The C3dg Fragment of Complement Is Superior to Conventional C3 as a Diagnostic Biomarker in Systemic Lupus Erythematosus
Introduction/objectivesIn 2012, hypocomplementemia was included in the classification criteria of systemic lupus erythematosus (SLE). The suggested measurement of C3 or C4 often reflect disease activity poorly. Our objective was to establish an assay measuring C3dg, which is generated following comp...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2018-03-01
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| Series: | Frontiers in Immunology |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fimmu.2018.00581/full |
| _version_ | 1819095746005172224 |
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| author | Anne Troldborg Anne Troldborg Lisbeth Jensen Bent Deleuran Bent Deleuran Kristian Stengaard-Pedersen Kristian Stengaard-Pedersen Steffen Thiel Jens Christian Jensenius |
| author_facet | Anne Troldborg Anne Troldborg Lisbeth Jensen Bent Deleuran Bent Deleuran Kristian Stengaard-Pedersen Kristian Stengaard-Pedersen Steffen Thiel Jens Christian Jensenius |
| author_sort | Anne Troldborg |
| collection | DOAJ |
| description | Introduction/objectivesIn 2012, hypocomplementemia was included in the classification criteria of systemic lupus erythematosus (SLE). The suggested measurement of C3 or C4 often reflect disease activity poorly. Our objective was to establish an assay measuring C3dg, which is generated following complement activation, and to evaluate the assay in a cross-sectional SLE cohort.MethodWe included SLE patients (n = 169) and controls (n = 170) and developed a modified C3dg assay where C3dg fragments were separated from the large plasma proteins by polyethylene glycol (PEG), and the supernatant containing the C3dg fragment was used for analysis in an antibody-based sandwich-type assay. Gel permeation chromatography and western blotting were used to establish the optimal conditions for PEG precipitation.Results16% PEG was optimal for separating C3dg from C3 and the larger protein fragments. The assay showed a high degree of stability when using EDTA plasma, and measurements correlated well with commercially available complement activation assays. SLE patients had higher concentrations in plasma of C3dg than controls (p < 0.05). ROC analysis showed that the C3dg activation fragment of C3 with an AUC of 0.96 (CI 0.94–0.98) was superior to C3 (AUC 0.52) in differentiating between patients and controls.ConclusionOur results present a modified assay for the measurement of C3dg. We demonstrate that C3dg was superior to conventional C3 measurements in discriminating SLE patients from controls. We suggest that C3dg should be considered as a complement activation measurement in the SLE classification criteria. |
| first_indexed | 2024-12-21T23:48:12Z |
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| issn | 1664-3224 |
| language | English |
| last_indexed | 2024-12-21T23:48:12Z |
| publishDate | 2018-03-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Immunology |
| spelling | doaj.art-d26dc7b3e02645069cadfeb59a00d2532022-12-21T18:46:00ZengFrontiers Media S.A.Frontiers in Immunology1664-32242018-03-01910.3389/fimmu.2018.00581339994The C3dg Fragment of Complement Is Superior to Conventional C3 as a Diagnostic Biomarker in Systemic Lupus ErythematosusAnne Troldborg0Anne Troldborg1Lisbeth Jensen2Bent Deleuran3Bent Deleuran4Kristian Stengaard-Pedersen5Kristian Stengaard-Pedersen6Steffen Thiel7Jens Christian Jensenius8Department of Rheumatology, Aarhus University Hospital, Aarhus, DenmarkInstitute of Clinical Medicine, Aarhus University, Aarhus, DenmarkDepartment of Biomedicine, Aarhus University, Aarhus, DenmarkDepartment of Rheumatology, Aarhus University Hospital, Aarhus, DenmarkDepartment of Biomedicine, Aarhus University, Aarhus, DenmarkDepartment of Rheumatology, Aarhus University Hospital, Aarhus, DenmarkInstitute of Clinical Medicine, Aarhus University, Aarhus, DenmarkDepartment of Biomedicine, Aarhus University, Aarhus, DenmarkDepartment of Biomedicine, Aarhus University, Aarhus, DenmarkIntroduction/objectivesIn 2012, hypocomplementemia was included in the classification criteria of systemic lupus erythematosus (SLE). The suggested measurement of C3 or C4 often reflect disease activity poorly. Our objective was to establish an assay measuring C3dg, which is generated following complement activation, and to evaluate the assay in a cross-sectional SLE cohort.MethodWe included SLE patients (n = 169) and controls (n = 170) and developed a modified C3dg assay where C3dg fragments were separated from the large plasma proteins by polyethylene glycol (PEG), and the supernatant containing the C3dg fragment was used for analysis in an antibody-based sandwich-type assay. Gel permeation chromatography and western blotting were used to establish the optimal conditions for PEG precipitation.Results16% PEG was optimal for separating C3dg from C3 and the larger protein fragments. The assay showed a high degree of stability when using EDTA plasma, and measurements correlated well with commercially available complement activation assays. SLE patients had higher concentrations in plasma of C3dg than controls (p < 0.05). ROC analysis showed that the C3dg activation fragment of C3 with an AUC of 0.96 (CI 0.94–0.98) was superior to C3 (AUC 0.52) in differentiating between patients and controls.ConclusionOur results present a modified assay for the measurement of C3dg. We demonstrate that C3dg was superior to conventional C3 measurements in discriminating SLE patients from controls. We suggest that C3dg should be considered as a complement activation measurement in the SLE classification criteria.http://journal.frontiersin.org/article/10.3389/fimmu.2018.00581/fullcomplement systemcomplement activationsystemic lupus erythematosusbiomarkerdiagnostics |
| spellingShingle | Anne Troldborg Anne Troldborg Lisbeth Jensen Bent Deleuran Bent Deleuran Kristian Stengaard-Pedersen Kristian Stengaard-Pedersen Steffen Thiel Jens Christian Jensenius The C3dg Fragment of Complement Is Superior to Conventional C3 as a Diagnostic Biomarker in Systemic Lupus Erythematosus Frontiers in Immunology complement system complement activation systemic lupus erythematosus biomarker diagnostics |
| title | The C3dg Fragment of Complement Is Superior to Conventional C3 as a Diagnostic Biomarker in Systemic Lupus Erythematosus |
| title_full | The C3dg Fragment of Complement Is Superior to Conventional C3 as a Diagnostic Biomarker in Systemic Lupus Erythematosus |
| title_fullStr | The C3dg Fragment of Complement Is Superior to Conventional C3 as a Diagnostic Biomarker in Systemic Lupus Erythematosus |
| title_full_unstemmed | The C3dg Fragment of Complement Is Superior to Conventional C3 as a Diagnostic Biomarker in Systemic Lupus Erythematosus |
| title_short | The C3dg Fragment of Complement Is Superior to Conventional C3 as a Diagnostic Biomarker in Systemic Lupus Erythematosus |
| title_sort | c3dg fragment of complement is superior to conventional c3 as a diagnostic biomarker in systemic lupus erythematosus |
| topic | complement system complement activation systemic lupus erythematosus biomarker diagnostics |
| url | http://journal.frontiersin.org/article/10.3389/fimmu.2018.00581/full |
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