Department of Biomedical and Clinical Sciences Luigi Sacco, Luigi Sacco Hospital, University of Milan, Via G.B. Grassi N° 74, 20157 Milan, Italy. Department of Medicine, Surgery and Pharmacy, University of Sassari, Viale San Pietro N° 8, 07100 Sassari, Italy. Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza, 28, 20122 Milan, Italy. Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA. Transfusion Center, Azienda Ospedaliero Universitaria, Piazza Università, N° 21, 07100 Sassari, Italy. Fondazione Mattarelli Largo della Crocetta, 2, 20122 Milan, Italy.