title: Deficient expression of class-I HLA in some cases of acute leukemia.
abstract: Leukemic cells from the blood and marrow of 25 cases of newly diagnosed acute leukemia were presented as target cells to alloreactive effector cells from unrelated normal donors in cell-mediated cytotoxicity assays. In three cases the leukemic targets were poorly killed relative to nonleukemic, HLA-identical target cells. The poor killing of the leukemic cells from one of these cases was shown by competitive inhibition to be due to deficient expression of normal class-I HLA antigens rather than resistance to lysis. Furthermore, the leukemic cells from these three patients were also deficient in binding monoclonal antibodies to nonpolymorphic determinants of class-I HLA and B2 microglobulin. Two additional cases were identified as having a less extensive deficit of HLA, and may be representative of a group with relatively subtle changes in these cell surface antigens. The possible significance of reduced expression of HLA in leukemic progression and in susceptibility to graft-vs-leukemia reactions after bone marrow transplantation is discussed.
mesh_terms: D000208:Acute Disease; D001853:Bone Marrow / Q000276:immunology; D002478:Cells, Cultured; D002648:Child; D003602:Cytotoxicity, Immunologic; D005455:Fluorescent Antibody Technique; D006680:HLA Antigens / Q000032:analysis*; D006801:Humans; D007938:Leukemia / Q000276:immunology* / Q000473:pathology; D007945:Leukemia, Lymphoid / Q000276:immunology*; D015470:Leukemia, Myeloid, Acute / Q000276:immunology*; D007959:Lymphocyte Culture Test, Mixed
chemical_list: D006680:HLA Antigens