The incidence of eosinophilic esophagitis (EoE), a Th2-type allergic disease of the esophagus, has increased with the higher prevalence of gastroesophageal reflux disease (GERD). Both conditions are chronic inflammatory diseases with similar clinical presentations, yet their pathogenesis is thought to differ. Recent evidence indicates that forkhead box P3 (FOXP3)-positive regulatory T cells (Tregs) play a critical role in immune tolerance and control of Th2-biased responses in various allergic diseases.
This study aimed to investigate differences in Treg induction between EoE and GERD and clarify whether this difference was related to the clinicopathological findings of patients with EoE.
Thirty patients (15 men, 15 women) with EoE and 30 patients (15 men, 15 women) with GERD were included. Patient characteristics, including endoscopic and pathological findings, were compared between the two groups. Immunohistochemistry staining was used to identify T lymphocytes and Tregs. Tregs were identified by CD3 + FOXP3 + staining, and T cells were defined as CD3 + cells. The number of T cells and Tregs in the epithelium was counted, and the average of Tregs/T cells was calculated.
The ratio of Tregs/CD3 + T cells in the esophageal epithelium was significantly lower in the EoE group than in the GERD group (9.9% vs. 23.6%, P = 0.0000012). Comparison of the ratio of Tregs/CD3 + T cells by age, gender, endoscopic findings, and histological findings in patients with EoE revealed a significant difference in gender.
Treg induction was impaired, and this effect was more pronounced in male adult patients with EoE than those with GERD.

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