TNF and irritable bowel syndrome: They emphasized that mast cells are activated early in the pathogenesis of both diseases, resulting in the production of pro-inflammatory cytokines, such as interleukins (IL-1 beta, IL-8, IL-6, and IL-17) and tumor necrosis factor alpha (TNF-α), which affect the intestinal mucosa in IBS patients, while their systemic impact may cause widespread body pain in FM patients.