Cytokines in inflammatory bowel disease.

Inflammatory bowel diseases are chronic afflictions, characterized by active and remission periods. Inflammation is the most common type of response that the human body uses as a defense mechanism against aggressors from the environment. The frequency and degree of inflammation depends on the size of the affected tissues. The gastrointestinal tract is, by far, the most susceptible tissue to inflammatory responses, because of its constant exposure to various antigenic, mutagenic and toxic factors. In inflammatory bowel diseases there is a loss of immune tolerance to intestinal flora that is mediated by various substances, including cytokines. Cytokines represent a key signal in the intestinal immune response. Activated dendritic cells and macrophages secrete cytokines that actively intervene in inflammation regulation, in both Crohn's disease and ulcerative colitis. After their secretion by antigen presented cells, cytokines activate and differentiate T cells, stirring up the adaptive immune response. Cytokines have an important role in the pathogenesis of inflammatory bowel diseases. The identification of new cytokines, as well as the changing of the pathogenesis paradigms in inflammatory bowel diseases has been done on animal tests and clinical studies. Thus, there is promising evidence basis for future therapy research based on cytokines, and anti-cytokine antibodies.