Current views of the etiology of inflammatory bowel disease

The cause or causes of Crohn's disease and of ulcerative colitis (UC) remain uncertain. Despite extensive investigations aimed at searching for immunologic or infectious causes, clear evidence suggesting an underlying etiology is lacking. Recent studies involving mycobacteria suggest that occasional patients thought to have Crohn's disease may indeed be infected with a mycobacterium. However, clear cause-and-effect relationships have not been established. Future efforts to establish the relationship between environmental factors, including infectious agents, and immunologic mediators seem appropriate on the basis of available data. For the present, the causes or cause of these diseases remains obscure.