IL17A and inflammatory bowel disease: In IBD, there is a markedly increased local production of various nonspecific inflammatory mediators, such as free radicals, leukotrienes, chemokines, and proinflammatory cytokines (e.g., TNF and TNF-related cytokines and IL-6 family of cytokines: IL-12, IL-23, IL-17, IL-18, and TGF-β) which follow the influx of inflammatory cells into the intestinal tissue [10].