1 Department of Internal Medicine and Rheumatology, Teaching Hospital 'Policlinico-V. Emanuele', University of Catania, via Santa Sofia, Catania, Italy Artroreuma S.R.L. Corso S. Vito, Mascalucia, CT, Italy.
2 Department of Internal Medicine and Rheumatology, Teaching Hospital Policlinico-V. Emanuele', University of Catania, Via Santa Sofia 78, 95123 Catania, Italy.