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Castellanos-Molina V, Gomez A, Mejía M, Toquica A, Bernal-Macías S. Navigating the diagnostic maze: A case presentation of C1q vasculitis mimicking hypocomplementemic urticarial vasculitis in a patient with systemic lupus erythematosus. Lupus 2024; 33:886-891. [PMID: 38719778 DOI: 10.1177/09612033241253156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
In rare instances, patients with SLE may exhibit atypical clinical manifestations, such as Hypocomplementemic Urticarial Vasculitis, which can pose diagnostic challenges. Here, we present a case report of a 28-year-old female with a history of SLE with lupus nephritis clase IV who developed HUV-like symptoms, ultimately leading to a diagnosis of C1q Vasculitis. This case underscores the importance of considering C1q Vasculitis in SLE patients presenting with HUV-like features and highlights Rituximab as a promising therapeutic option for managing this rare condition.
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Affiliation(s)
- Veronica Castellanos-Molina
- Faculty of Medicine, Pontificia Universidad Javeriana, Bogotá D.C, Colombia
- Dermatology Unit, Hospital Universitario San Ignacio, Bogotá, Colombia
| | - Alejandra Gomez
- Faculty of Medicine, Pontificia Universidad Javeriana, Bogotá D.C, Colombia
- Internal Medicine Department, Hospital Universitario San Ignacio, Bogotá, Colombia
| | - Maddy Mejía
- Faculty of Medicine, Pontificia Universidad Javeriana, Bogotá D.C, Colombia
- Patology Department, Hospital Universitario San Ignacio, Bogotá, Colombia
| | - Alejandra Toquica
- Faculty of Medicine, Pontificia Universidad Javeriana, Bogotá D.C, Colombia
- Dermatology Unit, Hospital Universitario San Ignacio, Bogotá, Colombia
| | - Santiago Bernal-Macías
- Faculty of Medicine, Pontificia Universidad Javeriana, Bogotá D.C, Colombia
- Rheumatology Unit, Hospital Universitario San Ignacio, Bogotá, Colombia
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2
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Calatroni M, Moroni G, Conte E, Stella M, Reggiani F, Ponticelli C. Anti-C1q antibodies: a biomarker for diagnosis and management of lupus nephritis. A narrative review. Front Immunol 2024; 15:1410032. [PMID: 38938561 PMCID: PMC11208682 DOI: 10.3389/fimmu.2024.1410032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Accepted: 05/22/2024] [Indexed: 06/29/2024] Open
Abstract
Nephritis is a frequent and severe complication of Systemic Lupus Erythematous (SLE). The clinical course of lupus nephritis (LN) is usually characterized by alternating phases of remission and exacerbation. Flares of LN can lead to deterioration of kidney function, necessitating timely diagnosis and therapy. The presence of autoantibodies against C1q (anti-C1qAb) in the sera of SLE patients has been reported in various studies. Some research suggests that the presence and changes in the titer of anti-C1qAb may be associated with the development of LN, as well as with LN activity and renal flares. However, the exact role of anti-C1qAb in LN remains a subject of debate. Despite variability in the results of published studies, anti-C1qAb hold promise as noninvasive markers for assessing LN activity in SLE patients. Measuring anti-C1qAb levels could aid in diagnosing and managing LN during periods of both inactive disease and renal flares. Nevertheless, larger controlled trials with standardized laboratory assays are necessary to further establish the utility of anti-C1qAb in predicting the reactivation and remission of LN and guiding treatment strategies.
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Affiliation(s)
- Marta Calatroni
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- Nephrology and Dialysis Division, Humanitas Research Hospital, Institute for Research, Hospitalization and Health Care (IRCCS), Milan, Italy
| | - Gabriella Moroni
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- Nephrology and Dialysis Division, Humanitas Research Hospital, Institute for Research, Hospitalization and Health Care (IRCCS), Milan, Italy
| | - Emanuele Conte
- Nephrology and Dialysis Division, Humanitas Research Hospital, Institute for Research, Hospitalization and Health Care (IRCCS), Milan, Italy
- Department of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Matteo Stella
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- Nephrology and Dialysis Division, Humanitas Research Hospital, Institute for Research, Hospitalization and Health Care (IRCCS), Milan, Italy
| | - Francesco Reggiani
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
- Nephrology and Dialysis Division, Humanitas Research Hospital, Institute for Research, Hospitalization and Health Care (IRCCS), Milan, Italy
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3
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Bruschi M, Angeletti A, Prunotto M, Meroni PL, Ghiggeri GM, Moroni G, Sinico RA, Franceschini F, Fredi M, Vaglio A, Cavalli A, Scapozza L, Patel JJ, Tan JC, Lo KC, Cavagna L, Petretto A, Pratesi F, Migliorini P, Locatelli F, Pazzola G, Pesce G, Giannese D, Manfredi A, Ramirez GA, Esposito P, Murdaca G, Negrini S, Bui F, Trezzi B, Emmi G, Cavazzana I, Binda V, Fenaroli P, Pisan I, Montecucco C, Santoro D, Scolari F, Mescia F, Volpi S, Mosca M, Tincani A, Ravelli A, Murtas C, Candiano G, Caridi G, La Porta E, Verrina E. A critical view on autoantibodies in lupus nephritis: Concrete knowledge based on evidence. Autoimmun Rev 2024; 23:103535. [PMID: 38552995 DOI: 10.1016/j.autrev.2024.103535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/22/2024] [Accepted: 03/23/2024] [Indexed: 04/07/2024]
Abstract
Deposition of autoantibodies in glomeruli is a key factor in the development of lupus nephritis (LN). For a long time, anti-dsDNA and anti-C1q antibodies were thought to be the main cause of the kidney damage. However, recent studies have shown that the list of autoantibidies that have renal tropism and deposit in the kidney in LN is increasing and the link between anti-dsDNA and renal pathology is weak due to potential confounders. Aspecific bindings of dsDNA with cationic antibodies and of anti-dsDNA with several renal antigens such as actinin, laminin, entactin, and annexinA2 raised doubts about the specific target of these antibodies in the kidney. Moreover, the isotype of anti-dsDNA in SLE and LN has never received adequate interest until the recent observation that IgG2 are preponderant over IgG1, IgG3 and IgG4. Based on the above background, recent studies investigated the involvement of anti-dsDNA IgG2 and of other antibodies in LN. It was concluded that circulating anti-dsDNA IgG2 levels do not distinguish between LN versus non-renal SLE, and, in patients with LN, their levels do not change over time. Circulating levels of other antibodies such as anti-ENO1 and anti-H2 IgG2 were, instead, higher in LN vs non-renal SLE at the time of diagnosis and decreased following therapies. Finally, new classes of renal antibodies that potentially modify the anti-inflammatory response in the kidney are emerging as new co-actors in the pathogenetic scenario. They have been defined as 'second wave antibodies' for the link with detoxifying mechanisms limiting the oxidative stress in glomeruli that are classically stimulated in a second phase of inflammation. These findings have important clinical implications that may modify the laboratory approach to LN. Serum levels of anti-ENO1 and anti-H2 IgG2 should be measured in the follow up of patients for designing the length of therapies and identify those patients who respond to treatments. Anti-SOD2 could help to monitor and potentiate the anti-inflammatory response in the kidney.
