[1] Hosp Clin Barcelona, Unitat Malalties Autoimmunes Sistemiques, Inst Clin Infecc & Immunol, Inst Invest Biomed August Pi & Sunyer, E-08036 Barcelona, Catalonia, Spain
[2] Univ Cape Town, Sch Med, Rheumat Dis Unit, Dept Med, ZA-7925 Cape Town, South Africa
[3] Hop La Pitie Salpetriere, Dept Internal Med, Paris, France
[4] Chaim Sheba Med Ctr, Res Ctr Autoimmune Dis, IL-52621 Tel Hashomer, Israel
[5] Johns Hopkins Univ Hosp, Div Rheumatol, Baltimore, MD 21287 USA
[6] Tan Tock Seng Hosp, Singapore, Singapore
[7] Barbara Ann Karmanos Canc Inst, Div Hematol Oncol, Detroit, MI USA
[8] Inst Rheumatol, Dept Connect Tissue Dis, Warsaw, Poland
[9] Englewood Hosp & Med Ctr, Dept Med, Englewood, NJ USA
[10] Benemerita Univ Autonoma Puebla, Dept Reumatol, Puebla, Mexico
[11] Univ Connecticut, Ctr Hlth, Div Rheumatol, Farmington, CT USA
[12] Hosp San Antonio, Dept Internal Med, Oporto, Portugal