T-CELL-SUBSET CHARACTERIZATION OF HUMAN T-CLL

Abstract

Circulating peripheral blood tumor cells in 4 cases of chronic lymphoproliferative disease were immunologically characterized. By the use of T [thymus-derived] cell-specific heteroantisera and indirect immunofluorescence, all involve proliferation of malignant T cells. Three cases demonstrated morphologic and clinical features consistent with chronic lymphocytic leukemia (CLL), and 1 case presented as a lymphosarcoma cell leukemia. Antisera specific for normal human T cell subsets defined the malignant T cells in each case as arising from the TH2- subset. This subset normally constitutes approximately 80% of human peripheral blood T cells. Terminal deoxynucleotidyl transferase (TdT) was not detected in any of the T cell CLL cases, supporting the notion that T cell CLL represents a malignancy of a mature phenotype. The 1 patient with lymphosarcoma whose tumor cells were TdT-positive subsequently developed T cell acute lymphoblastic leukemia (ALL). Ia-like antigen (p23,30) was detected on 2 of these tumor cell populations. Not all tumor cells were E[erythrocyte]-rosette-positive, since only cells from 3 of 4 patients were capable of forming spontaneous rosettes. Heteroantisera can provide an additional important tool for dissecting the heterogeneity of T cell leukemias and for relating them to more differentiated normal T cells.