1. German Rheumatism Research Centre Berlin and Charité University Hospital Berlin; Berlin Germany
2. German Rheumatism Research Centre Berlin; Berlin Germany
3. St. Josef-Stift Sendenhorst Hospital; Sendenhorst Germany
4. Charité University Hospital Berlin; Berlin Germany
5. HELIOS Klinikum Krefeld; Krefeld Germany
6. University Medical Center Freiburg; Freiburg Germany
7. Hannover Medical School; Hannover Germany
8. Olgahospital, Clinical Center Stuttgart; Stuttgart Germany
9. Asklepios Clinic Sankt Augustin; St. Augustin Germany