1. AJG Swaak, Department of Rheumatology, Medisch Centrum Rijnmond Zuid,Groene Hilledijlk 315, 3075 EA Rotterdam, The Netherlands
2. Department of Auto-immune Diseases, Central Laboratory Blood Transfusion Service, Amsterdam, The Netherlands
3. Department of Internal Medicine III and Institute for Clinical Immunology, University Erlangen-Nurnberg, Erlangen, Germany
4. Rheumatology Unit, Istituto Ortopedico Gaetano Pini, Milano, Italy
5. Department of Rheumatology and Rehabilitation, University Hospital Zagreb,Zagreb, Croatia
6. Department of Rheumatology, Dr Peter Drzaj Hospital, Ljubljana, Slovenia
7. First Department of Internal Medicine, Dr A. Szent-Gyorgyi Medical University Centre, Szeged, Hungary
8. Blood Transfusion Institute, Dr A. Szent-Gyorgyi Medical University Centre, Szeged, Hungary
9. Department of Pathophysiology, School of Medicine, National University of Athens, Athens, Greece
10. Department of Connective Tissue Diseases, Institute of Rheumatology, Warsaw, Poland; 11Department of Internal Medicine, Medical University of Debrecen, Debrecen, Hungary
11. Department of Internal Medicine, Medical University of Debrecen, Debrecen, Hungary
12. Division of ClinicalImmunology and Rheumatology, Department of Medicine, University Hospital Center, Zagreb
13. Medical Clinic, Department of Rheumatology, Heinrich-Heine University, Dusseldorf, Germany
14. Universita degli Studi di Pisa, Dipartimenti di Medicina Interna, Italy
15. Department of Rheumatology, University of Vienna, Vienna, Austria