1. Department of Respiratory Medicine, Royal Brompton & Harefield Hospital Foundation Trust, Harefield Hospital, Harefield, UK
2. Honorary Senior Clinical Lecturer, Respiratory Medicine, Imperial College, London,
UK
3. Department of Clinical and Experimental Medicine, University of Catania, Catania (CT),
Italy
4. Department of Biomedical and Biotechnological Sciences, University of Catania, Catania (CT), Italy