Common clinical feature 1. Exertional dyspnea or nonproductive cough 2. Tachypnea and bibasilar end-inspiratory dry cracks 3. Bilateral diffuse infiltrates on chest radiographs 4. Presents as a rEStRICTIVE lung disease DLcol, PA2O2↑ 5. Varying degrees of fibrosis and inflammation, with or without evidence of granulomatous or secondary vascular changesCommon clinical feature 1. Exertional dyspnea or nonproductive cough 2. Tachypnea and bibasilar end-inspiratory dry cracks 3. Bilateral diffuse infiltrates on chest radiographs 4. Presents as a RESTRICTIVE lung disease, DLco↓, PA-aO2↑ 5. Varying degrees of fibrosis and inflammation, with or without evidence of granulomatous or secondary vascular changes