[Permeability changes in bronchiolo-alveolar epithelium].

The pathophysiology in the bronchiolo-alveolar region in healthy smokers and patients with interstitial lung diseases was assessed in terms of changes in epithelial permeability. The pulmonary epithelial permeability was estimated by the rate constant (referred to as "kep") of inhaled 99mTc-DTPA (diethylene triamine penta acetate) clearance from the lungs. Healthy nonsmokers had a mean kep value of 0.82 +/- 0.26%/min, and their kep values were constant irrespective of age or sex. Of healthy smokers 53% showed increased permeability. Young smoking males, whose lung injury was supposed to be limited mainly to respiratory bronchioles, showed increased permeability. This increase was correlated with their cigarette consumption per day and was reversible after stopping smoking. The patients with interstitial lung diseases also showed increased permeability as compared with healthy non-smokers. We believe that the method is a sensitive test to detect inflammatory changes in the bronchiolo-alveolar epithelium.