Interaction between interleukin-17-producing CD4+ T cells and colonic subepithelial myofibroblasts: what are they doing in mucosal inflammation?

Recent studies have shown alterations and activations in the mucosal immune system in patients with irritable bowel syndrome (IBS) as well as in those with inflammatory bowel disease (IBD). As one of effectors of mucosal inflammation, a new lineage of effector CD4+ T cells characterized by production of interleukin (IL)-17, the T-helper (Th)-17 lineage, was recently described. Th-17 cells are developmentally and functionally distinct from Th1 and Th2 cells. Here, we discuss the recent concept of low-grade inflammation as a factor associated with the pathophysiology of IBS. Furthermore, based on the data from our laboratory, interaction between Th-17 cells and colonic subepithelial myofibroblasts may play an important role in the pathophysiology of IBS and IBD.