Subcutaneous immunotherapy (SCIT) is the standard approach for treating patients with sensitizations to aeroallergens. However, immunotherapy can trigger severe systemic reactions if delivered inappropriately or to high risk patients. We sought to characterize and quantify SCIT systemic reactions requiring epinephrine administration during a 6-year period in a Canadian setting following the recommendations for components and dosages published in the 2010 Canadian Society of Allergy and Clinical Immunology (CSACI) Immunotherapy Manual. A single centre retrospective chart review was performed for all patients with systemic reactions to subcutaneous immunotherapy requiring intramuscular epinephrine injection between January 2011 and October 2017. Each systemic reaction requiring epinephrine was reviewed for baseline patient characteristics, details of the reaction, and reaction severity. Research ethics approval was obtained through McMaster University. 28 of 380 patients experienced a systemic reaction requiring epinephrine administration, with an incidence rate of 1 per 1,047 injection visits (0.095%). 26 of the 28 reactions occurred within the mandatory 30-minute observation period post allergen immunotherapy. Of the 28 patients that experienced a systemic reaction to SCIT, 11 patients had asthma and 5 patients had a history of possible food allergy. All of the systemic reactions occurred during injections from vial number 4, and five patients reacted to their first shot of a re-ordered extract. 10 of the 28 patients required more than one intramuscular injection of epinephrine, and 20 of 28 patients were transferred to the hospital by ambulance. This is the first Canadian study to review patients with systemic reactions to subcutaneous immunotherapy. Several best practice methods were employed throughout the study to optimize subcutaneous delivery of immunotherapy extract, and our recorded per injection incidence rate for systemic reactions was comparable or below the rate published in similar studies. The recommendations in the CSACI Immunotherapy Manual provide an approach to standardizing prescriptions for SCIT to maximize immunotherapy efficacy and reduce the risk of systemic reactions, though similar studies in larger multicenter settings are needed to confirm these observations. These observations provide important objective information to clinicians about the potential risks for systemic reactions in patients considering SCIT.

中文翻译：

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皮下免疫疗法全身反应的单中心回顾性研究

皮下免疫疗法（SCIT）是治疗对气敏原致敏的患者的标准方法。但是，如果不适当地递送给高危患者，免疫疗法会引发严重的全身反应。在2010年加拿大变态反应和临床免疫学会（CSACI）免疫疗法手册中公布的成分和剂量建议后，我们试图在加拿大的环境中表征和量化需要在6年内使用肾上腺素的SCIT系统反应。在2011年1月至2017年10月之间，对所有需要肌肉注射肾上腺素的皮下免疫治疗的全身反应的患者进行了单中心回顾性图表回顾。对每个需要肾上腺素的全身反应进行了基线患者特征，反应的详细信息和反应的严重性。研究伦理学的批准是通过麦克马斯特大学获得的。380名患者中有28名发生全身性反应，需要使用肾上腺素，每1047次注射访视的发生率为1（0.095％）。在过敏原免疫治疗后的30分钟强制观察期内，发生了28种反应中的26种。在对SCIT发生全身反应的28位患者中，有11位患有哮喘，有5位有食物过敏史。所有的全身反应都发生在从4号小瓶注射时，五名患者对其重新订购的提取物的第一剂反应。28名患者中有10名需要肌肉注射一次肾上腺素，而28名患者中有20名通过救护车转入了医院。这是加拿大第一项对皮下免疫疗法有全身反应的患者进行回顾的研究。在整个研究过程中，采用了几种最佳实践方法来优化免疫疗法提取物的皮下递送，我们记录的每次注射的全身性反应发生率可比或低于类似研究中公布的比率。CSACI免疫疗法手册中的建议提供了一种标准化SCIT处方的方法，以最大化免疫疗法的功效并降低全身反应的风险，尽管需要在较大的多中心环境中进行类似的研究来确认这些观察结果。这些观察结果为临床医生提供了关于考虑使用SCIT的患者全身反应的潜在风险的重要客观信息。