Sicherer S H, Wood R A, Eggleston P A
Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, USA.
J Allergy Clin Immunol. 1997 Jun;99(6 Pt 1):798-805. doi: 10.1016/s0091-6749(97)80014-0.
Why allergic subjects may have asthma or rhinitis off allergen exposure remains unclear.
This study was carried out to compare airway responses during environmental allergen challenge (EAC) with quantitative allergen provocation challenges of the upper and lower airways.
Thirteen subjects with allergy to cats underwent EAC to cats. Lower airway responses during EAC were compared with bronchoprovocation with allergen. Nasal mucosal challenge with allergen-soaked disks were compared with EAC nasal responses. Nonspecific bronchial reactivity was assessed with methacholine; allergen sensitivity was assessed by skin prick tests, RAST, and end-point skin titration.
During EAC, the maximal fall in FEV1 ranged from 6% to 57% (median, 18%) and correlated closely with allergen bronchoprovocation PD20 (Spearman's correlation coefficient [Rs] = -0.85, p < 0.0002). EAC asthmatic responses and allergen bronchoprovocation correlated with methacholine PD20 (Rs = -0.85, p = 0.0002 and Rs = 0.83, p = 0.0004, respectively). Nasal provocation and EAC nasal responses correlated with each other but not with lower airway responses. On the basis of EAC and allergen bronchoprovocation responses, seven participants with asthma were identified. This group was significantly more sensitive to inhaled methacholine but was similar to the nonasthmatic group in IgE-mediated sensitivity and nasal responses.
The lower respiratory tract is less responsive to allergic and nonallergic stimuli in persons with allergic rhinitis. In persons with asthma during EAC, the response to nebulized cat allergen is also abnormal and correlates closely with their abnormal responsiveness to nonimmunologic stimuli.
过敏患者在脱离过敏原暴露后仍可能患有哮喘或鼻炎，其原因尚不清楚。
本研究旨在比较环境过敏原激发试验（EAC）期间的气道反应与上、下气道定量过敏原激发试验的反应。
13名对猫过敏的受试者接受了针对猫的EAC。将EAC期间的下气道反应与过敏原支气管激发试验进行比较。将用过敏原浸泡的圆盘进行的鼻黏膜激发试验与EAC鼻反应进行比较。用乙酰甲胆碱评估非特异性支气管反应性；通过皮肤点刺试验、放射变应原吸附试验（RAST）和终点皮肤滴定评估过敏原敏感性。
在EAC期间，第一秒用力呼气容积（FEV1）的最大下降幅度为6%至57%（中位数为18%），且与过敏原支气管激发试验的PD20密切相关（斯皮尔曼相关系数[Rs]= -0.85，p<0.0002）。EAC哮喘反应和过敏原支气管激发试验与乙酰甲胆碱PD20相关（Rs分别为 -0.85，p = 0.0002和Rs = 0.83，p = 0.0004）。鼻激发试验和EAC鼻反应相互相关，但与下气道反应无关。根据EAC和过敏原支气管激发试验反应，确定了7名哮喘参与者。该组对吸入乙酰甲胆碱明显更敏感，但在IgE介导的敏感性和鼻反应方面与非哮喘组相似。
变应性鼻炎患者的下呼吸道对变应性和非变应性刺激的反应性较低。在EAC期间患有哮喘的患者中，对雾化猫过敏原的反应也异常，且与其对非免疫性刺激的异常反应性密切相关。
