1. Department of Clinical Science & Community Health, University of Milano, 20122 Milan, Italy
2. Division of Rheumatology, Istituto Gaetano Pini, 20122 Milan, Italy
3. Medical Statistics and Biometry, 20122 Milan, Italy
4. Laboratory of Experimental Neurosurgery and Cell Therapy, Neurosurgery Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico Milano, 20122 Milan, Italy
5. Rheumatology Unit, Ospedale Moriggia-Pelascini, 22015 Gravedona, Italy