[Role of cytokines in the pathogenesis of gastrointestinal diseases associated with Helicobacter pylori infection].

It is well known that Helicobacter pylori can cause gastritis, gastroduodenal ulcers and malignant diseases. The infiltration of polymorphonuclear leukocytes is recognized in the lesions of these diseases, and the infiltration disappears by antibiotic therapy. However, it is not yet clarified how Helicobacter pylori induces the formation of lesions including leukocyte infiltration. Recently, we have confirmed that several kinds of cytokines are expressed in the gastric biopsy specimens of gastroduodenal diseases. Especially, it is conjectured that chemokines such as interleukin-8 (IL-8) which are expressed in the specimens, induce leukocyte infiltration, gastric mucosal inflammation and gastroduodenal ulcers. It is possible that Helicobacter pylori CagA gene is closely related with IL-8 expression because this cytokine is more strongly expressed in the specimens from the patients infected with CagA-positive Helicobacter than those with CagA-negative one.