Asthma and Allergic Diseases Center, University of Virginia Health System, Charlottesville, VA, USA.
J Allergy Clin Immunol. 2011 May;127(5):1286-93.e6. doi: 10.1016/j.jaci.2011.02.019. Epub 2011 Mar 31.
In 2009, we reported a novel form of delayed anaphylaxis to red meat that is related to serum IgE antibodies to the oligosaccharide galactose-α-1,3-galactose (alpha-gal). Most of these patients had tolerated meat for many years previously. The implication is that some exposure in adult life had stimulated the production of these IgE antibodies.
We sought to investigate possible causes of this IgE antibody response, focusing on evidence related to tick bites, which are common in the region where these reactions occur.
Serum assays were carried out with biotinylated proteins and extracts bound to a streptavidin ImmunoCAP.
Prospective studies on IgE antibodies in 3 subjects after tick bites showed an increase in levels of IgE to alpha-gal of 20-fold or greater. Other evidence included (1) a strong correlation between histories of tick bites and levels of IgE to alpha-gal (χ(2) = 26.8, P < .001), (2) evidence that these IgE antibodies are common in areas where the tick Amblyomma americanum is common, and (3) a significant correlation between IgE antibodies to alpha-gal and IgE antibodies to proteins derived from A americanum (r(s) = 0.75, P < .001).
The results presented here provide evidence that tick bites are a cause, possibly the only cause, of IgE specific for alpha-gal in this area of the United States. Both the number of subjects becoming sensitized and the titer of IgE antibodies to alpha-gal are striking. Here we report the first example of a response to an ectoparasite giving rise to an important form of food allergy.
2009 年，我们报道了一种新型的延迟性对红肉过敏的现象，这种过敏与血清 IgE 抗体针对寡糖半乳糖-α-1,3-半乳糖（alpha-gal）有关。这些患者中的大多数在此之前已经多年耐受肉类。这意味着在成年生活中，某些暴露会刺激这些 IgE 抗体的产生。
我们试图研究这种 IgE 抗体反应的可能原因，重点关注与这些反应发生地区常见的蜱叮咬有关的证据。
使用生物素化蛋白和与链霉亲和素结合的提取物进行血清测定。
对 3 例蜱叮咬后 IgE 抗体的前瞻性研究显示，IgE 对 alpha-gal 的水平增加了 20 倍或更多。其他证据包括：（1）蜱叮咬史与 IgE 对 alpha-gal 的水平之间存在强烈相关性（χ²=26.8，P<.001）；（2）这些 IgE 抗体在常见蜱虫 Amblyomma americanum 的地区很常见；（3）IgE 对 alpha-gal 的抗体与源自 A. americanum 的蛋白质的 IgE 抗体之间存在显著相关性（r(s)=0.75，P<.001）。
这里提供的结果提供了证据表明蜱叮咬是美国这一地区 IgE 特异性针对 alpha-gal 的原因，可能是唯一原因。致敏的受试者数量和对 alpha-gal 的 IgE 抗体滴度都很显著。这里我们报告了首例对寄生虫的反应导致重要食物过敏的例子。
