The role of different histocompatibility testing methods for selection of related and unrelated bone marrow donors.

Bone marrow transplantation has become the treatment of choice for many hematological malignancies. Approximately 30% of the patients lack an HLA-identical sibling donor, for them alternative donors have to be found. The chances of finding an unrelated donor can be estimated by consulting the Bone Marrow Donors Worldwide file and grouping the patients according to whether they have frequent or rare haplotypes. If the HLA-ABDR split antigens are taken into account, for less than 25% of the patients identical donors can be identified. In order to select the best matched donor for a patient, sensitive HLA typing techniques should be employed including DNA typing techniques, but for optimal selection of a suitable donor one should not only study genetics but also determine the immunological repertoire recognizing the histocompatibility differences between donor and recipient. Several promising cellular techniques such as the HTLp and CTLp test have recently become available and should also be used to select the best donor.