Dataset Information

Epitope analysis of anti-myeloperoxidase antibodies in propylthiouracil-induced antineutrophil cytoplasmic antibody-associated vasculitis.

ABSTRACT:

Introduction

Increasing evidence has suggested that linear epitopes of antineutrophil cytoplasmic antibody (ANCA) directed to myeloperoxidase (MPO) might provide clues to the pathogenesis of propylthiouracil (PTU)-induced ANCA-associated vasculitis (AAV). This study mapped epitopes of MPO-ANCA in sera from patients with PTU-induced MPO-ANCA (with or without vasculitis) and primary AAV, aiming to analyze certain epitopes associated with the development of PTU-induced AAV.

Methods

Six recombinant linear fragments, covering the whole amino acid sequence of a single chain of MPO, were produced from Escherichia coli. Sera from 17 patients with PTU-induced AAV, 17 patients with PTU-induced MPO-ANCA but without clinical evidence of vasculitis, and 64 patients with primary AAV were collected at presentation. Of the 17 patients with PTU-induced AAV, 12 also had sera at remission. The epitope specificities were detected by enzyme-linked immunosorbent assay by using the recombinant fragments as solid-phase ligands.

Results

Compared with patients with PTU-induced MPO-ANCA but without clinical vasculitis, sera from PTU-induced AAV patients showed significantly higher reactivity against the H1 fragment of MPO (optical density values: 0.17 (0.10 to 0.35) versus 0.10 (0.04 to 0.21), P?=?0.038) and could recognize a significantly higher number of fragments (two (none to four) versus one (none to two), P?=?0.026). Compared with sera from primary AAV patients, sera from PTU-induced AAV patients had significantly higher reactivity to the P fragment and the H4 fragment (47.1% versus 14.1% P?ConclusionsLinear epitopes of MPO molecules might be associated closely with PTU-induced AAV. In particular, the P and H4 fragments may be important epitopes in PTU-induced AAV.

SUBMITTER: Wang C

PROVIDER: S-EPMC3979166 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

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Publications

Epitope analysis of anti-myeloperoxidase antibodies in propylthiouracil-induced antineutrophil cytoplasmic antibody-associated vasculitis.

Wang Chen C Gou Shen-ju SJ Xu Peng-cheng PC Zhao Ming-hui MH Chen Min M

Arthritis research & therapy 20130101 6

<h4>Introduction</h4>Increasing evidence has suggested that linear epitopes of antineutrophil cytoplasmic antibody (ANCA) directed to myeloperoxidase (MPO) might provide clues to the pathogenesis of propylthiouracil (PTU)-induced ANCA-associated vasculitis (AAV). This study mapped epitopes of MPO-ANCA in sera from patients with PTU-induced MPO-ANCA (with or without vasculitis) and primary AAV, aiming to analyze certain epitopes associated with the development of PTU-induced AAV.<h4>Methods</h4>S ...[more]

