Indexed on: 03 Sep '16Published on: 03 Sep '16Published in: Allergy
Overlapping seasons and cross reactivity, especially to grass pollen profilin, can hamper the diagnosis of birch pollen allergy. To identify the primary sensitizing allergen and the clinical relevance of cross sensitization, we correlated sensitization profiles with in vitro and in vivo tests, symptom scores and pollen counts.433 patients with positive skin prick test (SPT) to birch pollen were analyzed regarding IgE to major birch and grass pollen allergens Bet v 1 and Phl p 1/p 5 and the profilins Bet v 2 and Phl p 12. Subgroups were analyzed by basophil activation test (BAT) and CAP-FEIA based cross- and self-inhibition tests.349 patients were sensitized to Bet v 1, 44 to both Bet v 1 and Bet v 2 and 15 patients to Bet v 2 only. From Bet v 2 sensitized patients 40 were also sensitized to Phl p 12. Ex vivo, Bet v 2 and Phl p 12 induced dose dependent activation in basophils of these patients. Cross- and self-inhibition tests with both allergens confirmed cross reactivity. However, semi-quantitative analysis of SPTs demonstrated markedly increased reactivity to grass compared to birch pollen extract in Bet v 2 only sensitized patients. Accordingly, in most of those patients clinical symptoms precisely correlated with grass pollen counts.Identification of the clinically relevant and sensitizing allergen needs correlation of actual pollen counts with clinical symptoms and sensitization status to major allergens. Semi-quantitative analysis of SPT or BAT and determining profilin-specific IgE can contribute to making the diagnosis. This article is protected by copyright. All rights reserved.