Omalizumab reduced proliferating mIgE+ B cells. B cells were labeled with 2.5 μM CFSE prior to treatment with IL-4 + anti-CD40 in the presence or absence of 1 μg/mL omalizumab (Om). After 3 days the cells were stained with APC conjugated anti-human IgE and analyzed by flow cytometry (A) for the number of proliferating cells (B) and the number of proliferating mIgE+ cells (C). Panel A: Representative experiment of 4 independent experiments. NT: non-treated cells. Panels B and C: Data are expressed as the mean ± SEM from 4 separate independent experiments (4 tonsils). Statistically significant difference (p value) was determined by t-test.