Food allergy: Specific binding of IgE antibodies from plant food sensitized individuals to carbohydrate epitopes

The presence of anti‐carbohydrate immunoglobulin E (IgE) antibodies was investigated in a group of 54 patients who were sensitive to at least two pollen species and at least five vegetable foods. Enzyme‐linked immunosorbent assays (ELISAs) and ELISA inhibition assays were performed with immobilized food‐related oligosaccharides (e.g. stachyose from legumes) and extracts of plant gums (e.g. gum arabic), as well as with allergen extracts from apples, celery and other fruits and vegetables. Furthermore, a combined procedure of immunoblotting and periodate treatment was applied to identify the epitope nature of glycans from vegetable food glycoproteins. The results suggested that 12/54 of the sera contained IgE antibodies against carbohydrate structures. The antibodies were also found to be highly cross‐reactive. For six patients, galactose may be an important epitope. The clinical relevance of the phenomenon requires further investigation.