Inflammatory Bowel Diseases: Pathogenesis

The two main forms of inflammatory bowel disease (IBD) are Crohn's disease and ulcerative colitis. The past decade has seen substantial advances in our understanding of the pathogenesis of IBD, and in particular the complex interaction with functional alternations in the immune system. IBD is caused by interaction between dysbiosis in the intestinal microbial community, maintenance of the intestinal barrier, and the immune system. Alterations in the host genetics and environment results in chronic inflammation in inflammatory bowel diseases. Recent research has highlighted, in particular, the critical role of the innate immune response in the pathogenesis of IBD, supported by the co occurrence of IBD in patients with primary immunodeficiency states associated with defective innate immune mechanisms. Much of the focus on the role of the adaptive immune response in IBD has been directed on CD4+ T-helper cells (Th cells).