More than half the people in the world are infected with H. pylori, although it is very unusual to find it in the United States. But this research shows there may be an inflammation control benefit to hosting the H. pylori infection, says Peter Higgins, lead author of the study.
"If we have evolved to live with certain bugs, maybe there is a reason," said Higgins, assistant professor of gastroenterology in U-M's Department of Internal Medicine.
"This research demonstrates that having H. pylori in your stomach could have beneficial immune effects in other parts of the body."
In the study, mice were infected with H. pylori, allowed to develop immune tolerance for a month, and then infected with Salmonella, which induces the inflammatory bowel disease colitis. The data provided the first evidence that H. pylori infection in the stomach alters the immunological environment of the lower gastrointestinal tract and reduced the severity of Salmonella-induced colitis.
"This was surprising because H. pylori infects the stomach, not the colon. It appears to have a more global effect on the gut immune system," says John Kao, senior author of this study and assistant professor in U-M's Department of Internal Medicine.
"But it may explain why people in regions with lots of H. pylori infection - such as Asia and Africa - get fewer inflammatory bowel diseases, like ulcerative colitis and Crohn's disease."
The study has been published in the journal Inflammatory Bowel Diseases.