Induction of apoptosis in lymphocytes from HIV-1–infected patients. Columns represent the percentages of apoptotic cells in untreated cells and cells cocultured with CH11, Fas-R triggering MoAb (N = 50). Statistical analysis shows the following relationships: in cultures of HIV-1⁺ lymphocytes: untreated v PHA-stimulated lymphocytes showed significantly increased numbers of apoptotic cells (P < .01); as was seen in study of untreated v CH11 MoAb-treated (P < .01); untreated v ZB4 MoAb-treated (P < .01); PHA-treated v PHA-treated cells + CH11 MoAb (P < .01). Normal HIV⁻ controls did not show statistically significant relationships (Wilcoxon two-sample test or one-sample test where appropriate).