PURPOSE: The study aimed to investigate the recruiting of T lymphocytes including IL-7Ralpha(low) CX3CR1(+) effector memory (EM) CD8(+) T cells and alpha4beta7 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-7Ralpha(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 alpha4beta7(+) 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-alpha 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 alpha4beta7(+) 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-7Ralpha(low)CX3CR1(+) and integrin alpha4beta7(+) CD4(+) T cells might be highly associated with the pathogenesis of ulcerative colitis.