The observation that targeting IL-23 (a key cytokine in Th17 cell development) with a p40 peptide-based vaccine ameliorates chronic TNBS-induced colitis,and reduces IL-17A, TGF-β1 levels, and collagen deposition in the bowel wall [25], highlights the importance of IL-17A in intestinal experimental fibrosis. The gene discussed is IL17A; the disease is colitis.