HLA-DP AND ALLOGENEIC BONE-MARROW TRANSPLANTATION

HLA-DP typing is not routinely performed before allogeneic BMT. This h ighly polymorphic class II locus is implicated in immune response and DP molecules may act as transplantation antigens. HLA-DP incompatibili ties contribute to MLC. In BMT performed between siblings, HLA-DP mism atches are rare and the role of such incompatibility in GVHD is probab ly lower than minor histocompatibility antigen disparity. In unrelated BMT, the rate of HLA-DP mismatches is high and DP incompatibility can not be used as an exclusion criterion in the selection of unrelated do nors. Even if in vitro studies show that the HLA-DP antigen may be the target for GVHD, analysis of large numbers of unrelated BMT shows tha t DP incompatibility is not a risk factor for acute GVHD.