HLA-A3 increases and HLA-DR1 decreases the risk of acute graft-versus-host disease after HLA-matched sibling bone marrow transplantation for chronic myelogenous leukaemia.

Frequencies of human leucocyte antigens (HLA)-A, -B and -DR were determined in 751 patients with chronic myelogenous leukaemia (CML) reported to the European Group for Blood and Marrow Transplantation after bone marrow transplantation from HLA-identical family donors and related to the occurrence of graft-versus-host disease (GVHD). HLA-A3 and DR1 were significantly associated with acute GVHD, the first with a higher risk (44% in HLA-A3(+) versus 34% in HLA-A3(-) patients) and the latter with a lower risk (28% in HLA-DR1(+) versus 38% in HLA-DR1(-) patients) for developing acute GVHD grade II--IV. Both factors were independent of known variables for GVHD as shown in a multivariate analysis. The results show that MHC alleles independently influence the incidence of GVHD in bone marrow transplantation from an HLA-identical donor for first chronic-phase CML. Possible mechanisms might include an HLA antigen-specific allele-associated effect, and/or non-specific allele-associated immune hypo- or hyper-responsiveness.