Increased Number of Regulatory T Cells in Children With Eosinophilic Esophagitis

Objectives: There are limited data on the role of regulatory T cells (Treg) in the disease pathology of eosinophilic esophagitis (EoE). We tested the differences in Treg in subjects with EoE compared with those with gastroesophageal reflux disease (GERD) and healthy controls (HC). Patients and Methods: Pediatric patients evaluated by endoscopy were recruited for our study. Participants were categorized into 3 groups: EoE, GERD, and HC. RNA purified from esophageal biopsies were used for real-time quantitative polymerase chain reaction assays and tested for forkhead box P3 (FoxP3) mRNA expression. Treg were identified as CD4+CD25hi CD1271o cells in peripheral blood and as CD3+ / FoxP3+cells in esophageal tissue. Results: Forty-eight subjects were analyzed by real-time quantitative polymerase chain reaction: EoE (n = 33), GERD (n = 7), and HC (n = 8). FoxP3 expression was higher by up to 1.5-fold in the EoE group compared with the GERD and HC groups (P 0.05). The amount of Treg in esophageal tissue was significantly greater in the EoE group (mean 10.7 CD3+/FoxP3+cells/high power field [HPF]) compared with the other groups (GERD, mean 1.7 CD3+/FoxP3+cells/HPF and HC, mean 1.6 CD3+/FoxP3+cells/HPF) (P < 0.05). Conclusions: We show that Treg are increased in esophageal tissue of EoE subjects compared with GERD and HC subjects. The present study illustrates another possible mechanism involved in EoE that implicates impairment of immune homeostasis.