Fc Proteoforms of ACPA IgG Discriminate Autoimmune Responses in Plasma and Synovial Fluid of Rheumatoid Arthritis Patients and Associate with Disease Activity

Abstract Autoantibodies and their post‐translational modifications (PTMs) are insightful markers of autoimmune diseases providing diagnostic and prognostic clues, thereby informing clinical decisions. However, current autoantibody analyses focus mostly on IgG1 glycosylation representing only a subpo...

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Main Authors: Constantin Blöchl, Eva Maria Stork, Hans Ulrich Scherer, Rene E. M. Toes, Manfred Wuhrer, Elena Domínguez‐Vega
Format: Article
Language:English
Published: Wiley 2025-04-01
Series:Advanced Science
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Online Access:https://doi.org/10.1002/advs.202408769
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author Constantin Blöchl
Eva Maria Stork
Hans Ulrich Scherer
Rene E. M. Toes
Manfred Wuhrer
Elena Domínguez‐Vega
author_facet Constantin Blöchl
Eva Maria Stork
Hans Ulrich Scherer
Rene E. M. Toes
Manfred Wuhrer
Elena Domínguez‐Vega
author_sort Constantin Blöchl
collection DOAJ
description Abstract Autoantibodies and their post‐translational modifications (PTMs) are insightful markers of autoimmune diseases providing diagnostic and prognostic clues, thereby informing clinical decisions. However, current autoantibody analyses focus mostly on IgG1 glycosylation representing only a subpopulation of the actual IgG proteome. Here, by taking rheumatoid arthritis (RA) as prototypic autoimmune disease, we sought to circumvent these shortcomings and illuminate the importance of (auto)antibody proteoforms employing a novel comprehensive mass spectrometry (MS)‐based analytical workflow. Profiling of anti‐citrullinated protein antibodies (ACPA) IgG and total IgG in paired samples of plasma and synovial fluid revealed a clear distinction of autoantibodies from total IgG and between biofluids. This discrimination relied on comprehensive subclass‐specific PTM profiles including previously neglected features such as IgG3 CH3 domain glycosylation, allotype ratios, and non‐glycosylated IgG. Intriguingly, specific proteoforms were found to correlate with markers of inflammation and disease accentuating the need of such approaches in clinical investigations and calling for further mechanistic studies to comprehend the role of autoantibody proteoforms in defining autoimmune responses.
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spelling doaj-art-c65eda0a83ce4c788617a2bb06c297322025-08-20T03:18:05ZengWileyAdvanced Science2198-38442025-04-011215n/an/a10.1002/advs.202408769Fc Proteoforms of ACPA IgG Discriminate Autoimmune Responses in Plasma and Synovial Fluid of Rheumatoid Arthritis Patients and Associate with Disease ActivityConstantin Blöchl0Eva Maria Stork1Hans Ulrich Scherer2Rene E. M. Toes3Manfred Wuhrer4Elena Domínguez‐Vega5Center for Proteomics and Metabolomics Leiden University Medical Center Albinusdreef 2 Leiden 2333 ZA The NetherlandsDepartment of Rheumatology Leiden University Medical Center Albinusdreef 2 Leiden 2333 ZA The NetherlandsDepartment of Rheumatology Leiden University Medical Center Albinusdreef 2 Leiden 2333 ZA The NetherlandsDepartment of Rheumatology Leiden University Medical Center Albinusdreef 2 Leiden 2333 ZA The NetherlandsCenter for Proteomics and Metabolomics Leiden University Medical Center Albinusdreef 2 Leiden 2333 ZA The NetherlandsCenter for Proteomics and Metabolomics Leiden University Medical Center Albinusdreef 2 Leiden 2333 ZA The NetherlandsAbstract Autoantibodies and their post‐translational modifications (PTMs) are insightful markers of autoimmune diseases providing diagnostic and prognostic clues, thereby informing clinical decisions. However, current autoantibody analyses focus mostly on IgG1 glycosylation representing only a subpopulation of the actual IgG proteome. Here, by taking rheumatoid arthritis (RA) as prototypic autoimmune disease, we sought to circumvent these shortcomings and illuminate the importance of (auto)antibody proteoforms employing a novel comprehensive mass spectrometry (MS)‐based analytical workflow. Profiling of anti‐citrullinated protein antibodies (ACPA) IgG and total IgG in paired samples of plasma and synovial fluid revealed a clear distinction of autoantibodies from total IgG and between biofluids. This discrimination relied on comprehensive subclass‐specific PTM profiles including previously neglected features such as IgG3 CH3 domain glycosylation, allotype ratios, and non‐glycosylated IgG. Intriguingly, specific proteoforms were found to correlate with markers of inflammation and disease accentuating the need of such approaches in clinical investigations and calling for further mechanistic studies to comprehend the role of autoantibody proteoforms in defining autoimmune responses.https://doi.org/10.1002/advs.202408769autoantibodiesautoimmunityHPLC‐MSIgG allotypes and subclassespolyclonal IgG
spellingShingle Constantin Blöchl
Eva Maria Stork
Hans Ulrich Scherer
Rene E. M. Toes
Manfred Wuhrer
Elena Domínguez‐Vega
Fc Proteoforms of ACPA IgG Discriminate Autoimmune Responses in Plasma and Synovial Fluid of Rheumatoid Arthritis Patients and Associate with Disease Activity
Advanced Science
autoantibodies
autoimmunity
HPLC‐MS
IgG allotypes and subclasses
polyclonal IgG
title Fc Proteoforms of ACPA IgG Discriminate Autoimmune Responses in Plasma and Synovial Fluid of Rheumatoid Arthritis Patients and Associate with Disease Activity
title_full Fc Proteoforms of ACPA IgG Discriminate Autoimmune Responses in Plasma and Synovial Fluid of Rheumatoid Arthritis Patients and Associate with Disease Activity
title_fullStr Fc Proteoforms of ACPA IgG Discriminate Autoimmune Responses in Plasma and Synovial Fluid of Rheumatoid Arthritis Patients and Associate with Disease Activity
title_full_unstemmed Fc Proteoforms of ACPA IgG Discriminate Autoimmune Responses in Plasma and Synovial Fluid of Rheumatoid Arthritis Patients and Associate with Disease Activity
title_short Fc Proteoforms of ACPA IgG Discriminate Autoimmune Responses in Plasma and Synovial Fluid of Rheumatoid Arthritis Patients and Associate with Disease Activity
title_sort fc proteoforms of acpa igg discriminate autoimmune responses in plasma and synovial fluid of rheumatoid arthritis patients and associate with disease activity
topic autoantibodies
autoimmunity
HPLC‐MS
IgG allotypes and subclasses
polyclonal IgG
url https://doi.org/10.1002/advs.202408769
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