Histocompatible unrelated donors for bone marrow transplantation.

Bone marrow transplantation using HLA one haplotype mismatched family donors has been associated with a high incidence of severe graft-versus-host disease, and an increased risk of graft failure. Recently, the use of histocompatible unrelated donors has been investigated when an HLA genotypically identical sibling is not available. Conventional histocompatibility testing of potential unrelated donors does not always predict alloreactivity in vivo. In this review, the preliminary results of histocompatible unrelated transplants are presented and methods of matching unrelated donors discussed.