Effect of HLA mismatches on the outcome of hematopoietic transplants.

Hematopoietic cell transplantation from unrelated volunteer donors for the treatment of hematological malignancy can be optimized by complete and precise matching for HLA class I and II alleles between the donor and recipient. Survival is improved when the donor and recipient are matched for HLA-A, -B, -C, -DRB, -DQB1 and -DPB1 alleles. The risks of clinically severe graft-versus-host disease, graft failure and mortality are increased in the presence of multilocus mismatching. These findings demonstrate that HLA allelic differences are biologically relevant in human transplantation.