Impact of disparity of minor histocompatibility antigens HA-1, CD31, and CD49B in hematopoietic stem cell transplantation of patients with chronic myeloid leukemia with sibling and unrelated donors

Despite human leukocyte antigen (HLA) identity between donor and recipient, several patients develop acute graft-versus-host disease (aGVHD) after hematopoetic stem cell transplantation (HSCT) because of minor histocompatibility antigen (mHag) incompatibilities. The impact of multiple mHag disparities on the clinical outcome after HSCT still remains to be determined. We studied the genomic polymorphisms of HA-1, CD31, and CD49b and correlated mHag distribution with the occurrence of aGVHD after HSCT from HLA-matched sibling and unrelated donors. All 163 patients examined in our single-center study underwent HSCT for chronic myeloid leukemia in the first chronic phase. HA-1 and CD31 disparities are associated with increased aGVHD incidence in a subgroup of patients who test HLA-B44 supertype positive in univariate analysis. However, in a multivariate analysis, only increased patient age was confirmed as an independent aGVHD risk factor. Our findings indicate that the impact of mHag disparity on aGVHD development in HSCT from HLA-matched sibling and unrelated donors seems to be subordinated to classic aGVHD risk factors.