IgE, IgG4 and IgA specific for Bet v 1-related food allergens do not predict oral allergy syndrome.

Birch pollen-associated plant food allergy is caused by Bet v 1-specific IgE, but presence of cross-reactive IgE to related allergens does not predict food allergy. The role of other immunoglobulin isotypes in the birch pollen-plant food syndrome has not been investigated in detail.

Bet v 1-sensitised birch pollen-allergic patients (n = 35) were diagnosed for food allergy by standardised interviews, skin prick tests, prick-to-prick tests and ImmunoCAP. Concentrations of allergen-specific IgE, IgG1, IgG4 and IgA to seven Bet v 1-related food allergens were determined by ELISA.

Bet v 1, Cor a 1, Mal d 1 and Pru p 1 bound IgE from all and IgG4 and IgA from the majority of sera. Immunoglobulins to Gly m 4, Vig r 1 and Api g 1.01 were detected in less than 65% of the sera. No significant correlation was observed between plant food allergy and increased or reduced levels of IgE, IgG1, IgG4 or IgA specific for most Bet v 1-related allergens. Api g 1-specific IgE was significantly (p = 0.01) elevated in celeriac-allergic compared to celeriac-tolerant patients. Likewise, frequencies of IgE (71% versus 15%; p = 0.01) and IgA (86% versus 38%; p = 0.04) binding to Api g 1.01 were increased.

Measurements of allergen-specific immunoglobulins are not suitable for diagnosing Bet v 1-mediated plant food allergy to hazelnut and Rosaceae fruits. In contrast, IgE and IgA to the distantly related allergen Api g 1 correlate with allergy to celeriac. This article is protected by copyright. All rights reserved.