Antileukemic activity of BL22 in combination with chemotherapeutic anticancer agents. B-CLL cells were cultured for 72 hours at indicated concentrations of anticancer drugs with or without 1000 ng/mL BL22. Apoptosis induction was assessed using Annexin V/PI staining, as described in “Patients, materials, and methods.” Numbers of analyzed patient samples are indicated. Results are presented as means ± SEM. Paired t test was performed for comparison of apoptosis induction by BL22 in the presence or absence of chemotherapeutic anticancer drugs. Significance levels are indicated: ^*P < .05; ^**P < .01; NS indicates not significant (P > .05).