Desrosiers M, Proud D, Naclerio R M
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Ann Otol Rhinol Laryngol. 1996 Feb;105(2):146-54. doi: 10.1177/000348949610500210.
We have previously shown that whole body exposure of human subjects to environmental conditions of 37 degrees C and 90% relative humidity (RH) prior to and during nasal challenge with antigen decreases the early response. In this study, we evaluated 1) whether the decreased responses observed resulted from decreased end organ sensitivity to histamine and 2) whether the effect of hot, humid air persisted after the subject exited the hot, humid environment. Ten asymptomatic seasonal allergic subjects and 11 nonallergic subjects were randomized to environmental chamber conditions of either 20 degrees C, 30% RH or 37 degrees C, 90% RH for 1 hour prior to and during performance of a nasal challenge with histamine. Twenty-two hours after exiting the environmental chamber, the allergic subjects were challenged with antigen. During both chamber conditions, histamine challenge was associated with a significant increase in all measured parameters compared to sham challenge, except for the sensations of pruritus and congestion. The response to histamine challenge was not different under the two experimental conditions or between allergic and nonallergic subjects. Following both exposure conditions, allergen challenge was associated with an increase in all measured parameters compared to sham challenge, with no significant difference between the two conditions. Exposure to 37 degrees C, 90% RH minimally affects the response to nasal challenge with histamine, and thus, the previously reported decreases in the early nasal response to antigen may primarily result from reduction in mast cell activation. The effect on antigen does not persist 22 hours after exposure.
我们之前已经表明，在抗原鼻激发试验之前及试验期间，让人体受试者全身暴露于37摄氏度和90%相对湿度（RH）的环境条件下，会降低早期反应。在本研究中，我们评估了：1）观察到的反应降低是否是由于终末器官对组胺的敏感性降低所致；2）在受试者离开湿热环境后，湿热空气的影响是否仍然存在。10名无症状的季节性过敏受试者和11名非过敏受试者在进行组胺鼻激发试验之前及试验期间，被随机分配到20摄氏度、30%RH或37摄氏度、90%RH的环境舱条件下1小时。离开环境舱22小时后，对过敏受试者进行抗原激发试验。在两种舱内条件下，与假激发试验相比，组胺激发试验与所有测量参数的显著增加相关，但瘙痒和充血感除外。在两种实验条件下，以及在过敏和非过敏受试者之间，对组胺激发试验的反应没有差异。在两种暴露条件之后，与假激发试验相比，过敏原激发试验与所有测量参数的增加相关，两种条件之间没有显著差异。暴露于37摄氏度、90%RH对组胺鼻激发试验的反应影响最小，因此，之前报道的抗原早期鼻反应降低可能主要是由于肥大细胞活化减少所致。暴露后22小时，对抗原的影响不再持续。
