LAUSR

Objective: Eosinophilic esophagitis (EoE) is considered a TH2-mediated food allergy disease that leads to submucosal esophageal fibrosis and strictures. Recent studies focused on adults with EoE identified a strong association with elevated esophageal IgG4 immunostaining. Our study aimed to determine the association of IgG4 with EoE in pediatric patients. Methods: Using our local EoE research registry, we identified 41 adequate biopsies from EoE patients. We used 10 age- and sex-matched patients with no diagnostic abnormalities at endoscopy or on biopsy. Using a monoclonal antibody to Immunoglobulin G4 (IgG4), we determined the maximum density of IgG4-positive plasma cells (IgG4-PC) per high-power field (hpf). Using a semi-quantitative assessment, we also graded the noncellular staining of the lamina propria and epithelium. Results: Our EoE cohort consisted predominantly of boys with an average age of 5.9 years and 63% had a documented IgE-based food allergy. Median peak eosinophilia was 40 eosinophils/hpf and the median IgG4-PC density was 39/hpf in the active esophagitis patients, compared with a median of 0 IgG4-PC/hpf in the non-EoE patients (P = 0.0001). EoE patients with a food allergy showed a significantly higher IgG4-PC density (44.5/hpf) than those without a food allergy (8/hpf; P = 0.0385). There was no significant association between IgG4-PC density and peak eosinophilia (r2 = 0.0011). Conclusions: We demonstrate that active esophagitis in pediatric EoE patients is associated with elevated levels of IgG4-positive plasma cells, which was more significant in EoE patients with a documented food allergy. Our study also adds to the growing literature that EoE may involve more than just an exaggerated TH2 immune response.