[1] Univ Barcelona, Unitat Malalties Autoimmunes Sistem, Hosp Clin, Dept Med,Inst Invest Biomed August Pi I Sunyer, E-08036 Barcelona, Catalonia, Spain
[2] Univ Cape Town, Sch Med, Dept Med, Rheumat Dis Unit, ZA-7925 Cape Town, South Africa
[3] Hop La Pitie Salpetriere, Dept Internal Med, Paris, France
[4] Hop Tenon, Dept Nephrol, F-75970 Paris, France
[5] Hop Antoine Beclere, Dept Internal Med, Clamart, France
[6] Univ Calif Davis, Med Ctr, Dept Pathol, Sacramento, CA 95817 USA
[7] Int Inst Clin & Sci Res, Pittsburgh, PA USA
[8] Kings Mill Ctr Hlth Care SErv, Sutton, Surrey, England
[9] Univ Estado Rio De Janeiro, Hosp Pedro Ernesto, Dept Rheumatol, Rio De Janeiro, Brazil