INFLAMMATORY EFFECTS OF OZONE IN THE UPPER AIRWAYS OF SUBJECTS WITH ASTHMA

The objective of this study was to determine whether exposure to ozone causes inflammatory or functional changes in the upper or lower airwa ys of asthmatic and nonasthmatic individuals. Ten asthmatic and eight nonasthmatic subjects were exposed to clean air, 120 ppb ozone, or 240 ppb ozone for 90 min during intermittent moderate exercise using a he ad dome exposure system. Pulmonary function tests, posterior rhinomano metry, and nasal lavage were performed before and after exposure. Leuk ocyte counts and chemotactic factors leukotriene B-4 (LTB(4)), platele t-activating factor (PAF), and interleukin-8 (IL-8) were analyzed from nasal lavage fluid. In subjects with asthma, a significant increase ( p < 0.05) in the number of white blood cells in lavage fluid was detec ted both immediately and 24 h after exposure to 240 ppb ozone, as was a significant increase in epithelial cells immediately af ter exposure (p < 0.05). No significant cellular changes were seen in nonasthmatic subjects. A significant correlation was observed between IL-8 and whi te blood cell counts after exposure to 240 ppb ozone (r = 0.76) in ast hmatic subjects. No significant changes in pulmonary or nasal function or biochemical mediators were found in either the asthmatic or nonast hmatic subjects. These data indicate that asthmatic individuals are mo re sensitive to the acute inflammatory effects of ozone than nonasthma tic individuals.