Mucosal Immunity Related to CD8+ T Lymphocytes in Children with Helicobacter pylori Gastritis

Purpose We investigated the role of CD8(+)T cells as host immune factors in pediatric patients with Helicobacter pylori gastritis. Methods Gastric mucosal tissue and blood samples were collected from 39 children, including 11 children with H. pylori infection and 28 children as controls. Anti-CD8 and anti-T-bet antibodies were used for immunohistochemistry of the gastric mucosa. For the cell surface and intracellular staining, peripheral blood mononuclear cells were stained with anti-IL7R alpha, anti-CX3CR1, anti-CD8, anti-T-bet, and anti-IFN-gamma antibodies. Cytokines of sera such as tumor necrosis factor alpha (TNF-alpha) and CX3CL1 were analyzed using enzyme- linked immunosorbent assay (ELISA). Results In the immunohistochemistry of gastric mucosa, the frequency of CD8(+) and T-bet(+) T cells cells was higher in the H. pylori-positive group than in the control group (26.9 +/- 7.8% vs. 16.9 +/- 3.3%, p<0.001; 5.0 +/- 2.5% vs. 2.2 +/- 0.7%, p=0.001). Between the control and H. pylori-positive groups, the frequency of IL-7R alpha(low)CX3CR1(+) CD8(+) and T-bet(+) INF-gamma(+) CD8(+) T cells were not significantly different between surface and intracellular staining, respectively (40.4 +/- 24.0% vs. 38.2 +/- 17.8%, p=0.914; 40.4 +/- 24.0% vs. 38.2 +/- 17.8%, p=0.914). In the ELISA, no significant differences in TNF-alpha and CX3CL1 concentrations were observed between the control and H. pylori-positive groups (34.3 +/- 12.1 pg/mL vs. 47.0 +/- 22.6 pg/mL, p=0.114/0.5 +/- 0.1 pg/mL vs. 0.5 +/- 0.1 pg/mL, p=0.188). Conclusion CD8(+) T and Th1 cells, which secrete IFN-gamma, might play important roles in the mucosal immunity of the stomach in children with H. pylori infection.