TNF and irritable bowel syndrome: The pro‐inflammatory cytokine tumour necrosis factor α (TNFα) has been implicated in the development of peripheral sensitization and visceral pain in IBD and IBS patients, based on its causative role in inflammatory disease pathology, localized release from mast cells, and the significant correlation between pain scores and peripheral blood mononuclear cell (PBMC)‐evoked TNFα release in IBS patients (Hughes et al., 2013; Rijnierse et al., 2006).