HLA-antigen disparate transplants. These data should be useful in deciding when to use an alternative donor and selecting the best donor.