Foxp3 expression in duodenal mucosa in pediatric patients with celiac disease

Objective: It was the aim of this study to evaluate the number of 2 lymphoid subpopulations, CD8⁺ cells and FOXP3⁺, in the duodenum mucosa from pediatric celiac patients. Methods: Tissue sections prepared from paraffin-embedded biopsies of the descending duodenum of 61 celiac patients with Marsh grade 1 (M1), M2 and M3 disease and biopsies from 21 age-matched non-celiac (NC) patients were immunohistostained with anti-CD8 or FOXP3 antibodies. Results: The histological Marsh grade correlated with the mean number of FOXP3⁺ cells in the lamina propria (LP) mucosa (8.9 ± 1.1, 6.8 ± 2.4, 24.5 ± 2.6 and 31.1 ± 2.8 for NC, M1, M2 and M3 biopsies, respectively; p < 0.001). Using a cutoff point of 15 cells, 95% of NC and 88% of M1 biopsies had a mean of <15 FOXP3⁺ cells compared with 14% for M2 and 13% for M3 biopsies. The number of FOXP3 ⁺ cells in the epithelial mucosa also correlated with transglutaminase type 2 serum levels from the celiac patients. Unlike the FOXP3⁺ cells, CD8⁺ lymphocytes were present in both LP and surface epithelial mucosa and significantly different only in the LP mucosa of the M2 and M3 groups. Conclusion: The number of FOXP3⁺ cells is substantially increased in the mucosa of celiac patients at advanced stages. Characterization of the activity of these cells in celiac and in other inflammatory bowel diseases will enable us to understand the significance of these cells in celiac disease.