Evaluation of a new fluorescent-enzyme immuno-assay for diagnosis and follow-up of ANCA-associated vasculitis

J Clin Immunol. 2005 May;25(3):202-8. doi: 10.1007/s10875-005-3863-2.


In this study we have evaluated a new, fully automated fluorescent-enzyme immuno-assay (FEIA) for detection and quantification of anti-PR3 and anti-MPO ANCA in diagnosis and follow-up of ANCA-associated small vessel vasculitis (AAV). PR3- and MPO-ANCA were determined by FEIA technology in (1) sera of 87 consecutive patients with biopsy-proven, pauci-immune necrotizing crescentic glomerulonephritis (NCGN) and 72 controls; (2) 120 sera (60 patients with Wegener's granulomatosis and 60 controls) that were previously used in a multicentre comparison of direct and capture ELISAs for PR3-ANCA; (3) in samples preceding relapse in 23 PR3-AAV patients with and 23 matched PR3-AAV patients without relapse for prediction of relapses. PR3- and/or MPO-ANCA detection in pauci-immune NCGN by FEIA revealed an overall sensitivity of 82.8%. The FEIA specificity was 96% and 100% for PR3- and MPO-ANCA, respectively. The overall sensitivity of MPO- and PR3-ANCA could be increased to 88.5% by lowering the cut-off values without affecting the specificity (ROC-curve analysis), which is similar to a multistep ANCA procedure that combines indirect immunofluorescence with direct and capture ELISAs. The sensitivity for Wegener's granulomatosis (WG) of the PR3-ANCA FEIA (60%) was more comparable to direct ELISAs (64%) than to capture ELISAs (74%). A rise of 100% in ANCA level as measured by FEIA appeared optimal (ROC-curve) for prediction of relapses and such a rise was observed in 26 patients. In 18 of these 26 patients the rise was followed by a relapse (PPV 69%), whereas in 15 of the 20 patients without a rise no relapse was observed (NPV 75%). In conclusion, detection of PR3- and MPO-ANCA by FEIA has excellent performance in terms of diagnosis of AAV patients. Furthermore, detection of rises in PR3-ANCA by FEIA for prediction of relapses gives results comparable to other techniques.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antibodies, Antineutrophil Cytoplasmic*
  • Autoantibodies / blood*
  • Case-Control Studies
  • Enzyme-Linked Immunosorbent Assay / methods
  • Enzyme-Linked Immunosorbent Assay / standards*
  • Female
  • Glomerulonephritis
  • Granulomatosis with Polyangiitis
  • Humans
  • Male
  • Middle Aged
  • Myeloblastin
  • Peroxidase / immunology
  • Predictive Value of Tests
  • Recurrence
  • Sensitivity and Specificity
  • Serine Endopeptidases / immunology
  • Vasculitis / diagnosis*
  • Vasculitis / immunology


  • Antibodies, Antineutrophil Cytoplasmic
  • Autoantibodies
  • Peroxidase
  • Serine Endopeptidases
  • Myeloblastin