Mucosal regulators and immunopathophysiology

Immunocompetent cells are present normally in the mucosa of the gut; their numbers increase during inflammatory conditions. When activated, these cells release potent chemical mediators or cytokines, which have the ability to induce intestinal pathophysiologic disorders. Activation can occur in response to a variety of stimuli, including specific antigens, noxious substances, or bacteria and their products. Neural involvement may amplify or inhibit the response. Exciting new evidence indicates that epithelial cells participate in immune and inflammatory reactions. This article reviews information reported in the past year about functional changes in the intestinal mucosa in response to immune mediators or activation of immune or inflammatory cells