Interleukin-17 are the major cytokine in chronic gastritis induced by Helicobacter pylori infection.

Helicobacter pylori (H. pylori ) is a highly prevalent bacteria directly involved in various diseases of the upper digestive tract such as gastritis, peptic ulcer and gastric cancer. In this study we analyze in situ immune response in gastric biopsies obtained during endoscopic procedures from 49 patients. Quantitative PCR were performed on cDNA copies of total RNA extracted from each biopsies. PCR were done using Taqman system to selected cytokines and cytokines transcriptions factor representative of Th1, Th2, Treg and Th17 lymphocytes. The relative number of mRNA copies were adjusted using the beta actin gene. The analysis were performed on samples grouped according to presence or absence of H. pylori infection. No significant difference was found in the expression of IFN-γ, IL-4 and IL-10 when comparisons were done between patients with and without H. pylori infection. Moreover, no difference was observed in the expression of T-bet, GATA-3 and FoxP3. On the other hand, the levels of IL-17 and ROR-gamma T were significantly higher in samples obtained from patients with H. pylori infection, compared with those from non infected. The results presented here suggest that IL-17 are involved in the chronic inflammatory process induced by H. pylori.