title: Prediction of relapses in Wegener's granulomatosis by measurement of antineutrophil cytoplasmic antibody levels: a prospective study.
abstract: OBJECTIVE
  Prediction of relapses in Wegener's granulomatosis (WG) by measuring levels of antineutrophil cytoplasmic antibodies (ANCA) directed against proteinase 3 (PR3) or myeloperoxidase (MPO) remains a controversial issue. To assess the value of serial quantification of ANCA by indirect immunofluorescence (IIF) and antigen-specific enzyme-linked immunosorbent assay (ELISA) for monitoring disease activity in patients with WG, a prospective observational study was conducted in patients with WG attending an outpatient clinic in the Netherlands.
  
  
  METHODS
  One hundred patients with WG (85 with PR3-ANCA, 15 with MPO-ANCA) were studied prospectively from 1996 to 1998. Serum samples were obtained and analyzed every 2 months for ANCA levels. Disease activity was prospectively assessed without knowledge of the ANCA levels.
  
  
  RESULTS
  Relapses occurred in 37 of 100 patients (37%). Thirty-four (92%) of the 37 patients showed a rise in the level of ANCA preceding their relapse, as detected by ELISA or IIF. The predictive value of an increase in ANCA titers for relapse was 57% (17 of 30) for cytoplasmic/classic ANCA (cANCA; by IIF), 71% (27 of 38) for PR3-ANCA (by ELISA), and 100% (3 of 3) for MPO-ANCA (by ELISA). The predictive value of a rise in ANCA as measured by ELISA or IIF did not substantially improve following concomitant measurement of the IgG3 subclass of PR3-ANCA. Forty-three percent of patients who showed a rise in cANCA (by IIF) and 29% with a rise in PR3-ANCA (by ELISA) did not subsequently experience a relapse.
  
  
  CONCLUSIONS
  Serial measurement of ANCA levels is valuable for the early prediction of relapses in patients with WG.
authors.affiliation: University Hospital Groningen, The Netherlands.
authors.forename: M M
authors.initials: MM
authors.lastname: Boomsma
authors.forename: C A
authors.initials: CA
authors.lastname: Stegeman
authors.forename: M J
authors.initials: MJ
authors.lastname: van der Leij
authors.forename: W
authors.initials: W
authors.lastname: Oost
authors.forename: J
authors.initials: J
authors.lastname: Hermans
authors.forename: C G
authors.initials: CG
authors.lastname: Kallenberg
authors.forename: P C
authors.initials: PC
authors.lastname: Limburg
authors.forename: J W
authors.initials: JW
authors.lastname: Tervaert
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood* / Q000276:immunology; D000918:Antibody Specificity; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D014890:Granulomatosis with Polyangiitis / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009195:Peroxidase / Q000276:immunology; D012372:ROC Curve; D012008:Recurrence
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D009195:Peroxidase