Chronic lymphocytic leukaemia of T-cell origin. Immunological and clinical evaluation in eleven patients.

Eleven patients with chronic lymphocytic leukaemia of T-cell origin are reported. The identification of the leukaemic cells was performed with seven different membrane markers for either T or B lymphocytes. The reactivity of the leukaemic T cells with three different heteroantisera to T cells differed from patient to patient but was homogeneous in individual cases. This finding suggests that the leukaemic lymphocytes belonged to a single subset of T cells. These lymphocytes responded to allogeneic cells in some of these patients. In contrast, stimulation by non-specific mitogens was poor in most patients. Two patients were affected with the prolymphocytic type of chronic lymphocytic leukaemia, but a characteristic clinical and haematological pattern was found in nine patients. The blood and marrow infiltration was moderate and the proliferating T lymphocytes had a high content of lysosomal enymes in all patients and cytoplasmic granules in six cases. Other unusual features included massive splenomegaly (five patients), skin lesions (four patients), and major neutropenia (four patients).