Time-dependent effects of IL-4, IL-13 and IFN-γ on IL-13Rα1 (A), IL-4Rα (B) and IL-13Rα2 (C) mRNA expression. HASM were incubated with vehicle, IL-4 (5 ng/ml), IL-13 (5 ng/ml) or IFN-γ (10 ng/ml) for 3, 6, 12 and 24 hours. Receptor subtype and 18S mRNA expression was quantified using real-time PCR. Data are expressed as the relative expression in receptor subtype/18S mRNA ratio and compared to unstimulated (vehicle) value of 1 at time 0, for five independent experiments. * p < 0.05 compared to cells treated with vehicle (ANOVA).