Abstract
We evaluated fibronectin levels in plasma and blood leukocyte counts after platelet-activating fac-tor-acether (PAF) inhalation to examine whether PAF may cause pulmonary vascular injury. PAF inhalation challenges were performed on 5 normal subjects and 5 atopic asthmatics. Fibronectin levels in plasma were significantly increased at 5 min (342.5 ± 36.9 ug/ml) after PAF challenge as compared with the baseline values of 277.1 ±33.0 ug/ml (p<0.024). Total white blood cell and neutrophil counts were significantly decreased 5 min after PAF inhalation (WBC from 5, 360 ±460 to 4, 260 ±380/mm3 p<0.028; neutrophils from 3, 113 ±441 to 2, 214 ± 344/mm3, p<0.043). Our study shows that plasma fibronectin levels transiently increase and that peripheral total WBC counts decrease after PAF inhalation. Elevated fibronectin levels may provide evidence of pulmonary vascular injury due to neutrophils which might be primed and recruited to pulmonary circulation by PAF.