title: The membrane phenotype of T-prolymphocytic leukaemia.
abstract: Cells from 13 cases of T-prolymphocytic leukaemia (T-PLL) were studied with a battery of immunological techniques in order to define their membrane phenotype. All cases were E-rosette positive and were negative with OKT6, anti-HLA-DR, anti-Ig and M-rosettes; in 3, 20-30% of the cells had receptors for C3b. 7 cases had predominantly a 'helper/inducer' T-subset phenotype, (OKT4+, OKT8-) and 4 had a 'suppressor/cytotoxic' phenotype (OKT8+, OKT4-). Cells in 2 cases coexpressed OKT4 and OKT8 in 48% and 95% of prolymphocytes and in another, both OKT4 and OKT8 were negative. Terminal transferase (TdT) was negative by IF in all the cases, but a low positive level was detected biochemically in one. Although T-PLL appears to be heterogenous in respect of membrane phenotype, the observation of unexpected features in 8 of the cases raises the possibility that it may originate in a cell of intermediate maturation between late thymocytes and mature T-lymphocytes. These features plus the clinical manifestation of the disease - typical morphology, splenomegaly, lymphadenopathy, skin lesions, high WBC and aggressive clinical course - help define T-PLL as a distinct clinicopathological entity.
mesh_terms: D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006801:Humans; D007945:Leukemia, Lymphoid / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D011948:Receptors, Antigen, T-Cell / Q000032:analysis*; D012397:Rosette Formation; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell