Minor histocompatibility antigens: from T cell recognition to peptide identification.

BACKGROUND Bone marrow transplantation (BMT) in combination with chemoradiotherapy is used as treatment of severe aplastic anemia, leukemia, and other hematologic malignancies The ideal transplant Situation is when BM donor and recipient have identical MHC antigens and are closely related Nonetheless, the results of clinical BMT reveal that the selection of MHC-identical donors is not a guarantee of avoidance of two of the major drawbacks of allogeneic BMT, ι e , graft-versus-host disease (GvHD) and leukemia relapse GvHD occurs, depending on the age of recipient and the amount of Τ cell depletion of the graft, in 15—35% of the HLA genotypically identical donoi/recipient situations [1,2] Τ cell depletion of the donor marrow moculum shows a reduction in the incidence and seventy of GvHD but coincides with an increase of leukemia relapse On the one hand, mature Τ cells present in the donor bone marrow inoculum are essential for graR acceptance, on the other hand, they are responsible for GvHD but most probably also cause the