A DOUBLE-BLIND-STUDY OF SYMPTOM PROVOCATION TO DETERMINE FOOD SENSITIVITY
A DOUBLE-BLIND-STUDY OF SYMPTOM PROVOCATION TO DETERMINE FOOD SENSITIVITY
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DOI：
10.1056/nejm199008163230701
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发表时间：
1990-08-16
影响因子：
158.5
通讯作者：
GREENBERG, MH
中科院分区：
文献类型：
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作者：
JEWETT, DL;FEIN, G;GREENBERG, MH
背景资料：有些人声称，通过皮内注射可疑过敏原的提取物来重现相关症状，可以最好地识别食物敏感性。不同剂量的过敏原被认为可以“中和”反应。研究方法：为了评估症状激发的有效性，我们进行了一项双盲研究，该研究在七位医生的办公室进行，他们是这项技术的支持者，并在其使用方面有经验。由同一技术人员使用与先前认为在揭盲试验期间引起症状的浸提液相同的浸提液（用相同生理盐水稀释液稀释），在20个阶段中对18例患者进行了试验（2例患者进行了两次试验）。在每个阶段，以随机顺序注射3次浸提液和9次稀释液。评估的症状包括鼻塞、口干、恶心、疲劳、头痛和感觉定向障碍或抑郁。无患者有哮喘或过敏史。 结果如下：患者对活性和对照注射的反应是不可区分的，阳性反应的发生率也是如此：27%的活性注射（60次中的16次）被患者判断为活性物质，24%的对照注射（180次中的44次）也是如此。无论注射的是疑似过敏原还是生理盐水，一些医生在反应后给予的治疗症状的中和剂量都同样有效。判断注射为活性的速率在实验期间保持相对恒定，由于中和或习惯化，反应速率没有重大变化。结论：当在双盲条件下评估症状的激发以确定食物敏感性时，这种类型的测试以及基于“中和”这种反应的治疗似乎缺乏科学有效性。对注射提取物的积极反应的频率似乎是暗示和机会的结果。
Background: Some claim that food sensitivities can best be identified by intradermal injection of extracts of the suspected allergens to reproduce the associated symptoms. A different dose of an offending allergen is thought to "neutralize" the reaction. Methods: To assess the validity of symptom provocation, we performed a double-blind study that was carried out in the offices of seven physicians who were proponents of this technique and experienced in its use. Eighteen patients were tested in 20 sessions (two patients were tested twice) by the same technician, using the same extracts (at the same dilutions with the same saline diluent) as those previously thought to provoke symptoms during unblinded testing. At each session three injections of extract and nine of diluent were given in random sequence. The symptoms evaluated included nasal stuffiness, dry mouth, nausea, fatigue, headache, and feelings of disorientation or depression. No patient had a history of asthma or anaphylaxis. Results: The responses of the patients to the active and control injections were indistinguishable, as was the incidence of positive responses: 27 percent of the active injections (16 of 60) were judged by the patients to be the active substance, as were 24 percent of the control injections (44 of 180). Neutralizing doses given by some of the physicians to treat the symptoms after a response were equally efficacious whether the injection was of the suspected allergen or saline. The rate of judging injections as active remained relatively constant within the experimental sessions, with no major change in the response rate due to neutralization or habituation. Conclusions: When the provocation of symptoms to identify food sensitivities is evaluated under double-blind conditions, this type of testing, as well as the treatments based on "neutralizing" such reactions, appears to lack scientific validity. The frequency of positive responses to the injected extracts appears to be the result of suggestion and chance.