Effects of Nitric Acid Vapor and Ozone on the Response to Inhaled Allergen in211 Allergic Asthmatic Subjects

摘要

Epidemiologic data suggest that ozone exposure may increase the risk of asthma211u001eexacerbation, although controlled human exposure studies are inconclusive. Acidic 211u001epollutants may influence responses to ozone. This study investigates responses to 211u001einhaled allergen in allergic a asthmatic subjects exposed to (Phase I) 0.2 ppm 211u001eozone and filtered air, and (Phase II) 0.2 ppm ozone + 150 micrograms/m3 nitric 211u001eacid vapor. In both phases, the exposures were separated by equal to or greater 211u001ethan 4 weeks. Following each exposure, subjects underwent inhalation challenges 211u001ewith dust mite (D. Farinae) allergen. A 6 h post-allergen exposure, brochoscopy 211u001ewith bronchoalveolar lavage (BAL) and endobronchial biopsy was performed. There 211u001ewas a trend toward increased sensitivity to inhaled allergen after ozone exposure 211u001ecompared to air on an individual level, but it was not significant for the whole 211u001egroup (p=0.42). A near-significant increase in BAL neutroophils after ozone 211u001eexposure (p=0.06) was not accompanied by an increase in inflammatory markers. The 211u001eonly significant change in Phase II was an increase in eosinophils (p=0.02) in 211u001eBAL after the ozone + nitric acid exposure. The results do not confirm the 211u001ehypothesis that ozone or ozone + nitric acid exposure. The results do not confirm 211u001ethe hypothesis that ozone or ozone + nitric acid vapor exposure enhances the 211u001eresponse to inhaled allergen in allergic asthmatics.