TNF and ulcerative colitis: In the mucosa of Crohn’s disease and ulcerative colitis patients, there is an increase in the mucosal macrophage population derived from circulating monocytes; these cells have the ability to produce many mediators that are important in the proinflammatory responses, such as IL-1, IL-6, TNF-α, reactive metabolites of oxygen and nitrogen and proteases, and the expression of iNOS (34–38).