FOXP3+ Regulatory T Cells in Children with Helicobacter Pylori Infection

Despite an intensive pro-inflammatory response, the immune system is unable to clear the organism in Helicobacter pylori gastritis. Regulatory T (Treg) cells, which suppress the immune response of antigen-specific T cells, have recently been demonstrated to play a key role in chronic inflammation by immunologic tolerance. The purpose of our study was to investigate the histopathology, FOXP3+CD4+CD25highTreg (FOXP3+ Treg) cell expression, and immune responses in children with H. pylori infection. Twenty-four H. pylori–positive and 24 H. pylori–negative children who underwent esophagogastroduodenoscopy for dyspeptic symptoms were included. Histopathologic grading according to the updated Sydney classification and immunohistochemical stains for FOXP3, transforming growth factor–β1 (TGF-β1), and CD4 were performed. Histopathologic bacterial density score, gastritis activity score, and chronic inflammation score were higher in the H. pylori–positive group than in the negative group (P < 0.01). The number of FOXP3+Treg cells and CD4+T cells and the grade of TGF-β1 expression were significantly increased in the H. pylori–positive group compared to the negative group (P < 0.01). The number of FOXP3+Treg cells correlated positively with the grade of TGF-β1 expression regardless of H. pylori status (P < 0.05). The number of FOXP3+Treg cells and the grade of TGF-β1 expression correlated positively with H. pylori density, gastritis activity score, and chronic inflammation score regardless of H. pylori status (P < 0.01). These findings indicate that FOXP3+Treg cells could play a role in persistent H. pylori infection.