IDENTIFICATION OF A GRAFT-VERSUS-HOST DISEASE-ASSOCIATED HUMAN MINOR HISTOCOMPATIBILITY ANTIGEN

Minor histocompatibility antigen disparities between human leukocyte a ntigen (HLA)-matched bone marrow donors and recipients are a major ris k factor for graft versus host disease (GVHD). An HLA-A2.1-restricted cytotoxic T cell clone that recognized the minor histocompatibility an tigen HA-2 was previously isolated from a patient with severe GVHD aft er HLA-identical bone marrow transplantation. The HLA-A2.1-bound pepti de representing HA-2 has now been identified. This peptide appears to originate from a member of the non-filament-forming class I myosin fam ily. Because HA-2 has a phenotype frequency of 95 percent in the HLA-A 2.1-positive population, it is a candidate for immunotherapeutic inter vention in bone marrow transplantation.