From the Department of Internal Medicine, Division of Rheumatology, Allergy & Immunology, University of California San Diego, San Diego, CA.
Department of Biology, Illinois State University, Normal, Il.
Allergy Asthma Proc. 2020 Jul 1;41(4):290-295. doi: 10.2500/aap.2020.41.200030.
The booklouse, Liposcelis bostrychophila, is a potent environmental allergen clinically associated with rhinoconjunctivitis and asthma. Despite its known infestation of grain products, anaphylaxis from ingestion of this organism has, to our knowledge, not been previously reported. We present the case of a 44-year-old woman who developed anaphylaxis to ingested oats and rice shown to be contaminated with L. bostrychophila. The objective was to isolate a distinct antigen from L. bostrychophila implicated in a case of unexplained anaphylaxis. In vitro studies were obtained for relevant ingested materials and aeroallergens. Skin-prick testing (SPT) was performed with standard extracts, contaminated oats, fresh oats, and crushed L. bostrychophila. Western blots were conducted using subject and control serum to detect specific immunoglobulin E (IgE) against the grains and L. bostrychophila extract. Competitive inhibition immunoblotting was used to assess specificity of IgE binding. In vitro studies and SPT were notable for positive responses to dust mite and flour contaminated by L. bostrychophila, along with contaminated oats. Testing results for fresh oat and rice were negative. Immunoblots that used the subject's serum revealed a strongly positive band in the contaminated oat and rice extracts at 24 kD, whereas dust-mite extract yielded a single 14-kD band. Isolated L. bostrychophila extract also yielded a 24-kD band. Competitive inhibition experiments demonstrated that the 24-kD band in the contaminated oat extract was immunologically distinct from the 14-kD dust-mite band. Our case highlights the importance of considering L. bostrychophila as a potential culprit for unexplained anaphylaxis due to ingested grain products. Given the ubiquitous presence of this insect, we suspect that this may be a more common problem than previously recognized.
书虱，即嗜虫书虱（Liposcelis bostrychophila），是一种强有力的环境过敏原，临床上与鼻结膜炎和哮喘有关。尽管已知其会侵害谷物产品，但据我们所知，这种生物摄入引起过敏反应的情况以前尚未有报道。我们介绍了一位 44 岁女性的病例，她因摄入被嗜虫书虱污染的燕麦和大米而出现过敏反应。目的是从嗜虫书虱中分离出一种与不明原因过敏反应有关的特定抗原。进行了体外研究，以获取相关摄入物和空气过敏原的信息。进行了皮肤点刺试验（SPT），使用标准提取物、受污染的燕麦、新鲜燕麦和压碎的嗜虫书虱进行检测。使用患者和对照血清进行 Western blot 检测，以检测针对谷物和嗜虫书虱提取物的特异性免疫球蛋白 E（IgE）。竞争性抑制免疫印迹用于评估 IgE 结合的特异性。体外研究和 SPT 结果表明，对尘螨和受嗜虫书虱污染的面粉，以及受污染的燕麦有阳性反应。新鲜燕麦和大米的测试结果为阴性。使用患者血清进行的免疫印迹显示，受污染的燕麦和大米提取物在 24 kD 处有一条强烈的阳性带，而尘螨提取物则产生一条单一的 14-kD 带。分离的嗜虫书虱提取物也产生了 24-kD 带。竞争性抑制实验表明，受污染的燕麦提取物中 24-kD 带在免疫学上与 14-kD 尘螨带不同。我们的病例强调了由于摄入谷物产品而将嗜虫书虱视为不明原因过敏反应的潜在罪魁祸首的重要性。鉴于这种昆虫无处不在，我们怀疑这可能是一个比以前认识到的更为普遍的问题。
