Sildenafil-induced apoptosis in B-CLL cells is prevented by IL-4 and SDF-1α but not by autologous plasma.

(A) B-CLL lymphocytes (n = 3) were cultured for 24 hours with or without sildenafil (50 μg/mL) in the absence or presence of either IL-4 (20 ng/mL) or SDF-1α (1 μg/mL). (B) Cultures were performed in RPMI supplemented with 10% FCS or 1% autologous plasma. Percentages of dead cells (annexin⁺ cells) were determined as described in the legend to Figure 1.