Action of anti-Fas IgM on viability of 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 nonviable cells was determined by flow cytometric analysis of PI-stained cells. Mean data for all isolates (inset). Bars represent standard errors of the means. No anti-Fas IgM (open bars). Plus anti-Fas IgM (hatched bars). Data were analyzed by Student t test. Percentages of apoptotic cells in drug-treated or irradiated samples were compared with those of the corresponding controls (*P > .05; **P < .05). For each incubation condition, percentage nonviable cells in the presence of anti-Fas were also compared with the corresponding percentages in the absence of anti-Fas (†P > .05)