Comparative Analysis of FcεRI Expression Patterns in Patients With Eosinophilic and Reflux Esophagitis

Background and Objective: Eosinophilic esophagitis (EoE) is an allergic disease of the esophagus. The IgE receptors on immune cells that infiltrate the esophagus are poorly defined. The high-affinity receptor for IgE, Fc epsilon RI, may play a role in EoE. The objective of the present study is to identify and compare the IgE receptors in the esophageal epithelium of patients with EoE, reflux esophagitis (RE), and normal controls. Patients and Methods: A retrospective case-control study of 62 patients (19 EoE, 22 RE, 21 normal controls) was conducted. Biopsies were immunostained for Fc epsilon RI, CD23, galectin-3, c-kit, CD1a, and langerin. Results: Fc epsilon RI was the only IgE receptor present in the esophageal epithelium of patients with EoE. The Fc epsilon RI-positive cell count varied by diagnosis (proximal biopsies EoE 32.6 +/- 19.0 cells/high-power field, RE 26.7 +/- 16.6, controls 15.6 +/- 8.3, ANOVA P = 0.005; distal biopsies EoE 24.2 +/- 16.2, RE 35.7 +/- 27.6, controls 15.3 +/- 8.4, P = 0.006). In the proximal esophagus, the Fc epsilon RI count was higher in EoE than in controls (P = 0.006); in the distal esophagus, the Fc epsilon RI count was higher in RE than in controls (P = 0.004). EoE and RE had similar Fc epsilon RI-positive cell counts. A subset of Fc epsilon RI-positive cells was similar in morphology and distribution to Langerhans cells (CD1a and langerin positive). Conclusions: The presence of Fc epsilon RI-positive cells in high numbers in the esophageal epithelium implies this receptor must be critical in the IgE-mediated activation of immune cells in the esophagus. Langerhans cells in the esophageal epithelium appear to express Fc epsilon RI. The role of Langerhans cells in the pathophysiology of EoE needs to be elucidated.