Mucosal Immunity Related to FOXP3+ Regulatory T Cells, Th17 Cells and Cytokines in Pediatric Inflammatory Bowel Disease

Background: We aimed to investigate mucosal immunity related to forkhead box P3 (FOXP3(+)) regulatory T (Treg) cells, T helper 17 (Th17) cells and cytokines in pediatric inflammatory bowel disease (IBD). Methods: Mucosal tissues from terminal ileum and colon and serum samples were collected from twelve children with IBD and seven control children. Immunohistochemical staining was done using anti-human FOXP3 and anti-ROR gamma t antibodies. Serum levels of cytokines were analyzed using a multiplex assay covering interleukin (IL)-1 beta, IL-4, IL-6, IL 10, IL-17A/F, IL-21, IL-22, IL-23, IL-25, IL-31, IL-33, interferon (IFN)-gamma, soluble CD40L, and tumor necrosis factor-alpha. Results: FOXP3(+) Treg cells in the lamina propria (LP) of terminal ileum of patients with Crohn's disease were significantly (P < 0.05) higher than those in the healthy controls. ROR gamma t(+) T cells of terminal ileum tended to be higher in Crohn's disease than those in the control. In the multiplex assay, serum concentrations (pg/mL) of IL-4 (9.6 +/- 1.5 vs. 12.7 +/- 3.0), IL-21 (14.9 +/- 1.5 vs. 26.4 +/- 9.1), IL-33 (14.3 +/- 0.9 vs. 19.1 +/- 5.3), and IFN-gamma (15.2 +/- 5.9 vs. 50.2 +/- 42.4) were significantly lower in Crohn's disease than those in the control group. However, serum concentration of IL-6 (119.1 +/- 79.6 vs. 52.9 +/- 39.1) was higher in Crohn's disease than that in the control. Serum concentrations of IL-17A (64.2 +/- 17.2 vs. 28.3 +/- 10.0) and IL-22 (37.5 +/- 8.8 vs. 27.2 +/- 3.7) were significantly higher in ulcerative colitis than those in Crohn's disease. Conclusion: Mucosal immunity analysis showed increased FOXP3(+) T reg cells in the LP with Crohn's disease while Th17 cell polarizing and signature cytokines were decreased in the serum samples of Crohn's disease but increased in ulcerative colitis.