1. Department of Pulmonology, University Hospital Zurich , Rämistrasse 100, Zurich 8091 , Switzerland
2. Department of Pulmonology, University of Zurich , Zurich , Switzerland
3. Clinic of Respiratory Medicine and Pulmonary Cell Research, University Hospital Basel , Basel , Switzerland
4. Department of Pulmonary Medicine and Department for BioMedical Research, Inselspital, Bern University Hospital, University of Bern , Bern , Switzerland
5. Department of Pulmonology, University Hospital Lausanne , Lausanne , Switzerland
6. Department of Pulmonology, University Hospital Geneva , Geneva , Switzerland
7. Department of Angiology, Ospedale La Carità , Locarno , Switzerland
8. Service of Pulmonology, Hospital Neuchâtelois , Neuchâtel , Switzerland
9. Lung Center, Cantonal Hospital St Gallen , St Gallen , Switzerland