Germination of pollen grains in the esophagus of individuals with eosinophilic esophagitis (EoE)

After clinical and anatomo-pathological diagnosis of the patients, comorbidity between eosinophilic esophagitis (EoE) and pollen hypersensitivity was evident. Pollen allergens were detected in 87.6% of patients with EoE. The predominant allergens were grasses group 1 (55%), followed by Art v 3 (11.3%) and other lipid transfer proteins of peach and mugwort, hazelnuts and walnuts. Callose was found in 65.6% of the biopsies of patients positive for pollen allergens and not in the controls. We observed pollen tubes surrounded by eosinophils in the proximal and middle esophageal mucosa, resulting in microabcesses. Eosinophils act as if they are responding to parasitic infections, drug reactions, or neoplasms. In patients with eosinophilic esophagitis (EoE) we have been able to demonstrate a high incidence of sensitization to pollen found in the nasopharyngeal mucosa and that could be swallowed. Alteration of the mucosal barrier due to desmoglein or a weakness of the innate immune response could be the cause of the penetration of pollen grains into the tissues of the esophagus. Subsequent germination of pollen and release of highly allergenic molecules resistant to digestion such as LTPs and expansins of group 1 of grasses could be responsible for the increase of the symptoms in these patients during the periods of greater pollination.