Fluticasone propionate protects against ozone-induced airway inflammation and modified immune cell activation markers in healthy volunteers

BACKGROUND: Ozone exposure induces airway neutrophilia and modifies innate immune monocytic cell-surface phenotypes in healthy individuals. High-dose inhaled corticosteroids can reduce O-3-induced airway inflammation, but their effect on innate immune activation is unknown. OBJECTIVES: We used a human O-3 inhalation challenge model to examine the effectiveness of clinically relevant doses of inhaled corticosteroids on airway inflammation and markers of innate immune activation in healthy volunteers. METHODS: Seventeen O-3-responsive subjects [> 10% increase in the percentage of polymorphonuclear leukocytes (PMNs) in sputum, PMNs per milligram vs. baseline sputum] received placebo, or either a single therapeutic dose (0.5 mg) or a high dose (2 mg) of inhaled fluticasone proprionate (FP) 1 hr before a 3-hr O-3 challenge (0.25 ppm) on three separate occasions at least 2 weeks apart. Lung function, exhaled nitric oxide, sputum, and systemic biomarkers were assessed 1-5 hr after the O-3 challenge. To determine the effect of FP on cellular function, we assessed sputum cells from seven subjects by flow cytometry for cell-surface marker activation. RESULTS: FP had no effect on O-3-induced lung function decline. Compared with placebo, 0.5 mg and 2 mg FP reduced O-3-induced sputum neutrophilia by 18% and 35%, respectively. A similar effect was observed on the airway-specific serum biomarker Clara cell protein 16 (CCP16). Furthermore, FP pretreatment significantly reduced O-3-induced modification of CD11b, mCD14, CD64, CD16, HLA-DR, and CD86 on sputum monocytes in a dose-dependent manner. CONCLUSIONS: This study confirmed and extended data demonstrating the protective effect of FP against O-3-induced airway inflammation and immune cell activation.