Allergen cross-reactivities occur when IgE antibodies, originally raised against a specific allergen, bind to identical or highly similar surface areas of another related allergen. It is a commonly held view that cross-reactivity requires more than 70% sequence identity, while proteins that share less than 50% sequence identity are rarely cross-reactive. This also implies that cross-reactive proteins have a similar 3D fold and belong to the same protein family. At first, the existence of cross-reactivity between non-homologous allergens was not expected because it was contrary to the above described concepts. Now, several lines of evidence demonstrate that IgE cross-reactivity also exists between unrelated allergens. In this Editorial, we aim to summarize the existing literature on IgE cross-reactivity between non-homologous allergens.

中文翻译：

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非同源过敏原的交叉反应

当最初针对特定过敏原产生的 IgE 抗体与另一种相关过敏原的相同或高度相似的表面积结合时，就会发生过敏原交叉反应。人们普遍认为，交叉反应需要超过 70% 的序列同一性，而序列同一性低于 50% 的蛋白质很少发生交叉反应。这也意味着交叉反应蛋白具有相似的 3D 折叠并且属于相同的蛋白质家族。起初，非同源变应原之间存在交叉反应是意料之中的，因为它与上述概念相反。现在，有几条证据表明不相关的过敏原之间也存在 IgE 交叉反应。在本社论中，我们旨在总结有关非同源过敏原之间 IgE 交叉反应性的现有文献。