Epitope analysis of anti-myeloperoxidase antibodies in patients with ANCA-associated vasculitis

Gou, Shaohua; Xu, Pengcheng; Chen, M.; Zhao, Ming‐Hui

doi:10.1016/j.lpm.2013.02.246

Cited by 7 publications

(13 citation statements)

References 24 publications

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“…This caveat holds true for patient sera, as well as for the reference antibody preparations. Antibodies differ in terms of their IgG subclass composition as well as the avidity, glycosylation and epitope specificity of the antibodies [65][66][67][68][69][70][71][72][73][74] . In particular, epitope specificity might affect standardization of different assay formats, as the accessibility of epitopes might differ between different assay formats.…”

Section: Harmonization and Standardization Of Anca Testingmentioning

confidence: 99%

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

et al. 2017

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| Anti-neutrophil cytoplasmic antibodies (ANCAs) are valuable laboratory markers used for the diagnosis of well-defined types of small-vessel vasculitis, including granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). According to the 1999 international consensus on ANCA testing, indirect immunofluorescence (IIF) should be used to screen for ANCAs, and samples containing ANCAs should then be tested by immunoassays for proteinase 3 (PR3)-ANCAs and myeloperoxidase (MPO)-ANCAs. The distinction between PR3-ANCAs and MPO-ANCAs has important clinical and pathogenic implications. As dependable immunoassays for PR3-ANCAs and MPO-ANCAs have become broadly available, there is increasing international agreement that high-quality immunoassays are the preferred screening method for the diagnosis of ANCA-associated vasculitis. The present Consensus Statement proposes that high-quality immunoassays can be used as the primary screening method for patients suspected of having the ANCA-associated vaculitides GPA and MPA without the categorical need for IIF, and presents and discusses evidence to support this recommendation.NATURE REVIEWS | RHEUMATOLOGY VOLUME 13 | NOVEMBER 2017 | 683 CONSENSUS STATEMENT © 2 0 1 7 M a c m i l l a n P u b l i s h e r s L i m i t e d , p a r t o f S p r i n g e r N a t u r e . A l l r i g h t s r e s e r v e d .Given the improvements in antigen-specific immuno assays, the international consensus on the testing of ANCAs in small-vessel vasculitis seems in need of updating [7][8][9][10] . In this manuscript, a revised 2017 international consensus is proposed by a group of international experts (from North and Central America, Australia, Europe and Asia) in the ANCA field. This Consensus Statement highlights the value of ANCA testing as a tool for diagnosis (but not follow-up) of GPA and MPA and gives a historical perspective of ANCAs in small-vessel vasculitis. This Consensus Statement does not, however, present evidence-based guidelines or a meta-analysis. MethodsThis Consensus Statement was prepared by a group of experts from four European laboratories (X.B., J.D., N.R., J.W.C.T. and E.C.) in person and by correspondence. The draft was circulated to each contributor and modified, and the resulting document was distributed by e-mail to 16 experts from four continents, selected based on their expertise and knowledge in clinical and/or laboratory aspects of AAV. This revised document resulted in a second round of discussions and revisions. The final document was returned to all contributors for ratification.The Consensus Statement is based on the results of a multicentre European Vasculitis Study Group (EUVAS) evaluation of the value of IIF versus antigen-specific immunoassays for ANCA detection 6,11,12 . This study, which showed a large variability between different IIF methods and a good diagnostic performance of PR3-ANCA and MPO-ANCA immunoassays 6 , indicated that the 1999 international consensus on ANCA testing for AAV needed revision. When the consensus was put toget...

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Section: Harmonization and Standardization Of Anca Testingmentioning

confidence: 99%

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

et al. 2017

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“…A panel of 13 sequential overlapping peptides was synthesized, covering amino acids (aa) 279-410 of MPO (14). Each peptide was 20 aa in length, with ten overlapping aa.…”

Section: Preparation Of Linear Peptidesmentioning

confidence: 99%

“…Twenty peptides unrelated to MPO or GBM were also synthesized as peptide controls. In addition, a linear fragment of the MPO C-terminus (H4; aa 622-745) was produced in Escherichia coli, as previously described (14).…”

Section: Preparation Of Linear Peptidesmentioning

confidence: 99%

“…We previously reported that MPO peptide recognition was restricted to the 1 H fragment in double-positive patients (14). Therefore, we synthesized 13 sequential linear peptides covering the entire length of MPO Table 1).…”

Section: Frequency Of Serum Autoantibodies Recognizing Linear Peptidementioning

confidence: 99%

“…These findings implicate diverse autoantibodies against different MPO epitopes in the pathogenesis of ANCA-associated vasculitis. We recently screened autoantibodies against six fragments of the MPO molecule, covering both the light and the heavy chains, in plasma from patients with MPO-ANCAassociated vasculitis; a linear fragment of the N-terminal portion of the MPO heavy chain, 1 H 279-409 , was recognized in the majority of samples (61.5%, eight out of 13) from double-positive patients (14).…”