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Affiliation(s)
- Maurizio Bruschi
- Laboratory of Molecular Nephrology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Andrea Angeletti
- Division of Nephrology, Dialysis and Transplantation, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Marco Prunotto
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, Geneva, Switzerland
| | - Pier Luigi Meroni
- Experimental Laboratory of Immunological and Rheumatologic Researches, Istituto Auxologico Italiano-Istituto di Ricovero e Cura a Carattere Scientifico, Milano, Italy.
| | - Gian Marco Ghiggeri
- Laboratory of Molecular Nephrology, IRCCS Istituto Giannina Gaslini, Genoa, Italy; Division of Nephrology, Dialysis and Transplantation, IRCCS Istituto Giannina Gaslini, Genoa, Italy.
| | - Gabriella Moroni
- Department of Biomedical Sciences, Humanitas University and IRCCS Humanitas Research Hospital, Milan, Italy
| | | | - Franco Franceschini
- Rheumatology and Clinical Immunology, ASST SpedaliCivili and Università of Brescia, Italy
| | - Micaela Fredi
- Rheumatology and Clinical Immunology, ASST SpedaliCivili and Università of Brescia, Italy
| | - Augusto Vaglio
- Department of Biomedical, Experimental and Clinical Sciences "Mario Serio", University of Firenze, and Nephrology and Dialysis Unit, Meyer Children's Hospital, Firenze, Italy
| | - Andrea Cavalli
- Institute for Research in Biomedicine, Università della Svizzera Italiana, Bellinzona, Switzerland; Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Leonardo Scapozza
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, Geneva, Switzerland
| | | | | | - Ken C Lo
- Nimble Therapeutics, Madison, WI, USA
| | - Lorenzo Cavagna
- Division of Rheumatology, University and IRCCS Policlinico S. Matteo, Pavia, Italy
| | - Andrea Petretto
- Core Facilities-Proteomics Laboratory, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Federico Pratesi
- Clinical Immunology Unit, Department of Internal Medicine, University of Pisa, Italy
| | - Paola Migliorini
- Clinical Immunology Unit, Department of Internal Medicine, University of Pisa, Italy
| | - Francesco Locatelli
- Division of Rheumatology, University and IRCCS Policlinico S. Matteo, Pavia, Italy
| | - Giulia Pazzola
- Nephrology and Dialysis, Arciospedale Santa Maria nuova, Reggio Emilia, Italy
| | - Giampaola Pesce
- Nephrology and Dialysis, Arciospedale Santa Maria nuova, Reggio Emilia, Italy
| | | | - Angelo Manfredi
- Unit of Internal Medicine and Immunology, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Giuseppe A Ramirez
- Unit of Internal Medicine and Immunology, IRCCS Ospedale San Raffaele, Milano, Italy
| | - Pasquale Esposito
- Division of Nephrology, University of Genoa and Policlinico San Martino, Genova, Italy
| | | | - Simone Negrini
- Department of Internal Medicine, University of Genoa, Italy
| | - Federica Bui
- Division of Nephrology, University of Genoa and Policlinico San Martino, Genova, Italy
| | - Barbara Trezzi
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Giacomo Emmi
- Lupus Clinic Department of biomedicine, University of Florence, University Hospital Careggi, Florence, Italy
| | - Ilaria Cavazzana
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, Geneva, Switzerland
| | - Valentina Binda
- Department of Biomedical, Experimental and Clinical Sciences "Mario Serio", University of Firenze, and Nephrology and Dialysis Unit, Meyer Children's Hospital, Firenze, Italy
| | - Paride Fenaroli
- Nephrology Unit, University Hospital, University of Parma, Parma, Italy
| | - Isabella Pisan
- Nephrology Unit, University Hospital, University of Parma, Parma, Italy
| | | | - Domenico Santoro
- Nephrology and Dialysis Unit, University of Messina and G Martino Hospital, Messina, Italy
| | - Francesco Scolari
- Division of Nephrology and Dialysis, ASST SpedaliCivili and Università of Brescia, Brescia, Italy
| | - Federica Mescia
- Division of Nephrology and Dialysis, ASST SpedaliCivili and Università of Brescia, Brescia, Italy
| | - Stefano Volpi
- Division of Paediatric Rheumatology and Scientific Institute for Research and Health Care, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Marta Mosca
- Rheumatologu Unit, Department of Clinical and Experimental Medicine, University of Pisa, Italy
| | - Angela Tincani
- Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, Geneva, Switzerland
| | - Angelo Ravelli
- Division of Paediatric Rheumatology and Scientific Institute for Research and Health Care, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Corrado Murtas
- Nephrology and Dialysis Unit, Ospedale Belcolle, 01100 Viterbo, Italy
| | - Giovanni Candiano
- Laboratory of Molecular Nephrology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Gianluca Caridi
- Laboratory of Molecular Nephrology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Edoardo La Porta
- Division of Nephrology, Dialysis and Transplantation, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Enrico Verrina
