Antibody profiles and self-reported symptoms to pollen-related food allergens in grass pollen-allergic patients from northern Europe

Background: Most studies on pollen-related food allergy have so far focused on the association of birch/weed pollen allergens and plant food allergy. The aim of this study was to elucidate the allergen spectrum among a group of grass pollen-allergic patients from northern Europe and to relate the results to clinical histories of pollen-related food allergy. Methods: Fifty-eight grass pollen-allergic patients answered a questionnaire regarding allergy to foods. Blood samples were taken to test IgE-reactivity to a large panel of pollen allergens and pollen- and nonpollen-related food allergens using crude allergen extracts and recombinant and native allergens. Results: Three different groups of grass pollen-allergic patients were identified according to their IgE antibody profile: a grass pollen group only (19%), a grass and tree pollen group (29%) and a grass, tree and compositae (pan-) pollen group (48%). No sensitization to Bet v 1 as well as almost no IgE to plant food was observed in the grass pollen group. In contrast, nearly all patients in the two tree-related groups had IgE to Bet v 1, which reflected the high frequency of adverse reactions to typical birch-related food in these groups. Only four patients belonging to the pan-pollen group displayed IgE to profilin Phl p 12/Bet v 2. Patients in the pan-pollen group reported significantly more symptoms to food allergens compared with patients in the two other groups. The most frequently reported symptom was the oral allergy syndrome. Conclusions: Sensitization to grass pollen alone is rare among grass pollen-allergic patients from northern Europe. The majority of patients are in addition sensitized to birch (Bet v 1), which seems to be closely related to their pollen-derived food allergy. The study highlights the advantage of using well-defined allergen molecules for the diagnosis of cross-reactivity between pollen and food allergens.