Extra-Intestinal Manifestation of Helicobacter pylori Infection: Allergic Diseases Including Asthma, Atopy and Idiopathic Urticaria / 대한내과학회지

ABSTRACT

Helicobacter pylori (H. pylori) infection is known to be negatively associated with allergic diseases including asthma in epidemiologic studies, mainly from the western countries. Bronchial asthma and allergic diseases are initiated by T-cells producing T-helper type 2 (Th2) cytokines (e.g. interleukin-4 (IL-4) and IL-5), which is inhibited by Th1 responses. H. pylori infection appears to inhibit Th2 responses, as well as to drive Th1 inflammation, and recent studies using experimental models of allergic airway disease elucidated a direct link between H. pylori infection and suppression of allergic airway disease through the induction of regulatory T cells. H. pylori has been implicated as a factor in idiopathic urticaria. Its eradication, however, has been shown conflicting results only. Therefore, routine H. pylori eradication for patients with chronic urticaria is not recommended. In Korea, prevalence of H. pylori infection shows a decreasing trend, and studies on association of H. pylori infection with asthma is warranting in the population.