- Division of Nephrology, Dialysis and Transplantation, IRCCS Istituto Giannina Gaslini, Genoa, Italy
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Smets K, Van Baelen A, Sprangers B, De Haes P. Correct approach in urticarial vasculitis made early diagnosis of lupus nephritis possible: a case report. J Med Case Rep 2022; 16:314. [PMID: 35989318 PMCID: PMC9394059 DOI: 10.1186/s13256-022-03477-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 06/06/2022] [Indexed: 12/05/2022] Open
Abstract
Background Urticarial vasculitis is a clinicopathologic entity defined by recurrent episodes of urticarial lesions that persist > 24 hours and demonstrate the histopathologic features of leukocytoclastic vasculitis. The most important prognostic feature is the presence of normo- or hypocomplementemia. In the latter, patients are much more likely to have systemic manifestations. Urticarial vasculitis is most often idiopathic, but it can arise in association with autoimmune connective diseases, cryoglobulinemia, infections, medications, and hematologic malignancies. Case presentation We present the case of a 61-year-old Caucasian woman with a skin eruption that consisted of erythematous plaques on the trunk and limbs that lasted > 24 hours but were asymptomatic. The skin eruption had an acute onset and persisted for 3 months upon initial presentation in our dermatology department. A punch biopsy showed signs of a leukocytoclastic vasculitis in the superficial dermis. On laboratory examination, signs of activation of the complement system were found with low complement C3, C4, and C1q, and with a high anti-C1q antibody titer. The clinical, histological, and lab results fit the diagnosis of hypocomplementemic urticarial vasculitis. There was also a positive antinuclear factor with elevated U1 small nuclear ribonucleoprotein and high double-stranded DNA determined by Farr method. On urinalysis, marked proteinuria and massive hematuria were found. Kidney biopsy showed focal crescentic and focal mesangial type of glomerular damage with a full-blown positivity of immunoglobulin A, immunoglobulin G, and C1q, leading to lupus nephritis class III-A (according to the International Society of Nephrology/Renal Pathology Society 2003 classification of lupus nephritis). The patient was treated with hydroxychloroquine, corticosteroids, and low-dose intravenous cyclophosphamide (Euro-Lupus regimen) as remission-inducing agent, followed by azathioprine as remission-maintaining agent. This treatment regimen gave good results, with total clearance of the skin lesions and remission of the lupus nephritis. Conclusion Clinicopathologic recognition of urticarial vasculitis with correct screening for extracutaneous disease can lead to early diagnosis of serious organ involvement and thereby improve prognosis for the patient.
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Rabatscher PA, Trendelenburg M. Anti-C1q autoantibodies from systemic lupus erythematosus patients enhance CD40-CD154-mediated inflammation in peripheral blood mononuclear cells in vitro. Clin Transl Immunology 2022; 11:e1408. [PMID: 35928801 PMCID: PMC9345742 DOI: 10.1002/cti2.1408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 05/09/2022] [Accepted: 07/14/2022] [Indexed: 01/03/2023] Open
Abstract
Objectives Systemic lupus erythematosus (SLE) is a clinically heterogeneous autoimmune disease with complex pathogenic mechanisms. Complement C1q has been shown to play a major role in SLE, and autoantibodies against C1q (anti‐C1q) are strongly associated with SLE disease activity and severe lupus nephritis suggesting a pathogenic role for anti‐C1q. Whereas C1q alone has anti‐inflammatory effects on human monocytes and macrophages, C1q/anti‐C1q complexes favor a pro‐inflammatory phenotype. This study aimed to elucidate the inflammatory effects of anti‐C1q on peripheral blood mononuclear cells (PBMCs). Methods Isolated monocytes, isolated T cells and bulk PBMCs of healthy donors with or without concomitant T cell activation were exposed to C1q or complexes of C1q and SLE patient‐derived anti‐C1q (C1q/anti‐C1q). Functional consequences of C1q/anti‐C1q on cells were assessed by determining cytokine secretion, monocyte surface marker expression, T cell activation and proliferation. Results Exposure of isolated T cells to C1q or C1q/anti‐C1q did not affect their activation and proliferation. However, unspecific T cell activation in PBMCs in the presence of C1q/anti‐C1q resulted in increased TNF, IFN‐γ and IL‐10 secretion compared with C1q alone. Co‐culture and inhibition experiments showed that the inflammatory effect of C1q/anti‐C1q on PBMCs was due to a direct CD40–CD154 interaction between activated T cells and C1q/anti‐C1q‐primed monocytes. The CD40‐mediated inflammatory reaction of monocytes involves TRAF6 and JAK3‐STAT5 signalling. Conclusion In conclusion, C1q/anti‐C1q have a pro‐inflammatory effect on monocytes that depends on T cell activation and CD40–CD154 signalling. This signalling pathway could serve as a therapeutic target for anti‐C1q‐mediated inflammation.
