1 Department of Internal Medicine, University of Genova and IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy.
2 School and Operative Unit of Allergy and Clinical Immunology, Department of Clinical and Experimental Medicine, University of Messina, 98125 Messina, Italy.
3 Internal Medicine Department, San Paolo Hospital, 17100 Savona, Italy.