Fig. 1. IL-19 and IL-20 mRNA and protein expression are synergistically induced by IL-17A and TNFα. Cultured human keratinocytes were stimulated with IL-17A (100 ng/ml), TNFα (10 ng/ml) or IL-17A combined with TNFα for 2, 6, 12, 24, or 48 hours (n=4). (A, B) IL-19 and IL-20 mRNA expression were analysed by qPCR, and RPLP0 was used as a reference gene for normalisation. (C, D) Protein expression was analysed by ELISA. IL: interleukin, TNFα: tumour necrosis factor alpha. ^*p<0.05 compared the synergistic effect against the additive effect for TNFα combined with IL-17A.