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Affiliation(s)
| | - Marten Trendelenburg
- Laboratory of Clinical Immunology, Department of Biomedicine University of Basel Basel Switzerland.,Division of Internal Medicine University Hospital Basel Basel Switzerland
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Fernandez-Ruiz R, Belmont HM. The role of anticomplement therapy in lupus nephritis. Transl Res 2022; 245:1-17. [PMID: 35158097 DOI: 10.1016/j.trsl.2022.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 10/19/2022]
Abstract
The complement system plays crucial roles in homeostasis and host defense against microbes. Deficiency of early complement cascade components has been associated with increased susceptibility to systemic lupus erythematosus (SLE), whereas excessive complement consumption is a hallmark of this disease. Although enhanced classical pathway activation by immune complexes was initially thought to be the main contributor to lupus nephritis (LN) pathogenesis, an increasing body of evidence has suggested the alternative and the lectin pathways are also involved. Therapeutic agents targeting complement activation have been used in LN patients and clinical trials are ongoing. We review the mechanisms by which complement system dysregulation contributes to renal injury in SLE and summarize the latest evidence on the use of anticomplement agents to manage this condition.
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Affiliation(s)
- Ruth Fernandez-Ruiz
- Division of Rheumatology, NYU Grossman School of Medicine, New York, New York
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Kleer JS, Rabatscher PA, Weiss J, Leonardi J, Vogt SB, Kieninger-Gräfitsch A, Chizzolini C, Huynh-Do U, Ribi C, Trendelenburg M. Epitope-Specific Anti-C1q Autoantibodies in Systemic Lupus Erythematosus. Front Immunol 2022; 12:761395. [PMID: 35087514 PMCID: PMC8788646 DOI: 10.3389/fimmu.2021.761395] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
Objective In patients with systemic lupus erythematosus (SLE) complement C1q is frequently targeted by autoantibodies (anti-C1q), that correlate best with active renal disease. Anti-C1q bind to largely unknown epitopes on the collagen-like region (CLR) of this highly functional molecule. Here we aimed at exploring the role of epitope-specific anti-C1q in SLE patients. Methods First, 22 sera of SLE patients, healthy controls and anti-C1q positive patients without SLE were screened for anti-C1q epitopes by a PEPperMAP® microarray, expressing CLR of C1q derived peptides with one amino acid (AA) shift in different lengths and conformations. Afterwards, samples of 378 SLE patients and 100 healthy blood donors were analyzed for antibodies against the identified epitopes by peptide-based ELISA. Relationships between peptide-specific autoantibodies and SLE disease manifestations were explored by logistic regression models. Results The epitope mapping showed increased IgG binding to three peptides of the C1q A- and three of the C1q B-chain. In subsequent peptide-based ELISAs, SLE sera showed significantly higher binding to two N-terminally located C1q A-chain peptides than controls (p < 0.0001), but not to the other peptides. While anti-C1q were associated with a broad spectrum of disease manifestations, some of the peptide-antibodies were associated with selected disease manifestations, and antibodies against the N-terminal C1q A-chain showed a stronger discrimination between SLE and controls than conventional anti-C1q. Conclusion In this large explorative study anti-C1q correlate with SLE overall disease activity. In contrast, peptide-antibodies are associated with specific aspects of the disease suggesting epitope-specific effects of anti-C1q in patients with SLE.
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Affiliation(s)
- Jessica S Kleer
- Laboratory of Clinical Immunology, Department of Biomedicine, University of Basel, Basel, Switzerland.,Division of Internal Medicine, University Hospital, Basel, Switzerland
| | - Pascal A Rabatscher
- Laboratory of Clinical Immunology, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Jessica Weiss
- Laboratory of Clinical Immunology, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Joel Leonardi
- Laboratory of Clinical Immunology, Department of Biomedicine, University of Basel, Basel, Switzerland.,Division of Internal Medicine, University Hospital, Basel, Switzerland
| | - Severin B Vogt
- Department of Clinical Pharmacology and Toxicology, University Hospital, Basel, Switzerland
| | | | - Carlo Chizzolini
- Department of Pathology and Immunology, University Hospital, Geneva, Switzerland
| | - Uyen Huynh-Do
- Department of Nephrology and Hypertension, University Hospital, Bern, Switzerland
| | - Camillo Ribi
- Division of Immunology and Allergy, Department of Internal Medicine, University Hospital, Lausanne, Switzerland
| | - Marten Trendelenburg
- Laboratory of Clinical Immunology, Department of Biomedicine, University of Basel, Basel, Switzerland.,Division of Internal Medicine, University Hospital, Basel, Switzerland
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8
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Circulating C1q levels in health and disease, more than just a biomarker. Mol Immunol 2021; 140:206-216. [PMID: 34735869 DOI: 10.1016/j.molimm.2021.10.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 10/03/2021] [Accepted: 10/11/2021] [Indexed: 12/21/2022]
Abstract
C1q is the recognition molecule of the classical pathway of the complement system. By binding to its targets, such as antigen-bound immunoglobulins or C-reactive protein, C1q contributes to the innate defense against infections. However, C1q also plays several other roles beyond its traditional role in complement activation. Circulating levels of C1q are determined in routine diagnostics as biomarker in several diseases. Decreased C1q levels are present in several autoimmune conditions. The decreased levels reflect the consumption of C1q by complement activation and serves as a biomarker for disease activity. In contrast, increased C1q levels are present in infectious and inflammatory diseases and may serve as a diagnostic biomarker. The increased levels of C1q are still incompletely understood but are suggested to modulate the adaptive immune response as C1q is known to impact on the maturation status of antigen-presenting cells and C1q impacts directly on T cells leading to decreased T-cell activity in high C1q conditions. In this review, we provide a comprehensive overview of the current literature on circulating levels of C1q in health and disease, and discuss how C1q can both protect against infections as well as maintain tolerance by regulating adaptive immunity.
