Cor a 1areactive T cells and IgE are predominantly cross-reactive to Bet v 1 in patients with birch pollenaassociated food allergy to hazelnut

• Published in: Journal of allergy and clinical immunology Vol. 131; no. 5; pp. 1384 - 1392.e6
• Main Authors: Hofmann, Claudia, Scheurer, Stephan, Rost, Kathrin, Graulich, Edith, Jamin, Annette, Foetisch, Kay, Saloga, Joachim, Vieths, Stefan, Steinbrink, Kerstin, Adler, Henric S
• Format: Journal Article
• Language: English
• Published: 01.05.2013
• Subjects: Corylus; Daucus
• ISSN: 0091-6749

Background: IgE- and T-cell cross-reactivity contribute to the birch pollenafood syndrome. Objectives: We performed a comprehensive analysis of T-cell cross-reactivity in primary cell cultures, facilitating the identification of allergen-specific T-cell subpopulations from individual patients. Methods: Patients with birch pollen allergy and associated food allergy to hazelnuts, carrots, or both were analyzed for IgE cross-reactivity, T-cell responses, and T-cell cross-reactivity to recombinant Bet v 1.0101 (Bet v 1; birch), Cor a 1.0401 (Cor a 1; hazelnut), and Dau c 1.0104 (Dau c 1; carrot). AANBnovel flow cytometryabased method using a 2-step staining process with fluorescent dyes was established to identify subpopulations of cross-reactive T cells. Results: IgE-binding inhibition tests of individual sera revealed that the vast majority of Cor a 1areactive IgE was cross-reactive to Bet v 1, whereas Bet v 1areactive IgE was only partially inhibited by preincubation with Cor a 1. Primary stimulation of T cells with Bet v 1 or Cor a 1 resulted in a significant increase in specific responses to Cor a 1 or Bet v 1 after secondary stimulation, respectively, indicating T-cell cross-reactivity between birch and hazelnut allergens in all patients of the study cohort. Preactivation with Dau c 1 induced less pronounced effects. AANBnovel flow cytometryabased proliferation assay identified a predominant Cor a 1/Bet v 1across-reactive T-cell subpopulation within highly Bet v 1/Cor a 1aresponsive T cells. Conclusions: Analysis of primary allergen-specific T cells combined with flow cytometryabased proliferation assays facilitates investigation of allergen-specific T-cell subpopulations in subjects and might be helpful to evaluate the effect of birch-specific immunotherapy on pollen-associated food allergies.