岡本 薫

Objectives: Fish roe is a common allergen in Japan. We have previously reported that although immunoglobulin (IgE) from patients with salmon roe (SR) or pollock roe (PR) allergies cross-react, 70% of patients with SR allergy can consume PR without developing any symptoms. However, a correlation between clinical cross-reactivity and serological cross-reactivity remains to be demonstrated. Methods: Serum samples were collected from 15 patients with SR allergy who had consumed cooked PR previously. Among these volunteers, four had experienced immediate symptoms after consuming cooked PR, while the others had exhibited no symptoms of PR allergy. A competitive enzyme-linked immunosorbent assay (ELISA) was performed to analyze the serological cross-reactivity with SR and PR. Immunoblotting inhibition assays were performed using serum samples that had been pre-incubated with SR or PR extracts. Results: In ELISAs, binding to SR was inhibited by >50% when the serum samples from patients with both SR and PR allergies were pre-incubated with PR extract (p=0.0256). In immunoblots, pre-incubation of serum samples with PR extract inhibited detection of the 16-kDa protein, which likely corresponds to the major SR allergen beta' component, significantly more for samples from patients with both SR and PR allergies (100%) than for samples from those with only an SR allergy (18.2%) (p=0.011). Conclusions: The superior competitive binding of the sera from patients with both SR and PR allergies to PR compared with that to SR may induce clinical cross-reactivity between SR and PR.

【背景】イクラアレルギー患者のどの程度が、他魚種卵に対してアレルギー症状を呈するか臨床的な検討はされていない。【方法】イクラアレルギー患者のカルテ記載内容から、タラコや子持ちシシャモのアレルギー合併率について後方視的に検討した。【対象】イクラアレルギーの診断は、特異的IgE抗体陽性でイクラ摂取による即時型反応の明らかな既往があるか、ない場合は経口負荷試験で診断された児とした。タラコ、子持ちシシャモアレルギーに関しても同様で明らかな病歴もしくは経口負荷試験から判断した。【結果】イクラアレルギー患者25人中、タラコと子持ちシシャモの摂取歴がある者はそれぞれ16人と18人で、そのうちアレルギー症状を呈した者はタラコで4人(25%)、子持ちシシャモで2人(11%)であった。【結論】イクラアレルギーの多くは他魚卵を安全に摂取できることがわかった。このことから、必要に応じた他魚卵の経口負荷試験の実施が望まれる。(著者抄録)