Eosinophil infiltration of the oesophageal mucosa in patients with pollen allergy during the season

Background The oesophagus is normally devoid of eosinophils. There are some disorders accompanying with eosinophil infiltration. Food allergy has been reported as a common reason, especially in children but some other studies have also indicated that aeroallergens might have a role in oesophageal eosinophil accumulation. Objective In this study we investigated whether there is any eosinophil recruitment in the oesophagus of pollen-allergic patients who had respiratory symptoms during the season. Methods Thirty-eight symptomatic patients (allergic rhinitis (AR) with or without asthma) who had sensitization to grass pollen were included in the study during the pollen season. Controls were composed of 25 healthy non-atopics and 24 patients diagnosed as having gastro-oesophageal reflux disease. Reflux was excluded in allergic and non-atopic groups, whereas the presence of allergy was eliminated in control groups. Gastrointestinal endoscopy was performed in all participants, and biopsy specimens were taken from both the proximal and the distal oesophagus to evaluate eosinophil accumulation. At the same time, blood eosinophil numbers were counted. Results Oesophageal eosinophil accumulation was found in 10 allergic patients (26%) and in five patients (21%) with gastro-oesophageal reflux disease but none of the healthy controls had eosinophils (0%) (P < 0.05). Blood eosinophils were higher in these 10 patients than the rest of the 28 patients without infiltration. In this group, blood eosinophils were also correlated with the number of accumulated eosinophils in the oesophagus (P < 0.001). There was more intense eosinophil infiltration at the distal part of the oesophagus in the reflux group when compared with the allergic group (mean 7.6 +/- 5.6 vs. 3.2 +/- 3.7). Nevertheless, eosinophils were found to be concentrated (mean 5.5 +/- 7.3) in the proximal oesophagus of allergic patients, although it was 1.7 +/- 1.5 in reflux patients (P > 0.05). Conclusion Our results showed that eosinophil infiltration might be observed in oesophageal tissue of patients with respiratory tract allergy during the symptomatic period. This finding may possibly reflect the systemic and common mucosal aspects of allergic inflammation.