Baehler P, Chad Z, Gurbindo C, Bonin A P, Bouthillier L, Seidman E G
Department of Paediatrics, Hôpital Sainte-Justine, Université de Montréal, Canada.
Clin Exp Allergy. 1996 Mar;26(3):254-61.
The clinical manifestations of cow's milk allergy (CMA) are highly variable, and challenges usually identify only immediate, IgE mediated reactions.
To clearly identify CMA of immediate and delayed types using a two-stage, double-blind, placebo-controlled food challenge (DBPCFC), and to prospectively compare the clinical history and analyses of specific IgE antibodies to milk in predicting outcome of DBPCFC.
A total of 69 patients (33 girls, 36 boys) were recruited for study based on a history highly suggestive of CMA and resolution of symptoms on a bovine protein-free diet. After skin-prick tests (SPTs) and search for allergen-specific serum IgE antibodies by enzyme allergosorbent test (EAST), a two-stage DBPCFC was performed over several days.
Of 16 patients (mean age 36.9 months) classified as probable immediate reactors based on the history, 10 (62.5%) had a positive DBPCFC with similar patterns to historical adverse reactions (< or = 2 h after milk exposure). The other 53 (77%) patients (17.3 months) had a history of probable delayed type CMA presenting with predominantly gastrointestimal symptoms from 2 h and up to 6 days after milk exposure. Of these, 15 (28.8%) had a positive DBPCFC, again with a symptom pattern similar to the history. Sensitivity/specificity of SPT was similar to that of EAST for both immediate (70/83% and 62/83% respectively, NS) or delayed (0/97% and 0/97%) CMA confirmed by DBPCFC.
Using our two-stage, prolonged DBPCFC, we clearly identified two groups of children with CMA, reflecting different pathogenesis of either immediate-type IgE-dependent, or delayed-type IgE-independent allergy. Although useful in immediate reactors, IgE antibody determination cannot predict the outcome of DBPCFC in delayed reactors. A thorough clinical history was the most helpful tool to predict the type of response in challenge positive patients.
牛奶过敏（CMA）的临床表现高度多变，而激发试验通常只能识别即刻的、IgE介导的反应。
通过两阶段双盲安慰剂对照食物激发试验（DBPCFC）明确识别即刻型和迟发型CMA，并前瞻性比较临床病史及牛奶特异性IgE抗体分析对DBPCFC结果的预测情况。
基于高度提示CMA的病史以及在无牛蛋白饮食时症状缓解，共招募了69例患者（33例女孩, 36例男孩）进行研究。在皮肤点刺试验（SPT）以及通过酶联免疫吸附试验（EAST）检测变应原特异性血清IgE抗体后，在数天内进行两阶段DBPCFC。
根据病史被归类为可能的即刻反应者的16例患者（平均年龄36.9个月）中，10例（62.5%）DBPCFC呈阳性，其反应模式与既往不良反应相似（牛奶暴露后≤2小时）。其他53例（77%）患者（平均年龄17.3个月）有迟发型CMA病史，主要在牛奶暴露后2小时至6天出现胃肠道症状。其中，15例（28.8%）DBPCFC呈阳性，症状模式同样与病史相似。对于经DBPCFC确诊的即刻型（分别为70/83%和62/83%，无显著差异）或迟发型（均为0/97%）CMA，SPT的敏感性/特异性与EAST相似。
通过我们的两阶段延长DBPCFC，我们明确识别出两组CMA患儿，反映了即刻型IgE依赖型或迟发型IgE非依赖型过敏的不同发病机制。虽然IgE抗体测定对即刻反应者有用，但不能预测迟发反应者的DBPCFC结果。详尽的临床病史是预测激发试验阳性患者反应类型最有用的工具。
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