Figure 4.

Effects of ibrutinib on expression of activation‐linked cell surface antigens on human blood basophils. Basophils (BA) obtained from three nonallergic donors (A), three patients allergic to Der p 2 (B), and three allergic to Phl p 5 (C) were preincubated in control medium (Co) or in medium containing various concentrations of ibrutinib (0.001‐10 μmol/L) at 37°C for 30 minutes. Then, cells were exposed to anti‐IgE antibody E‐124.2.8 (1 μg/mL; healthy donors) or recombinant allergens (1 μg/mL of rDer p 2 or rPhl p 5; allergic patients) for another 15 minutes (37°C). Thereafter, cells were stained with monoclonal antibodies against CD13, CD63, CD164, or CD203c and analyzed by multicolor flow cytometry as described in the text. BA were defined as CD203c⁺ cells. Anti‐IgE‐ or allergen‐induced upregulation of CD antigens was determined from mean fluorescence intensities (MFI) obtained with stimulated (MFIstim) and unstimulated (MFIcontrol) cells and expressed as stimulation index (SI=MFIstim: MFIcontrol). Results show SI values and represent the mean±SD from three donors in each experiment. Asterisk (*): P<0.05 by Student's t test with Bonferroni correction