title: Repeat protocol renal biopsy in ANCA-associated renal vasculitis.
abstract: BACKGROUND
  Histopathological lesions in renal biopsy (RB) at presentation of ANCA-associated vasculitis (AAV) have been described in depth but repeat protocolized renal biopsies are seldomly performed in AAV. In this study, we present a group of AAV patients with repeat protocolized biopsies, and we evaluate their clinical significance.
  
  
  METHODS
  A total of 17 consecutive patients diagnosed between 1991 and 1995 with AAV and renal involvement confirmed by biopsy at presentation in a single center underwent a protocol planned rebiopsy in remission after a median of 13 months (range 11-28) from diagnosis. Biopsies were assessed by two independent pathologists, blinded to patient data. Clinical data were collected retrospectively.
  
  
  RESULTS
  Patients were followed-up for a median of 189 months from diagnosis. Renal relapse was observed in eight patients (47.1%), seven patients died, three patients reached end-stage renal failure. There was a significant decrease in the percentage of acute lesions (cellular crescents, fibrinoid necrosis, P < 0.001) and a significant increase in chronic lesions (glomerulosclerosis, interstitial fibrosis, P ≤ 0.01) in the repeat RB compared with the first RB. This resulted in a class change over the biopsies within most patients. The percentage of normal glomeruli in the first biopsy positively correlated with estimated GFR at the end of follow-up (rs = 0.509, P = 0.05).
  
  
  CONCLUSIONS
  This is the first study on protocolized repeat biopsies in AAV, giving insight into disease activity under immunosuppressive treatment. Apparently, many AAV patients have grumbling disease with ongoing activity, eventually leading to an increased amount of chronic lesions.
authors.affiliation: Department of Nephrology, General University Hospital and First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
authors.forename: Zdenka
authors.initials: Z
authors.lastname: Hruskova
authors.affiliation: Department of Pathology, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
authors.forename: Eva
authors.initials: E
authors.lastname: Honsova
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Annelies E
authors.initials: AE
authors.lastname: Berden
authors.affiliation: 2nd Department of Internal Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
authors.forename: Ivan
authors.initials: I
authors.lastname: Rychlik
authors.affiliation: Statistical Unit, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
authors.forename: Vera
authors.initials: V
authors.lastname: Lanska
authors.affiliation: 1st Department of Internal Medicine, Third Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Zabka
authors.affiliation: Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Ingeborg M
authors.initials: IM
authors.lastname: Bajema
authors.affiliation: Department of Nephrology, General University Hospital and First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Tesar
mesh_terms: D000328:Adult; D000368:Aged; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000473:pathology*; D001706:Biopsy / Q000379:methods; D002985:Clinical Protocols; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007668:Kidney / Q000473:pathology*; D007674:Kidney Diseases / Q000473:pathology*; D007678:Kidney Glomerulus / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D007166:Immunosuppressive Agents
keywords: ANCA; outcome; rebiopsy; renal biopsy; vasculitis