Inverse correlation between allergy markers and Helicobacter pylori infection in children is associated with elevated levels of TGF-β.

OBJECTIVES: We evaluated allergy/hypersensitivity clinical markers and their correlation with Helicobactor pylori infection in children and adults to analyze how early acquisition of H. pylori could modulate allergic disorder expression.

PATIENTS AND METHODS: H. pylori presence was assessed by the rapid urease test and histology of antrum biopsies in 165 patients. Skin tests, serum IgE, and two clinical allergy questionnaires were performed. Allergy severity was operationally defined using a combined score. Findings were correlated with H. pylori status and cytotoxin-associated gene A presence in pediatric and adult patients. Transforming growth factor β (TGF-β) levels were measured by an enzyme-linked immunosorbent assay in serum and gastric biopsies of H. pylori (+) patients.

RESULTS: H. pylori (-) children had more positive skin tests to a higher number of antigens than H. pylori (+) children (P<0.05). Operationally defined allergy inversely correlates with H. pylori infection in children, but not in adults. The percentage of H. pylori infection was lower in children with severe allergy (32.3%) compared with children with mild allergy (43.4%) or no allergy (64.3%) (P<0.05). Colonization with virulent strains (cytotoxin-associated gene A+) showed a nonsignificant inverse correlation with severity of allergies in pediatric patients. H. pylori-infected children, but not adults, without allergy markers showed increased levels of TGF-β compared with allergic children both in serum and gastric mucosa (P<0.05).

CONCLUSION: There was a strong inverse correlation between allergy markers and H. pylori infection in pediatric patients associated with elevated levels of TGF-β locally and systemically. H. pylori-associated chronic gastritis might downregulate clinical allergy expression.