PCI-32765 induces selective cytotoxicity in CLL cells independent of IVGH mutational status or interphase cytogenetics. (A) CD19⁺ cells from CLL patients (N = 10) were incubated with or without increasing concentrations of PCI-32765 (0.01μM-100μM) for 48 hours. Viability was determined by MTT assay and was calculated relative to time-matched untreated controls. (B) CD19⁺ cells from CLL patients (N > 60) were incubated with or without PCI-32765 (0.1μM-10μM) for 48 hours. Viability was determined by annexin-V/PI flow cytometry. Dark lines represent averages. (C) CD19⁺ cells from CLL patients (N > 60) were incubated with or without 10μM PCI-32765 for 12-72 hours. Dark lines represent averages. (D) CD19⁺ cells from CLL patients (N > 60; minimum 10 per group) were incubated with or without 10μM PCI-32765 for 48 hours. Cytogenetics was determined independently of our laboratory. (E) CD19⁺ cells from CLL patients (N > 60; minimum 12 per group) were incubated with or without 10μM PCI-32765 for 48 hours. Mutational status was determined independently of our laboratory. In panels B through E viability was determined by annexin-V/PI flow cytometry, and was calculated relative to time-matched untreated controls.