Expression of IL-7RαlowCX3CR1+ CD8+ T Cells and α4β7 Integrin Tagged T Cells Related to Mucosal Immunity in Children with Inflammatory Bowel Disease.

Abstract

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^lowCX3CR1⁺ 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^lowCX3CR1⁺ and integrin α4β7⁺ CD4⁺ T cells might be highly associated with the pathogenesis of ulcerative colitis.