TNF and irritable bowel syndrome: Some of these cytokines decrease the risk of IBS such as anti-inflammatory cytokines as IL-10 [20, 21], and some of them are found associated with the development of the IBS [22] such as pro-inflammatory cytokines, which always promote the inflammation response such as IL-1, IL-6, IL-8, IL-12, IL-18, and TNF-α, etc. [23–25].