PERIODATE TREATMENT OF ANISAKIS SIMPLEX ALLERGENS

Anaphylactic reactions after parasitized fish consumption are mediated by an IgE response. However, positive skin tests and specific IgE can also be found in many asymptomatic subjects who recognize a single me dium-mol.-wt. antigen by IgE immunoblot. The study aimed to find out w hether this unspecificity was due to the carbohydrate moieties of para site antigens. Sixty-two patients with suspected parasite allergy, 51 blood donors, 18 bakers, and 38 atopic patients were studied by blotti ng. Parasite proteins were treated with periodate. Several selected se ra were inhibited with a crude wheat extract and fungal amylase. Twelv e patients (19%), eight donors (16%), six bakers (33%), and one atopic patient (3%) recognized a single medium-mol.-wt. band in blotting and should be considered false-positive. This band was periodate-sensitiv e, but specific IgE to this allergen could not be inhibited by a wheat extract nor by fungal amylase and was clinically irrelevant. Diagnosi s of Anisakis simplex hypersensitivity by skin tests and/or specific I gE values should always be confirmed by specific IgE immunoblotting in order to detect the presence of clinically unrelated antibodies direc ted to periodate-sensitive allergens. These allergens are probably not a carbohydrate moiety of a parasite glycoprotein.