Allergy to apple cultivars among patients with birch pollinosis and oral allergy syndrome.

BACKGROUND: Oral allergy syndrome (OAS) is caused by cross-reacting allergens found in pollen, raw fruits, vegetables, and some tree nuts. The major apple allergen, Mal d 1, is a cause of food allergic reactions in birch pollen sensitized patients. OBJECTIVE: To explore the allergenicity of the most popular and commonly consumed apple cultivars in Poland in patients with birch pollen allergy with or without OAS. METHODS: Data were obtained from 46 adults with clinical symptoms of birch allergy and allergic rhinitis or rhinoconjunctivitis. Patients were divided into 2 groups according to the occurrence of OAS to apple. Skin prick tests (SPTs) were performed with pulp from the 11 most popular apple cultivars in Poland. Specific IgE (sIgE) to Bet v 1 was measured by radioallergosorbent test. RESULTS: Patients with OAS had more positive responses to apple SPT vs patients without OAS (odds ratios, 4.8-11.96). Patients with OAS had distinctive responses to apple cultivars. Szara Reneta and Cortland induced positive responses in 50% and 83% of patients, respectively. Patients with OAS vs patients without OAS who were allergic to apples vs nonallergic had 2-fold (P = .008) and 7-fold (P = .03) higher blood concentrations of sIgE Bet v 1, respectively. There were different profiles of correlations of sIgE Bet v 1 with wheal diameter for low and high allergenic cultivars in patients without and with OAS. CONCLUSION: We noted a substantial role for Bet v 1 sensitization in the allergic response based on evaluation of the allergenicity of 11 apple cultivars. The sIgE Bet v 1 and SPT results of patients with and without OAS allowed differentiation between low and high allergenic cultivars.