P2X7 receptor expression in evolutive and indolent forms of chronic B lymphocytic leukemia

Human leukocytes express a receptor for extracellular nucleotides, named P2X(7)R, that in lymphocytes can either mediate cell death or proliferation, depending on the level of activation. The authors have investigated P2X(7)R expression and function in 21 patients affected by B-cell chronic lymphocytic leukemia, 13 with an evolutive and 8 with an indolent variant of the disease. Resting cytoplasmic Ca++ concentration was significantly higher in lymphocytes from patients with the evolutive compared with indolent variant. Furthermore, in the former, P2X(7)R stimulation triggered a Ca++ Influx significantly larger. Higher Ca++ influx correlated with an increased P2X(7)R expression in the lymphocytes from patients with the evolutive form. Finally, incubation in the presence of extracellular adenosine triphosphate decreased spontaneous proliferation of lymphocytes from patients affected with the evolutive variant but had no effects on lymphocytes from patients with the indolent form. These results suggest that expression and function of P2X(7)R may correlate with the severity of B-cell chronic lymphocytic leukemia. (Blood. 2002;99:706-708) (C) 2002 by The American Society of Hematology.