Could Helicobacter organisms cause inflammatory bowel disease?

Robin Warren and Barry Marshall deservedly won the Nobel Prize for medicine in 2005 for their groundbreaking discovery that Helicobacter pylori was the infectious agent underpinning gastric and duodenal ulceration. This discovery transformed the management of two chronic conditions from maintenance symptomatic therapies, and in some cases surgery, to curative treatment with targeted antibiotics. The possibility that infections by other organisms from the genus Helicobacter are the pathogenic mechanism behind other human diseases is a tantalising one. The inflammatory bowel diseases (IBD): Crohn’s disease (CD) and ulcerative colitis (UC) demonstrate many similarities to gastric and duodenal ulceration before the discovery of H. pylori, including unexplained onset in previously healthy hosts, a chronic disease course with no curative treatments, chronic gastrointestinal inflammation and predisposition to malignant change. In this review article, we shall consider the evidence supporting Helicobacter organisms as pathogenic agents in IBD. We will discuss the relative incompatibility of H. pylori disease and IBD, highlighted by the apparent protective effect of prior H. pylori infection on IBD disease risk. We shall review animal variants of IBD which are both initiated by and associated with Helicobacter infection. We will then review the Helicobacter organisms associated with human gastrointestinal disease and the molecular evidence for Helicobacter organisms in human IBD. For the purpose of clarity, Helicobacter organisms associated primarily with gastritis or biliary disease are not covered within this article.