BCR triggering promotes PLCγ2 phosphorylation and calcium mobilization in responding CLL B cells. (A) Phospho-Y759-PLCγ2 levels were analyzed using a specific PE-coupled antibody in CLL B cells (CD20⁺/CD5⁺/CD3⁻) by flow cytometry analysis. Histogram plots show pY759 PLCγ2 MFI in unstimulated (α-IgM⁻, top) and stimulated (α-IgM⁺, bottom) B cells from 1 representative patient for each CLL group (NR, left; R, right). Phospho-PLCγ2 was measured for 43 samples after 10 minutes of incubation with anti-IgM antibody in NR (n = 20, black dots) and R (n = 23, black squares) cases, calculated as fold induction over unstimulated cells and graphed. (B) Calcium release curves established in NR (n = 7, left) and R (n = 8, right) cases. After 60-second stabilization, CLL B cells were stimulated with anti-IgM antibody (+ α-IgM) followed at 290 seconds by ionomycin addition (+ ionomycin).