[1] Catholic Univ Louvain, Clin Univ St Luc, Dept Rheumatol, Ave Hippocrate 10, B-1200 Brussels, Belgium
[2] Hosp Santo Antonio, Dept Internal Med, Porto, Portugal
[3] St Thomas Hosp, Louise Coote Lupus Unit, London, England
[4] Osped San Camillo, Dept Rheumatol, Rome, Italy
[5] Hosp Reg SAS Malaga, Dept Internal Med, Malaga, Spain
[6] Univ Politecn Marche, Med Clin, Dipartimento Sci Med & Chirurig, Ancona, Italy
[7] Univ Libre Bruxelles, Hop Erasme, Dept Nephrol, Brussels, Belgium
[8] Katholieke Univ Leuven, Gasthuisberg Acad Ziekenhuis, Gen Internal Med Dept, Leuven, Belgium
[9] Univ Cagliari, Dept Rheumatol, Cagliari, Italy
[10] Univ Marmara, Univ Marmara Hosp, Dept Rheumatol, Istanbul, Turkey
[11] Univ Siena, Dept Rheumatol, I-53100 Siena, Italy
[12] Istanbul Univ, Dept Rheumatol, Istanbul, Turkey
[13] Tel Aviv Univ, Chaim Sheba Med Ctr, Tel Hashomer, Israel
[14] Lainz Hosp, Dept Rheumatol, Vienna, Austria
[15] Mil Med Acad, Rheumatol & Clin Immunol Dept, Belgrade 11002, Serbia
[16] Univ Belgrade, Inst Rheumatol, Belgrade, Serbia
[17] Osped San Carlo Borromeo Milano, Clin Immunol & Renal Unit, Milan, Italy
[18] Univ Brescia, Osped Civile, Clin Immunol & Allergol Dept, Brescia, Italy
[19] Hosp Clin Barcelona, Inst Clin Med & Dermatol, Dept Autoimmune Dis, Barcelona, Catalonia, Spain
[20] Catholic Univ Louvain, Clin Univ St Luc, Dept Pathol, B-1200 Brussels, Belgium