Current theories on the causes of inflammatory bowel disease

The understanding of the pathogenesis of Crohn's disease and ulcerative colitis has greatly expanded over the last decade. The combination of abnormalities in the immune system, the contribution of nonimmune cells in the intestinal mucosa, a variety of genetic risk determinants, and random environmental factors may all be necessary to induce what clinically presents as inflammatory bowel disease. It is likely that several agents can initiate an immune response that in the intestinal microenvironment and the genetic background of the patient finally leads to pathology.