2 Rheumatology Unit, Department of Specialistic Medicine, Azienda USL -IRCCS di Reggio Emilia.
3 Operative Unit of Pathologic Anatomy, Azienda USL -IRCCS di Reggio Emilia, Italy.
4 University of Modena and Reggio Emilia, Modena; Rheumatology Unit, Department of Specialistic Medicine, Azienda USL -IRCCS di Reggio Emilia. Electronic address: salvarani.carlo@ausl.re.it.