Clinical characterization and IgE profiling of birch (Betula verrucosa)--allergic individuals suffering from allergic reactions to raw fruits and vegetables

Background: Hypersensitivity to raw fruits and vegetables is often associated with respiratory allergy to birch (Betula verrucosa) pollen and is considered to be the most prevalent form of food allergy in adults sensitized to birch pollen.

Objective: The aim of the study was to investigate the association of clinical allergy and IgE profiles in individuals with birch pollen allergy and hypersensitivity to raw fruits and vegetables.

Methods: A total of 59 adults with clinical and skin prick test confirmed birch pollen allergy were included in the study. All the subjects were interviewed by using a structured questionnaire and were examined in vivo by the open test, with the appropriate fruits and vegetables. ImmunoCAP and ImmunoCAP ISAC were used as in vitro diagnostics to assess sensitization profiles for each individual, and principal components analysis was used to analyze the IgE data sets.

Results: Of 59 individuals, 54 (92%) had positive prick-prick test with raw potato, carrot, apple, and/or hazelnut, and the skin prick test was always positive when the corresponding skin challenge was defined as positive. Specific IgE in the ImmunoCAP and inhibition assays with rMal d 1 and rBet v 1 demonstrated that Bet v 1 is driving the sensitization against pathogenesis related-10 proteins. However, positive IgE in vitro results could not be used to predict clinical reactivity to raw fruits and vegetables.

Conclusions: The present study showed that component-based IgE profiling does not enhance the diagnostic potential in case of pollen-food syndrome, which may be associated with other as yet unidentified components.