Hydrogen peroxide in exhaled breath condensate (EBC) vs eosinophil count in induced sputum (IS) in parenchymal vs airways lung diseases

We compared exhaled breath condensate (EBC) and induced sputum (IS) for assessing inflammation in pulmonary diseases in patients with obstructive lung disease (n = 20), persistent cough >6 months (n = 20), interstitial lung disease (n = 25) and controls (n = 10). EBC was collected by suspending a Teflon perfluoroalkoxy tube installed in an ice-filled container and connected to a polypropylene test tube. IS was recovered after 20' inhalation of 3% saline with an ultrasonic nebulizer, and 300 cells were differentially counted in cytospin Giemsa-stained slides. H(2)0(2) was measured by a method based on oxidation of phenolsulfonphthalein (phenol red) mediated by horseradish peroxidases and H(2)0(2). Pulmonary function tests were performed by conventional methods. H(2)0(2) levels in EBC and % eosinophils in IS were significantly different between groups. A positive and significant correlation was found between % eosinophils in IS and the levels of H(2)0(2) in EBC for each group and for all patients combined.