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9
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Trendelenburg M. Autoantibodies against complement component C1q in systemic lupus erythematosus. Clin Transl Immunology 2021; 10:e1279. [PMID: 33968409 PMCID: PMC8082710 DOI: 10.1002/cti2.1279] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/19/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is the archetype of a systemic autoimmune disease, but the multifaceted pathogenic mechanisms leading to inflammation and organ damage are not fully understood. Homozygous deficiency of complement C1q, the first component of the classical pathway of complement, is strongly associated with the development of SLE, thus pointing at a primarily protective role of C1q. However, while most SLE patients do not have hereditary C1q deficiency, there is indirect evidence for the importance of C1q in the inflammatory processes of the disease, including hypocomplementemia as a result of activation via the classical pathway, deposition of C1q in affected tissues and the occurrence of autoantibodies against C1q (anti‐C1q). The growing body of knowledge on anti‐C1q led to the establishment of a biomarker that is used in the routine clinical care of SLE patients. Exploring the binding characteristics of anti‐C1q allows to understand the mechanisms, that lead to the expression of relevant autoantigenic structures and the role of genetic as well as environmental factors. Lastly, the analysis of the pathophysiological consequences of anti‐C1q is of importance because C1q, the target of anti‐C1q, is a highly functional molecule whose downstream effects are altered by the binding of the autoantibody. This review summarises current study data on anti‐C1q and their implications for the understanding of SLE.
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Affiliation(s)
- Marten Trendelenburg
- Division of Internal Medicine University Hospital Basel Basel Switzerland.,Clinical Immunology Department of Biomedicine University of Basel Basel Switzerland
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10
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The clinical and serological associations of hypocomplementemia in a longitudinal sle cohort. Semin Arthritis Rheum 2020; 50:1081-1086. [PMID: 32916558 DOI: 10.1016/j.semarthrit.2020.06.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 04/24/2020] [Accepted: 06/17/2020] [Indexed: 01/07/2023]
Abstract
BACKGROUND In SLE, low complement is an important serological manifestation. Recent classification criteria include hypocomplementemia and one gives additional weight if both C3 and C4 are low. We evaluated patients with a history of, and those with persistently, low complement. As complement activation occurs in the antiphospholipid antibody syndrome, an analysis was also performed on those with positive antiphospholipid antibodies to evaluate thrombotic outcomes. METHODS In a longitudinal SLE cohort, organ manifestations, damage, C3, C4 and antiphospholipid antibodies were assessed quarterly. Using univariate and multivariate methods we compared those with and without a history of low C3, low C4 and both. We evaluated those who had a history of low complement at any time point, and those who had persistent hypocomplementemia. Further analysis considered thrombotic outcomes in patients with positive antiphospholipid antibodies and a history of low complement. RESULTS 2399 patients were evaluated. Fifty-five percent had a history of low C3 and 47% low C4; 83 (4%) had persistently low C3 and 65 (3.2%) had persistently low C4. Hematological, renal and serological abnormalities associated with a history of low C3 but not low C4. With anticardiolipin antibodies, a history of hypocomplementemia (both C3 and C4 low) associated with stroke and deep venous thrombosis. CONCLUSION Low C4 was a weak marker in terms of the associated clinical and serological manifestations. Low C3 associated with renal involvement and poor renal outcomes. A history of both low C3 and C4 associated with stroke in the presence of lupus anticoagulant or anticardiolipin antibodies, and low C4 with digital gangrene (with lupus anticoagulant).
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11
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Csorba K, Schirmbeck LA, Tuncer E, Ribi C, Roux-Lombard P, Chizzolini C, Huynh-Do U, Vanhecke D, Trendelenburg M. Anti-C1q Antibodies as Occurring in Systemic Lupus Erythematosus Could Be Induced by an Epstein-Barr Virus-Derived Antigenic Site. Front Immunol 2019; 10:2619. [PMID: 31787984 PMCID: PMC6853867 DOI: 10.3389/fimmu.2019.02619] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 10/21/2019] [Indexed: 01/08/2023] Open
Abstract
Previous infection with Epstein-Barr virus (EBV) is believed to trigger autoimmunity and to drive autoantibody generation as occurring in patients with systemic lupus erythematosus (SLE). Complement C1q and autoantibodies targeting it (anti-C1q) are also considered to be involved in the pathogenesis of SLE, independently of the impact of environmental insults. Still, the circumstances under which these autoantibodies arise remain elusive. By studying a major antigenic site of C1q targeted by anti-C1q (A08), we aimed to determine environmental factors and possible mechanisms leading to the development of anti-C1q. First, we determined antigenic residues of A08 that were critical for the binding of anti-C1q; importantly, we found the binding to depend on amino-acid-identity. Anti-C1q of SLE patients targeting these critical antigenic residues specifically cross-reacted with the EBV-related EBNA-1 (Epstein-Barr virus nuclear antigen 1)-derived peptide EBNA348. In a cohort of 180 SLE patients we confirmed that patients that were seropositive for EBV and recognized the EBNA348 peptide had increased levels of anti-A08 and anti-C1q, respectively. The correlation of anti-EBNA348 with anti-A08 levels was stronger in SLE patients than in matched healthy controls. Finally, EBNA348 peptide-immunization of C1q−/− mice induced the generation of cross-reactive antibodies which recognized both the A08 epitope of C1q and intact C1q. These findings suggest that anti-C1q in SLE patients could be induced by an EBV-derived epitope through molecular mimicry, thereby further supporting the pathogenic role of EBV in the development of SLE. Considering the role of C1q and anti-C1q, modifying the anti-EBV response might be a promising strategy to improve the course of the disease.
