419 IGE-mediated Responses Towards Fish Parasite Anisakis, Crab and House Dust Mite in Norwegian Shrimp Allergic Individuals

BACKGROUND: The present study investigated to what extent shrimp allergic individuals were IgE-sensitized to anisakis, crab and house dust mite and whether tropomyosin was responsible for IgE cross-reactivity. METHODS: 29 Individuals with self reported shrimp allergy were recruited by advertisements in local and national news-papers in Norway. Anamnesis was taken, skin prick tests (SPT) were performed and positive responders to shrimp were studied further with basophile activation test (BAT), ImmunoCAP analyses and western blotting. RESULTS: Of the 29 persons studied, 10 (34%) had positive SPT against shrimp and house dust mite, 9 (31%) against shrimp tropomyosin and 3 (10%) against anisakis. Individuals with positive SPT to shrimp all showed positive basophilic responses to house dust mite, while 43% responded to shrimp, 25% to anisakis and 36% to crab in BAT. Moreover, SPT, BAT as well as ImmunoCAP analyses showed a positive correlation of IgE-reactivity between anisakis and shrimp, house dust mite and crab. Immunoblot studies indicated that these responses are not completely explained by cross-reactivity towards tropomyosin. CONCLUSIONS: The current study indicates a positive correlation between IgE-mediated reactions to shrimp, anisakis, house dust mite and crab, which may not be completely explained by cross-reactivity against tropomyosin.