Therapy of relapsed leukemia after allogeneic hematopoietic cell transplantation with T cells specific for minor histocompatibility antigens.

The adoptive transfer of donor T cells that recognize recipient minor histocompatibility antigens (mHAgs) is a potential strategy for preventing or treating leukemic relapse after allogeneic hematopoietic cell transplantation (HCT). A total of 7 patients with recurrent leukemia after major histocompatibility complex (MHC)-matched allogeneic HCT were treated with infusions of donor-derived, ex vivo-expanded CD8(+) cytotoxic T lymphocyte (CTL) clones specific for tissue-restricted recipient mHAgs. The safety of T-cell therapy, in vivo persistence of transferred CTLs, and disease response were assessed.

DDX3Y encodes a class I MHC-restricted H-Y antigen that is expressed in leukemic stem cells.

The Y chromosome encodes male-specific minor histocompatibility (H-Y) antigens that stimulate T- and B-lymphocyte responses after sex-mismatched allogeneic hematopoietic cell transplantation (HCT). A CD8(+) cytotoxic T lymphocyte (CTL) clone that recognizes a novel HLA-B*2705-restricted H-Y antigen encoded by the DDX3Y gene was isolated from a male who had received a hematopoietic cell graft from his human leukocyte antigen (HLA)-identical sister. The antigenic peptide is a decamer that differs from the homologous DDX3X-encoded peptide at 4 positions.