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Affiliation(s)
- Kinga Csorba
- Clinical Immunology, Department of Biomedicine and Division of Internal Medicine, University and University Hospital Basel, Basel, Switzerland
| | - Lucia A Schirmbeck
- Clinical Immunology, Department of Biomedicine and Division of Internal Medicine, University and University Hospital Basel, Basel, Switzerland
| | - Eylul Tuncer
- Clinical Immunology, Department of Biomedicine and Division of Internal Medicine, University and University Hospital Basel, Basel, Switzerland
| | - Camillo Ribi
- Immunology and Allergy, Department of Internal Medicine, University Hospital Lausanne, Lausanne, Switzerland
| | - Pascale Roux-Lombard
- Division of Immunology and Allergy, Department of Medicine, University Hospital and University of Geneva, Geneva, Switzerland
| | - Carlo Chizzolini
- Division of Immunology and Allergy, Department of Medicine, University Hospital and University of Geneva, Geneva, Switzerland
| | - Uyen Huynh-Do
- Division of Nephrology and Hypertension, University Hospital Bern, Bern, Switzerland
| | - Dominique Vanhecke
- Clinical Immunology, Department of Biomedicine and Division of Internal Medicine, University and University Hospital Basel, Basel, Switzerland
| | - Marten Trendelenburg
- Clinical Immunology, Department of Biomedicine and Division of Internal Medicine, University and University Hospital Basel, Basel, Switzerland
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12
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Dumestre-Pérard C, Clavarino G, Colliard S, Cesbron JY, Thielens NM. Antibodies targeting circulating protective molecules in lupus nephritis: Interest as serological biomarkers. Autoimmun Rev 2018; 17:890-899. [PMID: 30009962 DOI: 10.1016/j.autrev.2018.03.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 03/15/2018] [Indexed: 12/15/2022]
Abstract
Lupus nephritis (LN) is one of the most frequent and severe manifestations of systemic lupus erythematosus (SLE), considered as the major predictor of poor prognosis. An early diagnosis of LN is a real challenge in the management of SLE and has an important implication in guiding treatments. In clinical practice, conventional parameters still lack sensitivity and specificity for detecting ongoing disease activity in lupus kidneys and early relapse of nephritis. LN is characterized by glomerular kidney injury, essentially due to deposition of immune complexes involving autoantibodies against cellular components and circulating proteins. One of the possible mechanisms of induction of autoantibodies in SLE is a defect in apoptotic cells clearance and subsequent release of intracellular autoantigens. Autoantibodies against soluble protective molecules involved in the uptake of dying cells, including complement proteins and pentraxins, have been described. In this review, we present the main autoantibodies found in LN, with a focus on the antibodies against these protective molecules. We also discuss their pathogenic role and conclude with their potential interest as serological biomarkers in LN.
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Affiliation(s)
- Chantal Dumestre-Pérard
- Laboratoire d'Immunologie, Pôle de Biologie, CHU Grenoble Alpes, CS 10217, 38043 Grenoble Cedex 9, France; BNI TIMC-IMAG, UMR5525, CNRS-Université Grenoble Alpes, BP170, 38042 Grenoble Cedex 9, France.
| | - Giovanna Clavarino
- Laboratoire d'Immunologie, Pôle de Biologie, CHU Grenoble Alpes, CS 10217, 38043 Grenoble Cedex 9, France; BNI TIMC-IMAG, UMR5525, CNRS-Université Grenoble Alpes, BP170, 38042 Grenoble Cedex 9, France
| | - Sophie Colliard
- Laboratoire d'Immunologie, Pôle de Biologie, CHU Grenoble Alpes, CS 10217, 38043 Grenoble Cedex 9, France
| | - Jean-Yves Cesbron
- Laboratoire d'Immunologie, Pôle de Biologie, CHU Grenoble Alpes, CS 10217, 38043 Grenoble Cedex 9, France; BNI TIMC-IMAG, UMR5525, CNRS-Université Grenoble Alpes, BP170, 38042 Grenoble Cedex 9, France
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13
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Autoantibodies against complement components in systemic lupus erythematosus – role in the pathogenesis and clinical manifestations. Lupus 2017; 26:1550-1555. [DOI: 10.1177/0961203317709347] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Many complement structures and a number of additional factors, i.e. autoantibodies, receptors, hormones and cytokines, are implicated in the complex pathogenesis of systemic lupus erythematosus. Genetic defects in the complement as well as functional deficiency due to antibodies against its components lead to different pathological conditions, usually clinically presented. Among them hypocomplementemic urticarial vasculitis, different types of glomerulonephritis as dense deposit disease, IgA nephropathy, atypical haemolytic uremic syndrome and lupus nephritis are very common. These antibodies cause conformational changes leading to pathological activation or inhibition of complement with organ damage and/or limited capacity of the immune system to clear immune complexes and apoptotic debris. Finally, we summarize the role of complement antibodies in the pathogenesis of systemic lupus erythematosus and discuss the mechanism of some related clinical conditions such as infections, thyroiditis, thrombosis, acquired von Willebrand disease, etc.
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14
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Abstract
C1q is the first component of the classical complement pathway. Both clinically validated in-house ELISA assays as well as commercial ELISA kits are used for detection of anti-C1q antibodies. Anti-C1q autoantibodies can be detected in a wide range of autoimmune diseases and are highly sensitive for hypocomplementemic uticarial vasculitis. In SLE, anti-C1q are strongly associated with proliferative lupus nephritis, and their absence carries a negative predictive value for development of lupus nephritis of close to 100%. Anti-C1q in combination with anti-dsDNA and low complement has the strongest serological association with renal involvement. The anti-C1q titers correlate with global disease activity scores in patients with renal involvement, and higher titers seem to precede renal flares. After the successful treatment of a renal flare, anti-C1q has the tendency to decrease or even become undetectable. The main obstacle to the inclusion of anti-C1q in the classification criteria and clinical management of SLE is the lack of standardized laboratory assays.
