Several cytokines that are elevated in patients with IBD are known to activate STAT3 and or its downstream targets, including IL-6, IL-15, IL-21, IL-23, IL-17, IL-18, IL-10, IL-11, IL-22, IFNα/β /γ and matrix metallopeptidase 9 (MMP9) [101,102,103,104,105,106,107,108,109]. Here, IL17A is linked to inflammatory bowel disease.