HLA matching in hematopoietic cell transplantation

Progress in hematopoietic cell transplantation has been greatly facilitated by our increasing knowledge of the HLA system, as well as by improved therapies for achieving sustained engraftment, preventing graft-versus-host disease, and protecting the patient from infection. Disparity for HLA genes can cause graft rejection and graft-versus-host disease and decrease survival in patients receiving grafts from both related and unrelated donors. The presence of patient alloantibodies against donor antigens demonstrated by a positive crossmatch is a strong risk factor for graft rejection. The availability of matched donors for patients lacking a genotypically HLA-matched sibling has been greatly improved by the establishment of international registries of HLA-typed volunteer donors. The development of accurate and reproducible high-resolution DNA-based typing methods has significantly improved the prospects for identifying unrelated donors who are well matched with the patient for HLA. The use of these methods to optimize donor selection will improve both donor identification and the success of unrelated donor transplants.