Isolation of Ani s 5, an excretory–secretory and highly heat-resistant allergen useful for the diagnosis of Anisakis larvae sensitization

Allergens Ani s 1 and Ani s 4 have demonstrated their utility for the diagnosis of the sensitization to larvae of the genus Anisakis. The aim was to determine the number of patients with compatible clinical history, who did not recognize Ani s 1 and Ani s 4, and characterize the allergens responsible for their sensitization. Eighty-four patients were studied by CAP and immunoglobulin E (IgE) immunoblotting. The 12% of the patients recognized allergens different from Ani s 1 and Ani s 4, being half sensitized to a heat-resistant 15-kDa allergen, which was isolated by ethanol fractionation, followed by a hydroxyapatite chromatography and a reversed-phase high-performance liquid chromatography and identified by its amino terminal sequence as Ani s 5. A total of 41 of the 84 patients studied (49%) showed specific IgE to Ani s 5 that was detected among the excretory–secretory products and immunohistochemically located at the excretory gland, ventriculus, and the luminal surface of the intestinal epithelium of the larvae.