1. Pediatric Rheumatology & Immunology, Klinik und Poliklinik für Kinder- und Jugendmedizin, Universitätsklinikum Carl Gustav Carus, TU Dresden, Dresden, Germany
2. Department of Nephrology & Clinical Immunology, RWTH University Hospital, Aachen, Germany
3. Division of Rheumatology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA