An investigation of the possible immunological relationship between allergen extracts from birch pollen, hazelnut, potato and apple.

In a retrospective study on selected group of patients, the coincidence of birch pollen allergy and a clinically relevant positive prick test reaction to apples and potatoes was confirmed. Immunochemical comparison using the crossed line immunoelectrophoresis technique (CLIE) confirmed partial identity between birch pollen and hazelnut. By the same method no partial immunological identity between birch pollen and extracts and fresh peel from apples and potatoes was found. However, both apples and potatoes gave rise to non-immunological affinity precipitates. On this basis it is discussed, whether the active agents from apples and potatoes were extremely labile allergens, plant lectins, or low molecular weight substances with a direct or indirect histamine release effect.