Expression of IL-7Rα(low)CX3CR1(+) CD8(+) T Cells and α4β7 Integrin Tagged T Cells Related to Mucosal Immunity in Children with Inflammatory Bowel Disease.

PURPOSE: The study aimed to investigate the recruiting of T lymphocytes including IL-7Rα(low) CX3CR1(+) effector memory (EM) CD8(+) T cells and α4β7 integrin tagged T cells to inflamed intestinal mucosa. METHODS: Whole blood and mucosal tissues of intestine were collected from 40 children with or without inflammatory bowel disease (IBD). T cell surface staining and immunohistochemistry were done with several antibodies in peripheral blood mononuclear cells (PBMCs) and intestinal mucosa, respectively. Serum levels of cytokines were measured by ELISA. RESULTS: The frequency of IL-7Rα(low)CX3CR1(+) EM CD8(+) T cells in the PBMC was significantly higher in the ulcerative colitis group than in the control group (57.9±17.80% vs. 33.9±15.70%, p=0.021). The frequency of integrin α4β7(+) CD4(+) T cells in the PBMC was significantly lower in the ulcerative colitis group than in the control group (53.2±27.6% vs. 63.9±13.2%, p=0.022). Serum concentration of TNF-α was higher in the Crohn's disease group than in the control group (26.13±5.01 pg/mL vs. 19.65±6.07 pg/mL, p=0.008). Of the three groups, the ulcerative colitis group had the highest frequency of integrin α4β7(+) T cells based on immunohistochemistry analyses for intestinal tissues, followed by the Crohn's disease group and the control group (4.63±1.29 cells vs. 2.0±0.57 cells vs. 0.84±0.52 cells, p<0.001). CONCLUSION: Trafficking immune cells with effector memory CD8(+) T cells clarified by IL-7Rα(low)CX3CR1(+) and integrin α4β7(+) CD4(+) T cells might be highly associated with the pathogenesis of ulcerative colitis.