Delayed CLL disease progression by PCI-32765 in TCL1 model. (A) Peripheral blood (100 μL) from mice treated with control vehicle (n = 4), 2.5 (n = 3), or 25 mg/kg/d (n = 4) PCI-32765 were incubated with B220 and CD5 antibodies. Numbers of CLL cells were determined using calibrated counting beads. Results shown are the mean CLL cell counts ± SD with RMANOVA statistic analysis on control versus treated mice. *P < .01, ***P < .0001. (B) All 11 mice were killed 16 days after treatment. Top: example of each group of mice after 16 days of treatment. Spleen (middle) and liver (bottom) tissue sections were assessed histologically after H&E staining. Less lymphocyte infiltration was observed in 25 mg/kg/d PCI-32765 treated mice compared with control mice. (C) Spleens from control or PCI-32765 treated mice were compared for size and weight. The right panel shows the mean spleen weight ± SD with the unpaired t test on control versus treated mice. *P < .05. (D) Spleen cells from mice treated for 16 days with vehicle or PCI-32765 were left untreated (−) or treated with 25μM pervanadate (PVD) for 4 minutes (+). Intracellular staining of phosphorylated PLCγ2 (pPLCγ2) was then performed and analyzed by flow cytometry on gated B220⁺CD5⁺ cells. Results are the mean fluorescence intensity (MFI) of phosphorylated-PLCγ2 ± SD with the unpaired t test on control versus treated mice. *P < .05.