Atopic and non-atopic eosinophilic oesophagitis are distinguished by immunoglobulin E-bearing intraepithelial mast cells

Aims: Eosinophilic oesophagitis (EoE) occurs in atopic individuals and features eosinophils and mast cells, but differences in the inflammatory cell density between the epithelium and lamina propria (LP) are not fully understood. The aim of this study was to determine if numbers of eosinophils, B lymphocytes and immunoglobulin E (IgE)-bearing mast cells are increased in the mucosa of EoE patients with and without concurrent atopy. Methods and results: Oesophageal biopsies containing >= 4 high-power fields (HPF) of epithelium and LP were identified for normal (n = 9), gastroesophageal reflux disease (GERD) (n = 5) and EoE (n = 25) patients. Patients were classified as atopic or not by clinical history. Immunohistochemistry identified mast cells, B lymphocytes and eosinophils. Eosinophil density was increased in the LP in EoE. Intraepithelial eosinophil density correlated with eosinophils/HPF, CD20(+) B lymphocyte density and tryptase(+) IgE(+) mast cell density. Increased intraepithelial IgE(+) cell density in EoE was associated with mast cells and not B lymphocytes. Intraepithelial IgE(+) mast cell densities were significantly higher in biopsies from the subgroup of EoE patients with atopy. Conclusions: EoE diagnosis using maximal eosinophil count/HPF correlates with average counts/mm(2), and intraepithelial eosinophil densities are higher in children than adults with EoE. In EoE, numbers of eosinophils and mast cells are increased in the LP. IgE-bearing mast cells are increased in atopic EoE patients but not in non-atopic EoE patients.