LABORATORY DETERMINATIONS IN ANISAKIS SIMPLEX ALLERGY

Background: Anaphylactic reactions caused by the fish nematode, Anisak is simplex, after ingestion of parasitized fish, have been described. Objective: This study was undertaken to confirm, by histamine release tests, that A. simplex is able to trigger IgE-mediated reactions and t o describe the serologic profiles in this sensitization. Methods: Twel ve patients who had anaphylactic symptoms after ingestion of cooked fi sh and positive prick test results and determinations of IgE to A. sim plex were studied by indirect IgG ELISA and IgG and IgE immunoblotting . Sera from subjects parasitized with other nematodes, patients with f ish allergy, and healthy donors were induced as controls. A histamine release test was performed in a representative case. Results: IgE immu noblotting was a specific test to detect A. simplex allergy. IgE-react ing bands were found in serum samples from 11 of our patients. Specifi c IgG antibodies were found by ELISA and immunoblotting, but this resp onse was less specific. Histamine release was positive with A. simplex extract and negative with fish. Conclusion: A specific and intense im mune response to an A. simplex extract was found in our patients. A. s implex is able to elicit anaphylactic reactions, and A. simplex allerg y should be suspected in patients with allergic symptoms after ingesti on of fish. A positive prick test response to A. simplex and negative response to fish is good indication for a diagnosis of A. simplex alle rgy.