Tomato (Lycopersicon esculentum) allergens in pollen-allergic patients

This study was undertaken to investigate the relevance of tomato allergy in pollen-allergic patients, and to identify and characterize tomato allergens. Therefore, sera of a group of 32 pollen-allergic patients with a history of adverse reactions to tomato were investigated by means of immunoblotting and specific IgE measurements (CAP, EAST, EAST inhibition and CCD [crossreactive carbohydrate determinants]-ELISA). IgE-reactive spots on 2D blots were analyzed by amino acid microsequencing. Tomato allergy was found to occur with a prevalence of about 9% in our group of birch pollen-allergic patients. Of the patients with adverse reactions to tomato, 44% presented I-E to tomato profilin and 35.5% specific IgE to CCD. Two patients were sensitized to a lipid transfer protein in tomato. Microsequencing of other IgE-reactive proteins, separated by 2D-gel electrophoresis and transferred to PVDF membranes, revealed beta -fructofuranosidase, polygalacturonase 2A, and pectinesterase as further tomato allergens. Our data show that tomato is a relevant allergenic food in pollen-allergic patients. It seems that the majority of pollen-associated allergies to tomato is caused by known ubiquitous allergenic structures such as profilin and cross-reactive IgE-binding N-glycans. Furthermore, lipid transfer protein, as well as polygalacturonase 2A, pectinesterase and beta -fructofuranosidase may represent birch pollen-independent tomato allergens for certain patients.