Innate Immunity Components and Cytokines in Gastric Mucosa in Children withHelicobacter pyloriInfection

Abstract

Purpose.To investigate the expression of innate immunity components and cytokines in the gastric mucosa amongH. pyloriinfected and uninfected children.Materials and Methods.Biopsies of the antral gastric mucosa from children with dyspeptic symptoms were evaluated. Gene expressions of innate immunity receptors and cytokines were measured by quantitative real-time PCR. The protein expression of selected molecules was tested by immunohistochemistry.Results. H. pyloriinfection did not lead to a significant upregulation ofMyD88, TLR2, TLR4, CD14, TREM1,andTREM2mRNA expression but instead resulted in high mRNA expression ofIL-6, IL-10, IFN-γ, TNF-α,andCD163. H. pylori cagA(+) infection was associated with higherIL-6andIL-10mRNA expression, as compared tocagA(−) strains.H. pyloriinfected children showed increased IFN-γand TNF-αprotein levels. IFN-γmRNA expression correlated with bothH. pyloridensity of colonization and lymphocytic infiltration in the gastric mucosa, whereas TNF-αprotein expression correlated with bacterial density.Conclusion. H. pyloriinfection in children was characterized by (a) Th1 expression profile, (b) lack of mRNA overexpression of natural immunity receptors, and (c) strong anti-inflammatory activities in the gastric mucosa, possibly resulting from increased activity of anti-inflammatory M2 macrophages. This may explain the mildly inflammatory gastric inflammation often observed amongH. pyloriinfected children.