Abrogation of signaling downstream of the BCRs and of CXCR4 and CXCR5 receptors. Displayed are immunoblots from CLL cells from 1 representative patient of 9 patients, that were either unstimulated or stimulated for 10 minutes with anti-IgM (αIgM, left row), CXCL12 (middle row), or CXCL13 (right row) in the presence or absence of PCI-32765 as indicated. P indicates immunoblotting for the active, phosphorylated form, whereas T represents the nonphosphorylated, total amount of the respective proteins.