PMID: 24252385

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Project description:OBJECTIVE:There is accumulating evidence that complement activation is important in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) pathogenesis. This study was undertaken to investigate complement activation in AAV with myeloperoxidase (MPO) positivity and AAV with proteinase 3 (PR3) positivity after determining optimal methods for measuring activated complement factors in circulation. METHODS:Participants included 98 patients with AAV (45 MPO-ANCA positive, 53 PR3-ANCA positive) and 35 healthy controls. Plasma was obtained from blood collected using EDTA tubes, with or without 100 ?g/ml Futhan. Levels of Bb, C3a, C5a, soluble C5b-9 (sC5b-9), properdin, and C4d were measured by enzyme-linked immunosorbent assay. Group comparisons were made using Wilcoxon's 2-sample test. Paired data were analyzed using a matched pairs signed rank test. RESULTS:Compared to healthy controls, certain complement analyte levels were high in patients with active AAV with MPO positivity, including C3a (P < 0.0001), C5a (P = 0.0004), and sC5b-9 (P = 0.0007). During remission, levels of Bb (P = 0.001), C3a (P < 0.0001), and sC5b-9 (P = 0.003) were higher. Compared to healthy controls, C3a (P < 0.0001), C5a (P = 0.002), sC5b-9 (P = 0.0001), and C4d (P = 0.005) levels were higher in patients with active AAV with PR3 positivity; levels of C3a (P < 0.0001) and C4d (P = 0.007) were also higher duriing remission. There were no significant differences in any complement analyte for either ANCA serotype between patients with active disease and those with disease in remission. Among patients with paired samples, sC5-9 levels were significantly lower during disease remission compared to active disease. C5a was significantly lower among patients with disease in long-term remission who were not receiving therapy. For Bb, C5a, and sC5b-9, median levels and individual values were considerably higher in control and patient samples processed without Futhan compared to those processed with Futhan. CONCLUSION:Complement activation occurs in both MPO-positive AAV and PR3-positive AAV. The complement activation profile differs according to disease activity and possibly ANCA serotype. Futhan reduces in vitro complement activation and provides a more accurate measurement.

Project description:OBJECTIVE:To evaluate circulating cytokine profiles in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV), classified by antineutrophil cytoplasmic antibody (ANCA) specificity (proteinase 3 ANCA [PR3-ANCA] versus myeloperoxidase ANCA [MPO-ANCA]) or by clinical diagnosis (granulomatosis with polyangiitis [GPA] versus microscopic polyangiitis [MPA]). METHODS:A panel of 29 cytokines was tested in 186 patients with active AAV at inclusion into the Rituximab in AAV trial. Cytokine concentrations were compared between groups within each classification system. Multivariable analyses adjusted for age, sex, and renal insufficiency were performed, with each biomarker as a dependent variable and ANCA specificity and clinical diagnosis as explanatory variables of interest. RESULTS:Levels of 9 circulating cytokines (interleukin-6 [IL-6], granulocyte-macrophage colony-stimulating factor [GM-CSF], IL-15, IL-18, CXCL8/IL-8, CCL-17/thymus and activation-regulated chemokine [TARC], IL-18 binding protein [IL-18 BP], soluble IL-2 receptor ? [sIL-2R?], and nerve growth factor ? [NGF?]) were significantly higher in PR3-AAV than MPO-AAV, 4 cytokines (sIL6R, soluble tumor necrosis factor receptor type II [sTNFRII], neutrophil gelatinase-associated lipocalin [NGAL], and soluble intercellular adhesion molecule 1 [sICAM-1]) were higher in MPO-AAV than in PR3-AAV, 6 cytokines (IL-6, GM-CSF, IL-15, IL-18, sIL-2R?, and NGF?) were higher in GPA than in MPA, and 3 cytokines (osteopontin, sTNFRII, and NGAL) were higher in MPA than in GPA (all P < 0.05). For nearly all cytokines, the difference between PR3-AAV and MPO-AAV was larger than that between GPA and MPA. The multivariate analysis showed that 8 cytokines (IL-15, IL-8, IL-18 BP, NGF-?, sICAM-1, TARC, osteopontin, and kidney injury molecule 1 (P < 0.05) distinguished patients with AAV better (lower P values and larger effect sizes) when grouped by ANCA specificity than by clinical diagnosis. CONCLUSION:Distinct cytokine profiles were identified for PR3-AAV versus MPO-AAV and for GPA versus MPA. Differences in these circulating immune mediators are more strongly associated with ANCA specificity than with clinical diagnosis, suggesting that heterogeneity in the AAV subtypes extends beyond clinical phenotypes.

Dataset Information

Epitope analysis of anti-myeloperoxidase antibodies in propylthiouracil-induced antineutrophil cytoplasmic antibody-associated vasculitis.

Introduction

Methods

Results

Publications

Epitope analysis of anti-myeloperoxidase antibodies in propylthiouracil-induced antineutrophil cytoplasmic antibody-associated vasculitis.

Similar Datasets

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