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.

Revised 2017 international consensus on testing of ANCAs in granulomatosis with polyangiitis and microscopic polyangiitis

“…However, innovations in ANCA detection have not only been limited to IIF and ELISAs; alternative solid-phase assays are also now being marketed, including dot and line immunoassays 53 , fluorescent-enzyme immunoassays (FEIA) 54,55 , addressable-laser-bead immunoassays (ALBIA) 56,57,58,59 and chemiluminescent immunoassays (CLIA) 60,61 . Many of these assays are reliable methods for ANCA detection, and such advances have challenged the role of IIF in ANCA testing and in the testing algorithm recommended by the 1999 international consensus 6 .…”

ANCA Diagnostics in Clinical Practice: New Developments

“…During the last decade, multiple variants of the direct ELISA have become available. These assays may differ in terms of the carrier, for instance a membrane in dotblot assays (Rutgers et al, 2004) and line-immuno-assays (LIA) or beads in multiplex flow cytometry (Nifli et al, 2006;Damoiseaux et al, 2007;Kaul et al, 2009), or by replacement of the enzyme by a fluorochrome, like in fluorescent-enzyme immuno-assays (FEIA) as well as the Luminex-based technology (Nifli et al, 2006;Damoiseaux et al, 2007;Kaul et al, 2009). More recently, also assays based on chemiluminesence technology have become available.…”

Diagnostik der Glomerulonephritiden

“…Bei einer Sensitivität der ELISA-Kits oder Dot-Blots von 60-100% [6,19,23] schließt ein negativer Befund eine Anti-GBM-Nephritis nicht aus. Bei bis zu 33% der Patienten mit Anti-GBM-Nephritis lassen sich auch ANCA, insbesondere mit der Spezifität gegen Myeloperoxidase (MPO), nachweisen.…”