Background

The direct-instillation nasal allergen challenge (NAC) and the environmental exposure chamber (EEC) are 2 methods of conducting controlled allergen provocations. The clinical and biological comparability of these methods has not been thoroughly investigated.

Objective

We sought to compare clinical and immunologic responses to cat allergen in NAC versus EEC.

Methods

Twenty-four participants were randomized to receive either NAC followed by a 2-day challenge in an EEC or a 2-day challenge in an EEC followed by NAC. Challenges were separated by 28-day washout periods. We measured total nasal symptom scores, peak nasal inspiratory flow, nasal (0-8 hours) and serum cytokines, serum antibodies, peripheral blood antigen-specific T lymphocytes, and gene expression in nasal scrapings. The primary outcome was the total nasal symptom score area under the curve for the first 3 hours after allergen exposure in NAC or after initiation of exposure in EEC.

Results

Both challenges increased IL-5 and IL-13 in nasal fluids and serum and resulted in altered nasal cell expression of gene modules related to mucosal biology and transcriptional regulation. Changes in gene modules, more so than cytokine measurements, showed significant associations with total nasal symptom score and peak nasal inspiratory flow. Overall, EEC exposure generated larger responses and more early terminations compared with NAC. Although the 2 challenges did not correlate in symptom magnitude or temporality, striking correlations were observed in cytokine levels.

Conclusions

Although clinical outcomes of NAC and EEC were temporally different and nonequivalent in magnitude, immunologic responses were similar. Selection of a particular allergen challenge method should depend on considerations of study objectives and cost.

中文翻译：

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鼻过敏原挑战和环境暴露室挑战：一项比较对猫过敏原的临床和生物学反应的随机试验。

背景

直接滴注鼻过敏原挑战 (NAC) 和环境暴露室 (EEC) 是进行受控过敏原激发的两种方法。这些方法的临床和生物学可比性尚未得到彻底研究。

客观的

我们试图比较 NAC 与 EEC 对猫过敏原的临床和免疫反应。

方法

24 名参与者随机接受 NAC，然后在 EEC 中进行为期 2 天的挑战，或者在 EEC 中进行 2 天的挑战，然后是 NAC。挑战以 28 天的清除期分开。我们测量了鼻部症状总评分、鼻吸气峰流量、鼻腔（0-8 小时）和血清细胞因子、血清抗体、外周血抗原特异性 T 淋巴细胞和鼻刮屑中的基因表达。主要结果是在 NAC 中过敏原暴露后或在 EEC 中开始暴露后前 3 小时的曲线下总鼻症状评分面积。

结果

这两项挑战都增加了鼻液和血清中的 IL-5 和 IL-13，并导致与粘膜生物学和转录调控相关的基因模块的鼻细胞表达发生改变。与细胞因子测量相比，基因模块的变化显示出与鼻部症状总评分和鼻吸气峰值流量的显着关联。总体而言，与 NAC 相比，EEC 暴露产生了更大的响应和更早的终止。尽管这 2 个挑战在症状大小或时间上没有相关性，但在细胞因子水平上观察到了惊人的相关性。

结论

尽管 NAC 和 EEC 的临床结果在时间上不同且幅度不相等，但免疫反应相似。特定过敏原激发方法的选择应取决于研究目标和成本的考虑。