title: Evaluation of the FIDIS vasculitis multiplex immunoassay for diagnosis and follow-up of ANCA-associated vasculitis and Goodpasture's disease.
abstract: We have evaluated a new-multiplex immunoassay (FIDIS Vasculitis) for simultaneous detection and quantification of anti-MPO, -PR3, and -glomerular basement membrane (GBM) antibodies in diagnosis and follow-up of ANCA-associated vasculitides (AAV) and Goodpasture's disease. ANCA were determined in sera of (a) 87 consecutive patients with biopsy-proven pauci-immune NCGN and 72 controls; (b) 9 patients with Goodpasture's disease; and (c) 60 WG patients and 60 controls, previously used in a multicenter comparison of direct and capture ELISA for PR3-ANCA. Finally, for prediction of relapses, PR3-ANCA was measured in samples preceding relapse in 23 PR3-AAV patients and in 23 matched PR3-AAV patients without relapse. The relative sensitivity of the FIDIS Vasculitis assay was 97.4% for MPO-ANCA and 92.3% for PR3-ANCA; specificity was 100% and 97.2%, respectively. Evaluation of the anti-GBM antibody detection revealed a sensitivity of 100% and a specificity of 99.6%. The sensitivity for WG of the PR3-ANCA detection (71.6%) approached the performance of capture ELISA (74%), although at the cost of specificity (96.7% versus 100%). For prediction of relapses a rise of 50% in ANCA level by FIDIS Vasculitis appeared optimal (ROC curve) for prediction of relapses. However, as compared to capture ELISA, both positive (63% versus 76%) and negative (68% versus 72%) predictive values were reduced. In conclusion, simultaneous detection of anti-MPO, -PR3, and -GBM antibodies in the multiplex FIDIS Vasculitis assay has excellent performance in terms of diagnosis of patients with AAV or Goodpasture's disease. However, detection of rises in PR3-ANCA for prediction of relapses gives less optimal results when compared to capture ELISA.
authors.affiliation: Department of Clinical and Experimental Immunology, University Hospital Maastricht, the Netherlands. jdam@limm.azm.nl
authors.forename: J
authors.initials: J
authors.lastname: Damoiseaux
authors.forename: M
authors.initials: M
authors.lastname: Vaessen
authors.forename: Y
authors.initials: Y
authors.lastname: Knapen
authors.forename: E
authors.initials: E
authors.lastname: Csernok
authors.forename: C A
authors.initials: CA
authors.lastname: Stegeman
authors.forename: P
authors.initials: P
authors.lastname: Van Paassen
authors.forename: J W Cohen
authors.initials: JW
authors.lastname: Tervaert
mesh_terms: D019867:Anti-Glomerular Basement Membrane Disease / Q000097:blood* / Q000175:diagnosis* / Q000276:immunology; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood* / Q000276:immunology*; D001706:Biopsy; D005500:Follow-Up Studies; D014890:Granulomatosis with Polyangiitis / Q000097:blood / Q000175:diagnosis / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007668:Kidney / Q000601:surgery; D012008:Recurrence; D014657:Vasculitis / Q000097:blood* / Q000175:diagnosis* / Q000276:immunology