Additive effect of drugs and irradiation on apoptosis of B-CLL cells and CYC202-induced apoptosis in normal lymphocytes. (A) Apoptosis in B-CLL cells analyzed by annexin V assay at 0, 24, 48, and 72 hours of treatment with either 20 μM fludarabine (n = 25) or 5 μg/mL CYC202 (n = 21), with or without 5 Gy ionizing radiation (IR). ♦ and bold solid line indicate CYC202 alone; ▪ and thin solid line, fludarabine alone; ▴ and dashed line, fludarabine plus IR; and • and dotted line, CYC202 plus IR. (B) Effects of incubation with 5 μg/mL CYC202 on apoptosis of normal B cells (▴ and dotted line), normal T cells (♦ and bold solid line), and B-CLL cells (▪ and thin solid line). Graphs represent mean proportion of apoptotic cells at each time point, and error bars represent 95% confidence intervals.