aDepartment of Respiratory Diseases and Lung Transplantation Unit, University Hospital Gasthuisberg

bCHROMETA Department, Breathe Lab, KU Leuven, Leuven

cDepartment of Thoracic and Vascular Surgery & Pneumology UZA, University Hospital Antwerp, Edegem, Belgium

Correspondence to Geert M. Verleden, Department of Respiratory Diseases and Lung Transplantation Unit, University Hospital Gasthuis-berg, 49, Herestraat, B-3000 Leuven, Belgium. Tel: +32 16 346802; fax: +32 16 346803; e-mail: [email protected]