aIRCCS Ospedale Galeazzi – Sant’Ambrogio, Rheumatology Department, Milan, Italy

bDepartment of Medicine, Division of Rheumatology, Autoimmunity, and Inflammation, University of California San Diego, La Jolla, California, USA

cDepartment of Biomedical and Clinical Sciences, University of Milan, Milan, Italy

Correspondence to Georgios Filippou, MD, PhD, Department of Biomedical and Clinical Sciences, IRCCS Ospedale Galeazzi – Sant’Ambrogio, Via Cristina Belgioioso, 173, Milan 20157, Italy. Tel: +390283502707; e-mail: [email protected]