Esophageal IgE, IgG4, and mucosal eosinophilia in individuals with dysphagia

Background Eosinophilic esophagitis (EoE) is an inflammatory disease of the esophagus, producing failure to thrive in infants and dysphagia with food impaction in older children and adults. Although most people with EoE manifest atopic/allergic disease, the specific allergens to which immunoglobulin E (IgE) is directed, if any, have not yet been characterized. Methods Mucosal brush biopsy (MBB) and solid tissue biopsy (STB) specimens were prospectively obtained from 25 individuals with dysphagia and suspicion of EoE. Specific IgE (sIgE) against 112 epitopes from airborne and food proteins, antigens known to cause a polyclonal IgE response and IgG4 to food allergens, were measured. Results There was no difference in total IgE harvested between the 2 biopsy methods (p > 0.05) or between the EoE-positive (N = 12) and EoE-negative (N = 13) groups (p > 0.05). None of the samples in either group contained measurable serum IgE to any of the airborne or food proteins tested, but low levels of IgE specific to Candida and Staphylococcus enterotoxins were detected. Low levels of IgG4 specific to wheat, soy, peanut, and egg were also detected. Conclusions Both MBB and STB are able to harvest measureable levels of IgE and IgG4 from the esophageal mucosa. Low levels of serum-specific IgE suggest that other inflammatory mechanisms, besides type I, IgE-mediated, allergen-specific hypersensitivity, may act as the primary catalyst for mucosal eosinophilia. Clarifying the role of both IgE-mediated and non-IgE-mediated inflammatory mechanisms will help identify more targeted diagnostic and treatment strategies for individuals who present with dysphagia and esophageal eosinophilia.