IgE binding proteins in honey: discussion on their origin.

ABSTRACT

Pollen proteins, most frequently from Compositae plants, and glandular enzymes from Hymenoptera insects are the only honey allergens involved in every case of honey sensitization reported so far. Surprisingly, we found three patients, all showing the same pattern of honey sensitization with clinical history, cutaneous test and specific IgE clearly positive to honey crude extract but not to the aforementioned components. IgE binding bands, mainly at 54, 46, 17 and 16 kDa, were recognized by the sera of the three patients on blots following electrophoretic separation of a local honey extract under dissociating conditions. Attempts to identify these proteins with the most common honey allergens by means of SDS-PAGE immunoblotting failed, leaving open the question on the origin of protein allergens in cases of honey allergy. Thus, if bee-derived components are not proven to be involved in honey sensitization, other protein sources, such as nectar, should not be disregarded.