Can it control gluten sensitivity and asthma?
Helicobacter pylori infection is no laughing matter. Sufferers can look forward to such unpleasant symptoms as chronic gastritis, gastric ulcers, and possibly gastric adenocarcinoma. Only discovered in 1982, H. pylori‘s pervasive presence, particularly in developing countries, is now accepted as the underlying cause of many gastric disorders.Despite the undeniably negative effects of H. pylori colonization, deeper analyses of patient populations are revealing surprising correlations between incidence of the bacterium and immune system effects. For some patients without acute effects, elimination of H. pylori may actually be detrimental.
Epidemiologic investigation of H. pylori‘s connection to other conditions usually begins with noting the extreme disparity in rates of H. pylori colonization between the developed and developing world, and then examining a correlated condition for actual connection to the bacterium.
In 2011, Arnold et al designed a study to determine whether the strong negative correlation between allergic asthma and H. pylori colonization indicated an underlying connection between the two. Using mice, the researchers deliberately infected infant and adult mice with H. pylori,and kept a control group for both ages. The researchers induced allergic asthma in both groups and measured their immune response. Mice with H. pylori infection displayed a significantly reduced asthmatic response by several metrics, including bronchoalveolar inflammation,eosinophilia, IL-5 secretion, and IL-13 secretion. 
The connection between digestive infection and a digestive disorder makes for a more intuitive link. Coeliac disease is an autoimmune condition that most visibly involves a reaction to gluten, a protein found in some cereal grains. Although the precise cause of coeliac diseases is still unclear, multiple reviews have found statistically significant negative correlations between H. pylori colonization and coeliac disease, in various patient populations. [2,3]
The proposed mechanism of action is the same as in the protective effect against allergic asthma; H.pylori infection results in additional recruitment of T-regulatory lymphocytes. These additional recruited cells then down regulate the immune response to gluten,compensating for the out-of-proportion response typical of coeliac disease. 
If evidence for a benefit from H. pylori colonization continues to appear, physicians could face an interesting choice. In a 2012 paper, Melo et al reported that the gastric mucosa of children infected with H.pylori show significantly higher expression of immunologic cells and factors than uninfected children.  The bacterium can usually be eliminated simply enough with an antibiotic regimen, but for some patient populations the benefits could outweigh the risks if acute symptoms haven’t yet occurred.
The potential benefits of an upregulated immune system to stave off chronic allergic conditions deserve further consideration and research.
By Weston Mangin