title: Acute leukemia of hybrid phenotype: T lymphoid and myelomonocytic markers.
abstract: Several unique phenotypical and functional characteristics were found together in a patient with acute poorly differentiated leukemia. The blast cells showed an unusual T-cell phenotype, forming spontaneous rosettes with sheep red blood cells and expressing the T11 antigen, but were negative for the other immature or mature T markers tested--Leu-1, 3A1, T3, T4, T8, T9, T10, T6, and TdT--and reacted with the monoclonal antibody OKM1 expressed by myeloid lineage cells and which is also present in natural killer (NK) cells. Furthermore, these cells were able to produce interleukin-2 (IL-2) after mitogenic stimulation and showed cytotoxic activity against K-562 target cells after incubation with an IL-2 supernatant. These features do not correspond to any known stage of the T-cell differentiation pathway and may represent the expansion of a pre-NK cell which may be poorly represented in normal tissues.
mesh_terms: D000208:Acute Disease; D000954:Antigens, Surface / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D006822:Hybrid Cells; D007376:Interleukin-2 / Q000096:biosynthesis; D007694:Killer Cells, Natural; D007938:Leukemia / Q000473:pathology*; D015470:Leukemia, Myeloid, Acute / Q000473:pathology; D010641:Phenotype; D013601:T-Lymphocytes / Q000473:pathology*
chemical_list: D000954:Antigens, Surface; D007376:Interleukin-2