1 Respiratory Unit, S. Andrea Hospital, 13100 Vercelli, Italy.
2 Department of Traslational Medicine, University of Eastern Piedmont, 28100 Novara, Italy; Center for Translational Research on Autoimmune and Allergic Diseases, University of Piemonte Orientale, 28100 Novara, Italy.
3 Respiratory Unit, S. Andrea Hospital, 13100 Vercelli, Italy; Department of Traslational Medicine, University of Eastern Piedmont, 28100 Novara, Italy. Electronic address: mario.malerba@uniupo.it.