FOXP3+T Cells and TGF-β1 in Colonic Mucosa of Children with Crohn's Disease

Purpose: Forkhead box protein 3 (FOXP3)+T cells are the major regulatory T cells controlling all aspects of the immune response. Transforming growth factor-β (TGF-β) is a suppressive cytokine which mediates the suppressive action of FOXP3+T cells. The aim of this study was to investigate the role of FOXP3+T cells, TGF-β in colonic mucosa of children with Crohn’s disease (CD). Methods: Colonic mucosal biopsies were obtained from 10 children with CD (12∼15 years of age) and 11 control (8∼15 years of age). Frequencies of FOXP3+T, CD4+T cells and TGF-β1 expression were examined in the lamina propria (LP) and lymphoid aggregates or follicles (LA/F) by immunohistochemistry, and later evaluated by association with disease activity. Results: In the LP of CD group, frequencies of FOXP3+T, CD4+T cells, proportion of FOXP3/CD4+T cells and TGF-β1 expression significantly increased compared to the control. In the LA/F of CD group, frequency of FOXP3+T cells, proportion of FOXP3/CD4+T cells and TGF-β1 expression significantly increased compared to the control (p＜0.05). CD4+T cells also increased compared to the control, but this finding was not significant. In the LP and LA/F of CD group, frequency of FOXP3+T cells exhibited positive correlation with CD4+T cells (p＜0.05). In the LP and LA/F of CD group, TGF-β1 expression had positive correlation with CRP, Pediatric Crohn's Disease Activity Index, and negative correlation with hematocrit and albumin (p＜0.05). Conclusion: Increased frequency of FOXP3+T cells and TGF-β1 expression in colonic mucosa of CD can be interpreted as a compensatory increase towards achieving down-regulation of immune responses. (Korean J Pediatr Gastroenterol Nutr 2011; 14: 258∼268)