News Life How a stomach bug may ward off asthma H. pylori’s influence on immune system could reduce airway disease By Tina Hesman Saey February 8, 2012 at 11:02 am - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Click to share on Facebook (Opens in new window) Facebook Click to share on Reddit (Opens in new window) Reddit Click to share on X (Opens in new window) X Click to print (Opens in new window) Print A bacterium that causes ulcers and stomach cancers may protect against asthma by teaching the immune system tolerance, a new study in mice shows. Stomach cancer cases have dropped in North America and Europe as the number of people who carry the bacterium Helicobacter pylori has declined.