1 Dept of Respiratory Medicine, King's College Hospital, London, UK.
2 Dept of Respiratory Medicine and Allergy, King's College London, London, UK.
3 Dept of Clinical Science, University of Bergen, Bergen, Norway.
4 Faculty of Medicine, National Heart and Lung Institute, Imperial College, London, UK.
5 1st Dept of Tuberculosis and Respiratory Care, 1st Medical School and General University Hospital, Charles University in Prague, Prague, Czech Republic.
6 Dept of Clinical Immunology, Pulmonology and Rheumatology, University Hospital Centre "Sestre Milosrdnice", Zagreb, Croatia.