[1] Univ West England, Ctr Hlth & Clin Res, Bristol, England
[2] Univ Autonoma Barcelona, Dept Nephrol, Barcelona, Spain
[3] Vasculitis Stichting, Maarssen, Netherlands
[4] CSL Vifor, Glattbrugg, Switzerland
[5] Univ Pavia, Dept Internal Med & Therapeut, Pavia, Italy
[6] Med Univ Innsbruck, Dept Internal Med Nephrol & Hypertens 4, Innsbruck, Austria
[7] Bristol Royal Infirm & Gen Hosp, Room 5-054,Rheumatol Res B502, Bristol BS2 8H, England