[1] Univ Firenze, Div Rheumatol, Dept Expt & Clin Med, Florence, Italy
[2] Ctr Rheumatol & Connect Tissue Dis, UCL Div Med, London, England
[3] Univ Firenze, Dept Neurosci Psychol Drug Res & Child Hlth, Florence, Italy
[4] Univ Calif Los Angeles, Dept Med, Div Rheumatol, Los Angeles, CA 90024 USA