1 Rheumatology, Allergology and Clinical Immunology, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.
2 Rheumatology, Department of Medicine, University of Perugia, Italy.
3 Rheumatology, Allergology and Clinical Immunology, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy. roberto.perricone@uniroma2.it.