In experimental animal models, including DSS-induced colitis models, upregulation of mucosal addressing cell adhesion molecule 1 (MadCAM-1), a ligand for α4β7 integrin, a gut-homing molecule expressed in vessels in the colonic lamina propria of patients with IBD, suggests that improved interaction between α4β7 integrin and MadCAM-1 contributes to accelerating the influx of oral Th17 cells into the gut, with consequent aggravation of the intestinal pathology [91]. This evidence concerns the gene MADCAM1 and irritable bowel syndrome.