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Affiliation(s)
- G Stojan
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - M Petri
- Division of Rheumatology, Johns Hopkins University, Baltimore, MD, USA
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15
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Goilav B, Putterman C, Rubinstein TB. Biomarkers for kidney involvement in pediatric lupus. Biomark Med 2016; 9:529-43. [PMID: 26079958 DOI: 10.2217/bmm.15.25] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Lupus nephritis (LN), the renal involvement in systemic lupus erythematosus, is currently diagnosed by histopathology obtained by percutaneous renal biopsy and is associated with increased morbidity and mortality in both adults and children. LN is more prevalent and severe in children, requiring aggressive and prolonged immunosuppression. The consequences of the diagnosis and its treatment have devastating long-term effects on the growth, well-being and quality of life of affected children. The paucity of reliable clinical indicators of the presence and severity of renal involvement have contributed to a halt in the reduction of progression to end-stage renal disease in recent years. Here, we discuss the recent development of biomarkers in the management of LN and their role as therapeutic targets.
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Affiliation(s)
- Beatrice Goilav
- Children's Hospital at Montefiore, Department of Pediatrics, Division of Nephrology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA
| | - Chaim Putterman
- Division of Rheumatology & Department of Microbiology & Immunology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA
| | - Tamar B Rubinstein
- Children's Hospital at Montefiore, Department of Pediatrics, Division of Rheumatology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA
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16
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Abeed AA, Katat A, El-Gohary IE, Hamam OA. Circulating serum anti-C1q antibody: correlation with clinical and histopathological activity in patients with proliferative lupus nephritis. THE EGYPTIAN JOURNAL OF INTERNAL MEDICINE 2016. [DOI: 10.4103/1110-7782.182950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Thanei S, Trendelenburg M. Anti-C1q Autoantibodies from Systemic Lupus Erythematosus Patients Induce a Proinflammatory Phenotype in Macrophages. THE JOURNAL OF IMMUNOLOGY 2016; 196:2063-74. [PMID: 26829984 DOI: 10.4049/jimmunol.1501659] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 12/21/2015] [Indexed: 12/25/2022]
Abstract
Anti-C1q autoantibodies (anti-C1q) are frequently found in patients with systemic lupus erythematosus (SLE) and correlate with the occurrence of proliferative lupus nephritis. A previous study of anti-C1q in experimental lupus nephritis demonstrated an important role for FcγRs in the pathogenesis of lupus nephritis, suggesting a direct effect on phagocytes. Therefore, we developed an in vitro model to study the effect of SLE patient-derived anti-C1q bound to immobilized C1q (imC1q) on human monocyte-derived macrophages (HMDMs) obtained from healthy donors and SLE patients. HMDMs were investigated by analyzing the cell morphology, LPS-induced cytokine profile, surface marker expression, and phagocytosis rate of apoptotic Jurkat cells. Morphologically, bound anti-C1q induced cell aggregations of HMDMs compared with imC1q or IgG alone. In addition, anti-C1q reversed the effect of imC1q alone, shifting the LPS-induced cytokine release toward a proinflammatory response. FcγR-blocking experiments revealed that the secretion of proinflammatory cytokines was mediated via FcγRII. The anti-C1q-induced inflammatory cytokine profile was accompanied by a downregulation of CD163 and an upregulation of LPS-induced CD80, CD274, and MHC class II. Finally, HMDMs primed on bound anti-C1q versus imC1q alone displayed a significantly lower phagocytosis rate of early and late apoptotic cells accompanied by a reduced Mer tyrosine kinase expression. Interestingly, anti-C1q-dependent secretion of proinflammatory cytokines was similar in SLE patient-derived cells, with the exception that IL-10 was slightly increased. In conclusion, anti-C1q induced a proinflammatory phenotype in HMDMs reversing the effects of imC1q alone. This effect might exacerbate underlying pathogenic mechanisms in lupus nephritis.
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Affiliation(s)
- Sophia Thanei
- Laboratory of Clinical Immunology, University Hospital Basel, CH-4031 Basel, Switzerland; and
| | - Marten Trendelenburg
- Laboratory of Clinical Immunology, University Hospital Basel, CH-4031 Basel, Switzerland; and Division of Internal Medicine, University Hospital Basel, CH-4031 Basel, Switzerland
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18
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Stoyanova V, Bogoeva V, Petrova L, Tchorbadjieva M, Petrova S, Georgieva V, Georgiev G, Deliyska B, Vasilev V, Tsacheva I. Autoantigenicity of human C1q is associated with increased hydrophobicity due to conformational transitions in the globular heads. MOLECULAR BIOSYSTEMS 2016; 11:1370-7. [PMID: 25813365 DOI: 10.1039/c5mb00021a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We analyzed the structural features of C1q that underlie its autoantigenicity by means of a model system using the amphiphilic polyzwitterion (PZ), poly(ethylene oxide-b-N,N-dimethyl(methacryloyloxyethyl) ammonium propanesulfonate) in the process of C1q immobilization. The source of anti-C1q autoantibodies was human sera from patients with Lupus Nephritis (LN). Both analyzed concentrations of PZ, 25 mM and 50 mM, were found to be applicable for inducing conformational transitions which resulted in increased recognition of C1q and the globular domain of its B polypeptide chain, designated ghB, by the LN autoantibodies. The registered conformational transitions displayed a hydrophobic enhancement of the protein microenvironment due to the presence of hydrophobic binding sites in ghB which consequently affected the autoantigenicity of the whole C1q molecule.
