Background: Oral allergy syndrome (OAS) is a common condition among patients allergic to tree pollen. The similarities in antigen structure of pollen and of fruit and vegetable allergen epitopes are considered to be among the most likely underlying causes resulting in the production of cross-reacting IgE antibodies.Material/Methods: This study was carried out in 86 adults allergic to tree pollen, some of whom were diagnosed with OAS. All participants were screened for sIgE for mixed allergens of Betulaceae trees, Bet v 1, Bet v 2, and apple allergens by means of the immunoenzymatic ELISA assay. The results were compared for patients with and without concomitant OAS. Results: The presence of anti-Bet v 1 sIgE was found in 93% of the participants, with statistically significant higher levels in the OAS group compared to the non-OAS group. Similarly in the OAS group anti Bet v 2 antibodies were found far more frequently and, as a rule, were accompanied by antibodies against apple allergens. Conclusions: Clear differences were identified in the OAS group in terms of the levels and incidence of sIgE antibodies against particular allergen epitopes of tree pollen.

Keywords: oral allergy syndrome, Bet v 1, Bet v 2, sIgE concentration