1. Department of Nephrology, Leiden University Medical Center , Leiden
2. Department of Rheumatology and Clinical Immunology, Amsterdam University Medical Centers , Amsterdam
3. Department of Nephrology, Spaarne Gasthuis , Haarlem
4. Department of Nephrology, Hagaziekenhuis , Den Haag
5. Department of Nephrology, Meander Medical Center , Amersfoort
6. Department of Nephrology, Groene Hart Hospital , Gouda
7. Department of Nephrology, Ziekenhuisgroep Twente , Almelo/Hengelo
8. Department of Rheumatology and Clinical Immunology, University Medical Center Groningen , Groningen
9. Department of Rheumatology and Clinical Immunology, University Medical Center Utrecht , Utrecht
10. Department of Rheumatology and Clinical Immunology, Ziekenhuisgroep Twente , Almelo/Hengelo
11. The Dutch Vasculitis Foundation , Silvolde
12. Department of Internal Medicine, St. Antonius Hospital , Nieuwegein, The Netherlands