• EPITHELIAL BARRIER
• IMMUNE RESPONSE
• OESOPHAGITIS

Eosinophilic oesophagitis (EoE) is a chronic inflammatory condition of the oesophagus, with a rapidly increasing prevalence and incidence.1 When EoE first appeared on the medical landscape—introduced by two independent, but coincident case series almost three decades ago—it was considered a rare disease.2 3 Today, EoE represents the most frequent cause of solid food dysphagia, with incidence and prevalence rates comparable with those of Crohn’s disease, at least in the Western hemisphere.4

Immunological studies revealed a T helper 2 (Th2)-type inflammatory (allergic) response in EoE.5 High efficiency of allergen-free diets, amino acid-based formula in particular,6 further supported the concept of EoE being a food allergy. Of note, EoE is a late-phase allergic reaction, mainly involving T cells,7 rather than an IgE-mediated response, as IgE plays at best a subsidiary role in its pathogenesis. IgE-based allergic tests have therefore shown disappointing correlation with trigger food identification. How allergens in EoE result in the aforementioned Th2-type inflammatory response still is only partially known.

The hypothesis of epithelial barrier dysfunction has recently gained attraction. In order to evoke …