Section: Introductionmentioning

confidence: 99%

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Autoantibodies against Linear Epitopes of Myeloperoxidase in Anti–Glomerular Basement Membrane Disease

Cui

Wang

et al. 2016

Clinical Journal of the American Society of Nephrology

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Background and objectives Approximately 20%-30% of patients with anti-glomerular basement membrane disease present coexisting anti-myeloperoxidase (MPO) autoantibodies. We previously showed the recognition of a linear fragment of the MPO heavy chain N-terminus ( 1 H, MPO 279-409 ) in plasma from most double-positive patients. Herein, we investigated the frequency of autoantibodies against overlapping 1 H-derived linear peptides in plasma from patients with anti-glomerular basement membrane disease.Design, setting, participants, & measurements We synthesized 13 overlapping linear peptides ( 1 H-1 to 1 H-13) covering MPO . We retrospectively collected plasma samples from 67 patients with anti-glomerular basement membrane disease from 1996 to 2012, and we screened them for IgG autoantibodies by ELISA using intact human MPO and the overlapping peptides as antigens, and we further investigated the clinical significance. Autoantibody binding to the linear MPO structure was confirmed by Western blotting.Results We followed up the 67 patients until 2015, with a median follow-up time of 10.0 (2.3-36.0) months, and 56 ESRD events occurred among the 67 patients with follow-up data. Plasma from 23.9% (16) of the patients recognized intact human MPO, whereas 62.7% (42) plasma samples recognized MPO 279-409 linear peptides. Of the 13 linear peptides, 1 H-4 (44.8%, 30 patients) and 1 H-12 (40.3%, 27 patients) exhibited the highest recognition frequencies. Patients with autoantibodies against 1 H-11 or 1 H-12 (MPO 371-400 ) were older (46.1618.8 versus 34.1616.6 years; P,0.01), had higher serum creatinine upon diagnosis (median 7.8 mg/dl, interquartile range 4.9-12.6 mg/dl versus median 5.4 mg/dl, interquartile range 2.4-7.3 mg/dl; P=0.02), and had a higher probability of progressing to ESRD; however, multivariate Cox regression analysis showed that 1 H-11 or 12 reaction was not an independent risk factor for renal failure (hazard ratio, 1.2; 95% confidence interval, 0.8 to 2.8; P=0.19).Conclusions Autoantibodies against linear peptides of MPO can be detected in the majority of patients with antiglomerular basement membrane disease, and several are associated with disease severity. The potential common pathogenic mechanism between anti-glomerular basement membrane antibodies and anti-MPO autoantibodies in anti-glomerular basement membrane disease requires further investigation.

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Deglycosylation of myeloperoxidase uncovers its novel antigenicity

Wang

et al. 2017

Kidney International

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Myeloperoxidase (MPO) is a common target antigen of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and is recognized in one-third of patients with anti-glomerular basement membrane (GBM) disease. Our previous study identified over 60% of patients with anti-GBM disease recognizing linear peptides of MPO heavy chain. Here we tested whether aberrant glycosylation alters MPO antigenicity through exposure of neo-epitopes on MPO molecules. Atypical glycosylated MPO molecules, including all possible glycosylation types, were prepared by exoglycosidase and endoglycosidase treatments. Antibodies were detected from the sera of 40 patients with anti-GBM disease without the coexistence of MPO-ANCA. Circulating antibodies against aberrant glycosylated MPO existed in 21 of these patients. Non-glycan MPO and MPO with only N-acetylglucosamine had high frequencies of recognition (16 and 15 patients, respectively). Antibodies binding to aberrant glycosylated MPO could not be inhibited by intact MPO or GBM antigen. When applied to ethanol-fixed neutrophils from normal individuals, these antibodies yielded a typical cytoplasmic staining pattern (c-ANCA). Antigen specificity was detected in 90% of the antibodies using five peptides containing one of the five N-glycosylation sites each, mostly on N323, N355, and N391. The antibodies were restricted to IgG1 subclass, could activate complement, and induce neutrophil degranulation in vitro. Thus, aberrant glycosylated MPO exposed neo-epitopes and was recognized by half of the patients with anti-GBM disease. Their antibodies possessed pathogenic characteristics and may be associated with kidney injury.

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Epitope analysis of anti-myeloperoxidase antibodies in patients with ANCA-associated vasculitis

Cited by 7 publications

References 24 publications

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

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

Autoantibodies against Linear Epitopes of Myeloperoxidase in Anti–Glomerular Basement Membrane Disease

Deglycosylation of myeloperoxidase uncovers its novel antigenicity

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