T Cell Variant of Chronic Lymphocytic Leukaemia with Chromosome Abnormality and Defective Response to Mitogens

Abstract

Summary. Lymphocytes from a patient with chronic lymphocytic leukaemia, in whom therapy was ineffective, were defined as thymus-derived (T) cells by membrane markers (sheep erythrocyte rosettes, complement rosettes, surface immunoglobulin). The lymphocytes responded weakly to two mitogens, phyto-haemagglutinin and the calcium ionophore A23187, but not to concanavalin A. Cytogenetic studies of leukaemic cells from unstimulated and mitogen-stimulated cultures revealed an abnormal karyotype with 45 chromosomes and multiple rearrangements. The T cell variant of classical chronic lymphocytic leukaemia is relatively rare; additional reports are needed to determine if the clinical course is typically less benign than in the common B cell variety, or whether this patient simply represented a late, unresponsive phase of the disease.