Affiliation: | 1.Department of Nephrology, University Hospital Essen, University Duisburg-Essen, Hufelandstraße 55, 45136 Essen, Germany;2.Department of Rheumatology and Clinical Immunology, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands;3.Department of Rheumatology and Clinical Immunology, Kliniken Essen Süd, Propsteistraße 2, 45239 Essen, Germany |