Differential effect of MDM2 antagonists on B and T cells. Dose response of the cytotoxic effect of MDM2 antagonist nutlin-3a on B and T cells from B-CLL patients (A) or healthy donors (B). Cells were incubated with a range of doses of nutlin-3a (up to 10 μM) for 48 hours. Viability was measured as nonapoptotic CD3⁺/CD19^–T cells (○, □) or CD3^–/CD19⁺ B cells (•, ▪) as described in “Patients, materials, and methods” and expressed as the percentage of the viability of untreated cells. Data are shown as the mean value ± SD of 6 B-CLL patients (A) and 7 healthy donors (B). *P < .05 B cells versus T cells.