Bar plots showing LAMP-1 expression (A) and histamine release (B) by human mast cells following sensitization with IgE, treatment with drug vehicle (DMSO) or omeprazole, and challenge with anti-IgE for 10 and 5 minutes, respectively. Secretion of PGD2 (C), IL-5 (D) and IL-13 (E) by IgE-sensitized human mast cells following omeprazole treatment and stimulation with anti-IgE for six hours. Statistical analysis by one-way analysis of variance. *P<0.05, **P<0.01, ***P<0.001, and ****P<0.0001.