SCOPE: The aim was to investigate the potential contribution of a major birch pollen Bet v 1-homologous allergen to birch pollen-associated tomato fruit allergy. METHODS AND RESULTS: Two isoforms of a Bet v 1-homologous protein (designated Sola l 4) from tomato fruit were identified by cDNA-cloning and produced as recombinant proteins. Allergen-specific IgE levels to tomato, birch pollen, Bet v 1, and Sola l 4 were determined in birch pollen allergic patients with allergy or tolerance to tomato. Sola l 4 was recognized in 76% of birch/tomato allergic patients, while tomato- and Bet v 1-specific IgE was detectable in 64% and 81% of sera. Almost all patients sensitized to Bet v 1 reacted with Sola l 4. Both Sola l 4 isoforms displayed allergenic potency and IgE-cross-reactivity with Bet v 1 as investigated by competitive ELISA and in vitro mediator release assay. Nevertheless, the reactivity pattern of patients' sera was diverse. CONCLUSION: Sola l 4, a novel pathogenesis related-10 protein, qualifies as major allergen in tomato fruits. Data suggest Sola l 4 as class II allergen. IgE-testing using Sola l 4 showed low clinical specificity, but high sensitivity in tomato allergic patients and will further improve component-resolved allergy diagnosis.
SCOPE: The aim was to investigate the potential contribution of a major birch pollen Bet v 1-homologous allergen to birch pollen-associated tomato fruit allergy. METHODS AND RESULTS: Two isoforms of a Bet v 1-homologous protein (designated Sola l 4) from tomato fruit were identified by cDNA-cloning and produced as recombinant proteins. Allergen-specific IgE levels to tomato, birch pollen, Bet v 1, and Sola l 4 were determined in birch pollen allergicpatients with allergy or tolerance to tomato. Sola l 4 was recognized in 76% of birch/tomato allergicpatients, while tomato- and Bet v 1-specific IgE was detectable in 64% and 81% of sera. Almost all patients sensitized to Bet v 1 reacted with Sola l 4. Both Sola l 4 isoforms displayed allergenic potency and IgE-cross-reactivity with Bet v 1 as investigated by competitive ELISA and in vitro mediator release assay. Nevertheless, the reactivity pattern of patients' sera was diverse. CONCLUSION: Sola l 4, a novel pathogenesis related-10 protein, qualifies as major allergen in tomato fruits. Data suggest Sola l 4 as class II allergen. IgE-testing using Sola l 4 showed low clinical specificity, but high sensitivity in tomato allergicpatients and will further improve component-resolved allergy diagnosis.