Human skin mast cells were sensitized with anti-NP IgE, pre-treated with IL-6 at 1, 10, or 100 ng/ml for 1 h, and then challenged with NP-BSA (100 ng/ml) for 24 h. Secreted VEGF (A, C), IL-8 (D) and TNF (E) in cell-free media were measured with ELISA. (B) IL-6-induced VEGF mRNA expression was analyzed by quantitative real-time PCR using total RNA isolated from mast cells treated with IL-6 (100 ng/ml) for 1, 3, 6, 12, and 24 h. >2-fold change was considered significant. (C) C188-9 inhibits IL-6-induced VEGF production. Bars represent mean ± S.E.M. of values from 3 separate experiments with mast cells from different donors. Significance was determined by ANOVA. *, p<0.05, **, p<0.01, ***, p<0.001, #, p<0.0001.