[A case of an allergic reaction due to Anisakis simplex possibly after the ingestion of squid--successful detection of four A. simplex allergens, Ani s 1, Ani s 2, Ani s 12 and troponin C-like protein].

A 62-year-old man ingested dressed salmon and its roe (ikura) and grilled mackerel and one hour later further ingested raw tuna and squid as an evening meal at a bar. Soon after the ingestion of raw seafood, he showed wheals, loss of consciousness and low blood pressure. Specific serum IgE to the nematode Anisakis simplex was positive but those to some seafoods were negative. Moreover, a skin prick test using the crude extract was positive for A. simplex but negative for the seafoods, which he ingested on the day of the above episode. When the A. simplex extract was analyzed by IgE-binding immunoblot analysis using the patient serum, two highly intense protein bands were recognized at 18 and 17 kDa, one intense band at 35 kDa and two weak bands at 28 and 26 kDa. ELISA with 11 natural or recombinant A. simplex allergens (Ani s 1-6, 8, 9, 11 and 12 and troponin C-like protein) showed that the patient serum strongly reacted to Ani s 1 and Ani s 12 and weakly to Ani s 2 and troponin C-like protein. Based on these results, he was diagnosed as IgE-mediated A. simplex allergy due to four allergens (Ani s 1, Ani s 2, Ani s 12 and troponin C-like protein), possibly infested in the raw squid which he had ingested just before manifestation of allergic reactions.