Zeller Sabine, Glaser Andreas G, Vilhelmsson Monica, Rhyner Claudio, Crameri Reto
Swiss Institute of Allergy and Asthma Research, Davos, Switzerland.
Int Arch Allergy Immunol. 2008;145(2):87-93. doi: 10.1159/000108133. Epub 2007 Sep 7.
Immunoglobulin E (IgE) reactivity to self antigens is well established in vitro by ELISA, inhibition ELISA, Western blot analyses and T cell proliferation experiments. In vivo, IgE-binding self antigens are able to elicit strong type I reactions in sensitized individuals and, in the case of human manganese superoxide dismutase, to elicit eczematous reactions on healthy skin areas of patients suffering from atopic eczema. The reactions against self antigens sharing structural homology with environmental allergens can be plausibly explained by molecular mimicry between common B cell epitopes. For the second class of IgE-binding self antigens without sequence homology to known allergens, it is still unclear if the structures are able to induce a B cell switch to IgE production, or if the reactivity is due to sequence similarity shared with not yet detected environmental allergens. However, in all cases, cross-reactivity is never complete, indicating either a lower affinity of IgE antibodies to self allergens than to the homologous environmental allergens or the presence of additional B cell epitopes on the surface of the environmental allergens, or both. Increasing evidence shows that self allergens could play a decisive role in the exacerbation of long-lasting atopic diseases. However, the only observation supporting a clinical role of IgE-mediated autoreactivity is confined to the fact that IgE levels against self antigens correlate with disease severity.
通过酶联免疫吸附测定（ELISA）、抑制性ELISA、蛋白质印迹分析和T细胞增殖实验，已在体外充分证实免疫球蛋白E（IgE）对自身抗原的反应性。在体内，与IgE结合的自身抗原能够在致敏个体中引发强烈的I型反应，就人类锰超氧化物歧化酶而言，能够在患有特应性皮炎的患者的健康皮肤区域引发湿疹反应。针对与环境过敏原具有结构同源性的自身抗原的反应，可以通过常见B细胞表位之间的分子模拟来合理地解释。对于第二类与已知过敏原无序列同源性的IgE结合自身抗原，其结构是否能够诱导B细胞转换为产生IgE，或者其反应性是否归因于与尚未检测到的环境过敏原共有的序列相似性，目前仍不清楚。然而，在所有情况下，交叉反应性都不完全，这表明要么IgE抗体对自身过敏原的亲和力低于对同源环境过敏原的亲和力，要么环境过敏原表面存在额外的B细胞表位，或者两者兼而有之。越来越多的证据表明，自身过敏原可能在持续性特应性疾病的加重中起决定性作用。然而，支持IgE介导的自身反应性具有临床作用的唯一观察结果仅限于针对自身抗原的IgE水平与疾病严重程度相关这一事实。
