1 Division of Respiratory Diseases, IRCCS Policlinico San Matteo Foundation and Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy. Electronic address: corsico@unipv.it.
2 Department of Internal Medicine (Di.M.I.), University of Genoa, Genoa, Italy.
3 Department of Medical Sciences, University of Ferrara, Ferrara, Italy.
4 Department of Biomedical and Clinical Sciences (DIBIC), University of Milan, Milan, Italy.
5 Respiratory Unit, Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy.
6 Boehringer-Ingelheim, Milan, Italy.
7 Department of Health Sciences, University of Milan, Milan, Italy.