Diagnostic value of birch recombinant allergens (rBet v 1, profilin rBet v 2) in children with pollen-related food allergy.

Objective: Pollen-related food allergy to fresh fruits and vegetables is a well-known clinical phenomenon. Bet v 1, the major birch pollen allergen, has been cloned and shows homologies to various food allergens (e.g. hazelnut, apple, celery, tomato). Allergy to profilin Bet v 2 was also described in 10-15% of patients sensitized to birch pollen. Objective of our work was to assess the diagnostic value of recombinant allergens (rBet v 1, rBet v 2) for diagnosis of children sensitized to birch pollen with associated food allergy.

Methods: The investigations were carried out on the group of 14 children aged 4-17 years, with a history of allergic reactions and sensitized to birch pollen with associated food allergy. Skin prick tests were performed with natural foods and commercial aeroallergens (Bencard). Sera-specific IgE antibodies to recombinant and other allergens (Pharmacia Upjohn) were measured with a fluoroimmunoenzymatic essay (UniCAP). Oral food challenge tests were performed to confirm adverse food reactions.

Results: 64% were sensitized to rBet v 1, 14% to rBet v 2, 7% to both of them. 50% of children with allergy to Bet v 1 had also concomitant allergy to other pollens and food allergy to fruits from family Rosaceae. Patients with positive reaction to Bet v 2 represented allergy to vegetables from family Umbelliferae. The most common form of allergic reactions were: allergic rhinitis in 64%, atopic dermatitis in 36%, oral allergy syndrome in 21% of investigated children.

Conclusions: Use of two recombinant allergens permits the diagnosis of birch pollen sensitization in children with food-pollen related allergy and gives the pattern of possible cross-reactivity between pollen and food allergens in children with allergic diseases.