Colonization with IBD microbiota induced more Th17 cells and a population of highly pro-inflammatory T cells co-expressing the cytokines IL-17 and IFN-γ.[29] Regulation of these cytokines is generally mediated by the immunoregulatory cytokine, such as IL-10 or TGF-β produced by Tregs [30]. Here, IL17A is linked to inflammatory bowel disease.