TGFB1 and inflammatory bowel disease: In addition to the IL-17 isoforms, Th17 cells also differentiate and secrete other proinflammatory cytokines such as IL-6, IL-1β, TNF-α, IL-12, tumor growth factor (TGF)-β, IL-23, IL-21, IL-22, and IL-26 during the IBD pathogenesis [6].