<p>Enhancement of Circulating and Intestinal T Regulatory Cells and Their Expression of Helios and Neuropilin-1 in Children with Inflammatory Bowel Disease</p>

Abstract

Background/Aims: The proportions of intestinal and peripheral regulatory T cells (Tregs) in pediatric inflammatory bowel disease (IBD) were poorly investigated, as well as different subsets of these cells. Helios and Neuropilin-1 were proposed as markers differentiating between thymic and peripheral Tregs. Therefore, the aim of current work was to investigate the proportions of Tregs and expression of Helios and Neuropilin-1 in Tregs in peripheral blood and intestinal mucosa of children with inflammatory bowel disease. Materials and methods: Fifteen patients newly diagnosed with inflammatory bowel disease: ulcerative colitis (n=7) and Crohn’s disease (n=8) were included in the study. Nine children who presented with no abnormalities in colonoscopy served as a control group. Quantification of regulatory T cells of the CD4 + CD25 high FOXP3 + phenotype, as well as Helios + and Neuropilin-1 + in peripheral blood and bowel mucosa was based on multicolor flow cytometry. Results: The rates of circulating and intestinal Tregs were significantly higher in the studied group than in the control group. The rate of intestinal T regulatory lymphocytes was significantly higher than circulating Tregs in patients with IBD, but not in the control group. The median proportion of circulating FOXP3 + Helios + cells amounted to 24.83% in IBD patients and 15.93% in the controls. The median proportion of circulating FOXP3 + Nrp-1 + cells was 34.23% in IBD and 21.01% in the control group. No statistically significant differences were noted for the circulating FOXP3 + Helios + cells and FOXP3 + Nrp-1 + cells between the studied and the control group. Conclusion: The rates of circulating and intestinal T regulatory cells are increased in naïve pediatric patients with IBD. The rate of Tregs is higher in intestinal mucosa than in peripheral blood in patients with IBD. Flow cytometry is a valuable method assessing the composition of infiltrates in inflamed tissue. Helios and Neuropilin-1 likely cannot serve as markers to differentiate between natural and adaptive Tregs. Keywords: T regulatory cells, circulating Tregs, intestinal Tregs, Helios, Neuropilin-1, IBD, inflammatory bowel disease, children