[1] Univ Barcelona, Serv Malaties Autoimmunes, Hosp Clin,IDIBAPS, Dept Autoimmune Dis,Inst Clin Infecc & Immunol, Barcelona 08036, Catalonia, Spain
[2] St Thomas Hosp, Rayne Inst, Lupus Unit, London SE1 7EH, England
[3] Osped San Camillo De Lellis, Div Reumatol, Rome, Italy
[4] Hosp La Paz, Med Interna Serv, Madrid, Spain
[5] Ankara Univ, Sch Med, Dept Clin Immunol & Rheumatol, TR-06100 Ankara, Turkey
[6] Inst Rheumatol, Dept Connect Tissue Dis, Warsaw, Poland
[7] Hosp Reg Carlos Haya, Unidad Enfermedades Autoimmunes Sistem, Med Interna Serv, Malaga, Spain
[8] Hosp Reg Carlos Haya, Unidad Enfermedades Autoimmunes Sistem, Serv Nefrol, Malaga, Spain
[9] Hosp Clin Univ, Med Interna Serv, Malaga, Spain
[10] Hosp Clin Univ, Secc Reumatol, Malaga, Spain
[11] Univ Siena, Ist Reumatol, I-53100 Siena, Italy
[12] Haukeland Hosp, Dept Rheumatol, Bergen, Norway
[13] Univ Cagliari, Cattedra Reumatol, Cagliari, Italy
[14] Clin Univ St Luc, Serv Rheumatol, Catholic Univ Louvain, B-1200 Brussels, Belgium