MONOCLONAL EXPANSION OF IMMUNOGLOBULIN NOT-SECRETING CD5-CELLS IN A RARE CASE OF CHRONIC LYMPHOPLASMACYTOID LEUKEMIA( CD11C+ CD38+ B)

We present the clinical and immunological features of a rare case of c hronic lymphoid leukaemia with lymphoplasmocytoid morphology. The pati ent was first admitted suffering from weakness, pallor, dyspnoea, mark ed splenomegaly, hepatomegaly and systemic lymphadenopathy and panhypo gammaglobulinaemia. White blood cell count revealed important leukocyt osis (220 x 10(9) WBC/l) with 2% neutrophils and 98% lymphoid cells sh owing lymphoplasmacytoid features, while lymphoid cells of identical m orphology severely infiltrated the bone marrow and lymph nodes. The di sease, initially controlled by non aggressive chemotherapy over a peri od of 30 months, later evolved to a clinical and haematological pictur e suggestive of Richter's syndrome. Immunophenotyping of the leukaemic cells demonstrated a monoclonal expansion of B-cells bearing surface markers of typical CLL (CD5, CD19, CD20, CD21, CD22, CD23, CD24, CD40 and low density IgM+IgD/kappa) and also the CD11c and CD38 antigens. A proportion of these cells expressed activation markers (CD25, CD69 an d CD71). Following in vitro activation with TPA or PWM, the cells resp onded by weak incorporation of 3H-TdR but failed to secrete immunoglob ulins. These findings confirm the broad morphological, phenotypical an d clinical spectrum of chronic lymphoid leukaemias.