1. Department of Internal Medicine, Rheumatology and Immunology, Medius Kliniken, University of Tübingen, Kirchheim unter Teck, Germany
2. Rheumatology Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
3. Department of Nephrology, Hypertensiology and Rheumatology, University Hospital Mannheim, University of Heidelberg, Mannheim, Germany