Irritable Bowel Syndrome and Immune Activation

Irritable bowel syndrome (IBS) is a highly prevalent functional gastrointestinal disorder characterized by chronic abdominal pain and bowel habit change. Its specific pathophysiologic mechanism underlying IBS is not known; however, it is generally accepted that IBS symptoms represent dysregulation at multiple levels of the brain-gut axis. IBS symptoms are manifested by abnormal motor reactivity to various stimuli, and low sensation and pain thresholds. Recently, a variety of new findings have been reported which suggests low-grade inflammation or immune activation is present in IBS patients, including post-infectious IBS. The immune activation can generate various symptoms such as abdominal pain, bloating, and diarrhea that may result from motor dysfunction and visceral hypersensitivity. Anti-inflammatory therapy with either antibiotics or probiotics seems to be effective in reducing the symptoms of IBS. While this pathophysiologic approach to the management of IBS is in its infancy, it is evident that the immune activation deserves further attention in IBS.