Germination of pollen grains in the oesophagus of individuals with eosinophilic oesophagitis

Background: Eosinophilic oesophagitis (EoE) is characterized by oesophageal dysfunction and, histologically, by eosinophilic inflammation. There is no a clear aetiologic treatment. EoE exacerbations are often seasonal. We hypothesized that the inflammatory response of the oesophageal mucosa in patients with high levels of antibodies to pollen allergens and worsened seasonal EoE might be due to swallowing airborne pollen and the intrusion into the oesophageal mucosa of pollen allergens and pollen tubes, which encounter a pH and humidity resembling the stigma at pollination. Objective: The aim of our study was to demonstrate the possible pathogenic role of environmental allergens in EoE through molecular and anatomopathological studies Methods: One hundred and twenty-nine patients with EoE were tested for environmental and food allergens. Component resolved diagnosis (CRD), histological and botanical analysis was performed. Microscopic examination of oesophageal biopsies of 129 adults patients with EoE, 82 of them with seasonal exacerbation, and 100 controls, with gastroesophageal reflux without eosinophilic infiltrate, were made to verify the presence of callose (polysaccharide abundant in pollen tubes but absent in animal tissues) in the oesophagus. Results: Component resolved diagnosis detected pollen allergens in 87.6% of patients with EoE. The predominant allergens were group 1 grass (55%), Art v 3 (11.3%) and lipid transfer proteins (LTPs) (19.4%) of common Mediterranean foods such as peach, hazelnuts, walnuts and wheat. Callose from pollen tubes was found in 65.6% of biopsies. Conclusion: Alteration of the mucosal barrier in EoE might cause the penetration of pollen grains into the oesophageal tissues. In EoE patients, anatomopathological studies searching for intrusion to plant foods and pollen, and specific-guided diet and immunotherapy after plant structures detection in biopsies, might be effective.