[1] Osped Riuniti Bergamo, I-24100 Bergamo, Italy
[2] Meyer Childrens Hosp, Florence, Italy
[3] Univ Florence, Florence, Italy
[4] Univ Pavia, Div Rheumatol, I-27100 Pavia, Italy
[5] IRCCS Policlin San Matteo Fdn, Pavia, Italy
[6] NYU, Sch Med, New York, NY 10016 USA