[1] Univ Erlangen Nurnberg, Dept Internal Med 3, Erlangen, Germany
[2] Univ Erlangen Nurnberg, Inst Clin Immunol, Erlangen, Germany
[3] Leiden Univ, Med Ctr, Dept Rheumatol, Leiden, Netherlands
[4] Hosp Gen Univ Elda, Dept Rheumatol, Alicante, Spain
[5] Med Univ Vienna, Div Rheumatol, Dept Internal Med 3, Vienna, Austria
[6] Univ Coll London Hosp, Dept Rheumatol, London, England
[7] UCL, MRC Ctr Neuromuscular Dis, London, England
[8] Univ Hosp Zurich, Dept Rheumatol, Zurich, Switzerland
[9] Paris Descartes Univ, Cochin Hosp, AP HP,Rheumatol Dept,PRES Sorbonne Paris Cite, INSERM,Clin Epidemiol & Biostat U1153, Paris, France
[10] Sapienza Univ Roma, Rheumatol Unit, Rome, Italy
[11] Univ Utrecht, Med Ctr, Utrecht, Netherlands
[12] Karolinska Univ Hosp, Dept Med, Rheumatol Unit, Solna, Sweden
[13] Karolinska Inst, Stockholm, Sweden