Background

Birch pollen is a prevalent aeroallergen during the springtime allergy season. In field studies, variable allergen exposure and environmental factors can affect data quality while environmental exposure units (EEUs) deliver controlled, standardized, and reproducible allergen exposures.

Objective

To inform study design for EEU trials evaluating antiallergic therapies.

Methods

In this prospective study, 76 participants with birch allergy experienced 3 exposures to birch pollen: (1) an out-of-season EEU challenge (two 3-hour sessions on consecutive days); (2) a natural seasonal exposure; and (3) an in-season EEU challenge (3-hour exposure for 2 weeks after birch pollen season initiation).

Results

The total nasal symptom score, total ocular symptom score, and total symptom score (TSS = total nasal symptom score plus total ocular symptom score) were assessed every 30 minutes and daily during EEU and natural exposures. A high association between TSSs and day 2 of the out-of-season and in-season EEU challenges was noted, with a good association between the maximum TSS during the natural and in-season EEU challenges, and natural season and day 2 of the out-of-season EEU challenge (P < .001 for all). Participants had higher maximum change from the baseline TSS during day 2 of the out-of-season EEU challenge (12.4) vs the following: (1) first day (9.8); (2) in-season EEU challenge (8.4); and (3) natural seasonal exposure (7.6) (P < .001 for all).

Conclusion

A strong association was seen between the presence of allergy symptoms and exposure to birch pollen in the EEU (maximum change in symptom scores during day 2) and in the field. A hybrid trial design may be useful to demonstrate the clinical efficacy of novel antiallergic therapies requiring fewer participants and shorter timelines and expediting treatment availability.

中文翻译：

---

环境暴露单元模拟自然季节性桦树花粉暴露，同时最大限度地改变过敏症状

背景

桦木花粉是春季过敏季节流行的空气过敏原。在现场研究中，可变的过敏原暴露和环境因素会影响数据质量，而环境暴露单元 (EEU) 提供受控、标准化和可重复的过敏原暴露。

客观的

为评估抗过敏疗法的 EEU 试验的研究设计提供信息。

方法

在这项前瞻性研究中，76 名桦树过敏参与者经历了 3 次桦树花粉暴露：（1）反季节 EEU 挑战（连续几天两次 3 小时的会议）；(2) 自然季节性暴露；(3) 季节性 EEU 挑战（在桦树花粉季节开始后 2 周内暴露 3 小时）。

结果

在 EEU 和自然暴露期间，每 30 分钟和每天评估一次总鼻部症状评分、总眼部症状评分和总症状评分（TSS = 总鼻部症状评分加总眼部症状评分）。注意到 TSS 与反季节和季节性 EEU 挑战的第 2 天之间存在高度关联，自然和季节性 EEU 挑战期间的最大 TSS 与自然季节和第 2 天之间存在良好关联反季节 EEU 挑战（所有P < .001）。在反季节 EEU 挑战 (12.4) 的第 2 天，参与者从基线 TSS 的最大变化 (12.4) 与以下情况相比：(1) 第一天 (9.8)；(2) 季节性 EEU 挑战 (8.4)；(3) 自然季节性暴露 (7.6)（所有P < .001）。

结论

在 EEU（第 2 天症状评分的最大变化）和野外发现过敏症状的存在与接触桦树花粉之间存在很强的关联。混合试验设计可能有助于证明新型抗过敏疗法的临床疗效，需要更少的参与者和更短的时间，并加快治疗的可用性。