HLA Markers and Bone Marrow Transplantation
Dr. med. Kaimo Hirv
HLA plays a crucial role during the selection of bone marrow and blood stem cell donors. The allogeneic bone marrow transplantation (BMT) and the peripheral blood stem cell transplantation (PBSCT) is the therapy of choice for malignant diseases and malfunction of the hematopoietic organs. The umbilical cord blood transplantation represents an alternative to blood stem cell or bone marrow transplantation. A generally recognized criterion for a successful transplantation of stem cells is considered to be the tissue tolerance of donor and recipient; i.e. the matching of HLA-A, -B and -C as well as HLA-DRB1 and -DQB1.
Transplantations among genetically HLA-identical siblings as well as among unrelated bone marrow donors (from a bone marrow registry) nowadays bring comparably good results. Since, however, only approx. 35% of all patients in Western Europe have an HLA-identical donor sibling, an increasing number of HLA-identical donors are found through registries. In the consensus paper of the German transplantat physicians and immunogeneticists, the criteria for the selection of a suitable donor from a registry for stem cell transplantation were determined. These criteria demand matching of HLA-A*, -B*, -C* with at least low resolution and of HLA-DRB1* and -DQB1* with high resolution for unrelated BMT. Under consideration of these criteria, donors for approx. 80% of all patients with hematologic diseases who do not have a related donor can currently be found. At present, there are approx. 20 million voluntary donors worldwide, who have been registered anonymously in national (e.g. German National Registry of Blood Stem Cell Donors, ZKRD) or other international registries. The search and referral of BM donors is conducted internationally via the online-linkage of the ZKRD with worldwide registries.