Inflammatory bowel disease: Etiology and pathogenesis

The field of gastroenterology offers many challenges to both the clinician and the investigator, but few are as complex and enigmatic as inflammatory bowel disease (IBD). Crohn’s disease (CD) and ulcerative colitis (UC) have been known for well over one half a century, but why affected individuals spend their lives with a chronic inflammatory process that relentlessly destroys their bowel remains a mystery. Advances, although unequal in different areas, have been plentiful in the last decade when the combined power of cellular and molecular biology began to unveil the enigmas of IBD. No single agent or distinct mechanism is the sine qua non motive that explains all aspects of IBD, and several distinguishing factors are likely necessary to result in either CD or UC (Table 1). This review will attempt to discuss those that currently appear important.