Action of anti-Fas IgM on apoptosis induction in B-CLL cells.

B-CLL cells were treated with cytotoxic agents in the presence or absence of 50 ng/mL anti-Fas IgM as indicated. Percentage of apoptotic cells was determined by morphologic criteria. Lines connect data points obtained using individual B-CLL isolates. Standard errors of individual determinations were less than 10% of the mean values reported. Mean data for all isolates (inset). No anti-Fas IgM (open bars). Plus anti-Fas IgM (hatched bars). Bars represent standard errors of the means. Data were analyzed by Student t test. Percentages of apoptotic cells in drug-treated or irradiated samples were compared with those of corresponding controls (**P < .05). For each incubation condition, percentage apoptotic cells in the presence of anti-Fas were also compared with the corresponding percentages in the absence of anti-Fas (†P > .05).