Major histocompatibility complex class I presenting HA-1 and HA-2 minor histocompatibility antigens (MHC-I/mHag complex)

The MHC class I complex presenting HA-1 and HA-2 minor histocompatibility antigens (mHags) is a specialized immunological target used to treat hematologic malignancies following allogeneic stem cell transplantation. HA-1 and HA-2 are peptides derived from the ARHGAP45 and MYO1G proteins, respectively, which exhibit genetic polymorphisms between the transplant donor and recipient [1][2]. When presented by HLA-A*02:01 molecules, these peptides are recognized by CD8+ T cells as foreign, triggering a potent cytotoxic immune response [3]. Because the expression of HA-1 and HA-2 is largely restricted to the hematopoietic lineage, they serve as ideal targets for inducing a Graft-versus-Leukemia (GvL) effect while minimizing the risk of systemic Graft-versus-Host Disease (GvHD) [4]. Therapeutic interventions targeting these complexes include the development of T-cell receptor (TCR) engineered T cells and peptide-based vaccines aimed at eradicating residual leukemic cells [5]. Clinical application requires precise patient screening for both the HLA-A*02:01 allele and the specific mHag mismatch between donor and recipient [6].

Other names

Minor histocompatibility antigen HA-1Minor histocompatibility antigen HA-2HMHA1-HLA-A*02:01 complexMYO1G-HLA-A*02:01 complexmHag HA-1mHag HA-2ARHGAP45-HLA complexMYO1G-HLA complex

T-cell receptor (TCR) mediated recognition of the MHC-peptide complex leading to targeted lysis of hematopoietic cells.