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Affiliation(s)
- Vishnya Stoyanova
- Sofia University, Faculty of Biology, Dept. of Biochemistry, 8 D. Tsankov St., 1164 Sofia, Bulgaria.
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Dema B, Charles N. Autoantibodies in SLE: Specificities, Isotypes and Receptors. Antibodies (Basel) 2016; 5:antib5010002. [PMID: 31557984 PMCID: PMC6698872 DOI: 10.3390/antib5010002] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 12/09/2015] [Accepted: 12/11/2015] [Indexed: 12/23/2022] Open
Abstract
Systemic Lupus Erythematosus (SLE) is characterized by a wide spectrum of auto-antibodies which recognize several cellular components. The production of these self-reactive antibodies fluctuates during the course of the disease and the involvement of different antibody-secreting cell populations are considered highly relevant for the disease pathogenesis. These cells are developed and stimulated through different ways leading to the secretion of a variety of isotypes, affinities and idiotypes. Each of them has a particular mechanism of action binding to a specific antigen and recognized by distinct receptors. The effector responses triggered lead to a chronic tissue inflammation. DsDNA autoantibodies are the most studied as well as the first in being characterized for its pathogenic role in Lupus nephritis. However, others are of growing interest since they have been associated with other organ-specific damage, such as anti-NMDAR antibodies in neuropsychiatric clinical manifestations or anti-β2GP1 antibodies in vascular symptomatology. In this review, we describe the different auto-antibodies reported to be involved in SLE. How autoantibody isotypes and affinity-binding to their antigen might result in different pathogenic responses is also discussed.
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Affiliation(s)
- Barbara Dema
- Centre de Recherche sur l'Inflammation, INSERM UMR1149, CNRS ERL8252, Université Paris Diderot, Sorbonne Paris Cité, Faculté de Médecine site Bichat, Laboratoire d'Excellence Inflamex, DHU FIRE, Paris 75018, France.
| | - Nicolas Charles
- Centre de Recherche sur l'Inflammation, INSERM UMR1149, CNRS ERL8252, Université Paris Diderot, Sorbonne Paris Cité, Faculté de Médecine site Bichat, Laboratoire d'Excellence Inflamex, DHU FIRE, Paris 75018, France.
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20
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Birmingham DJ, Bitter JE, Ndukwe EG, Dials S, Gullo TR, Conroy S, Nagaraja HN, Rovin BH, Hebert LA. Relationship of Circulating Anti-C3b and Anti-C1q IgG to Lupus Nephritis and Its Flare. Clin J Am Soc Nephrol 2015; 11:47-53. [PMID: 26700439 DOI: 10.2215/cjn.03990415] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 10/01/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Autoantibodies to complement C1q (anti-C1q) are associated with the diagnosis of lupus nephritis. In this study, we compare anti-C1q IgG with another complement autoantibody, anti-C3b IgG, as a biomarker of lupus nephritis and lupus nephritis flare. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Our investigation involved the Ohio SLE Study, a prospective observational cohort of patients with recurrently active lupus who were followed bimonthly. Serum anti-C1q and anti-C3b IgG levels were assessed cross-sectionally by ELISA in 40 normal controls and 114 patients in the Ohio SLE Study (41 nonrenal and 73 lupus nephritis) at study entry, and longitudinally in a subset of patients in the Ohio SLE Study with anti-C1q-positive lupus nephritis in samples collected every 2 months for 8 months leading up to lupus nephritis flare (n=16 patients). RESULTS In the cross-sectional analysis, compared with anti-C1q IgG, anti-C3b IgG was less sensitive (36% versus 63%) but more specific (98% versus 71%) for lupus nephritis. Only anti-C3b IgG was associated with patients with lupus nephritis who experienced at least one lupus nephritis flare during the Ohio SLE Study period (P<0.01). In the longitudinal analysis, circulating levels of anti-C1q IgG increased at the time of lupus nephritis flare only in patients who were anti-C3b positive (P=0.02), with significant increases occurring from 6 (38% increase) and 4 months (41% increase) before flare. Anti-C3b IgG levels also trended up at lupus nephritis flare, although the change did not reach statistical significance (P=0.07). Neither autoantibody increased 2 months before flare. CONCLUSIONS Although not as prevalent as anti-C1q IgG, anti-C3b IgG showed nearly complete specificity for lupus nephritis. The presence of anti-C3b IgG identified patients with lupus nephritis who were prone to flare and in whom serial measurements of markers associated with complement, such as anti-C1q IgG, may be useful to monitor lupus nephritis activity.
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Affiliation(s)
- Daniel J Birmingham
- Department of Medicine and Davis Heart and Lung Research Institute, Ohio State University Medical Center, Columbus, Ohio; and
| | - Joshua E Bitter
- Department of Medicine and Davis Heart and Lung Research Institute, Ohio State University Medical Center, Columbus, Ohio; and
| | - Ezinne G Ndukwe
- Department of Medicine and Davis Heart and Lung Research Institute, Ohio State University Medical Center, Columbus, Ohio; and
| | - Sarah Dials
- Department of Medicine and Davis Heart and Lung Research Institute, Ohio State University Medical Center, Columbus, Ohio; and
| | - Terese R Gullo
- Department of Medicine and Davis Heart and Lung Research Institute, Ohio State University Medical Center, Columbus, Ohio; and
| | - Sara Conroy
- Division of Biostatistics, Ohio State University College of Public Health, Columbus, Ohio
| | - Haikady N Nagaraja
- Division of Biostatistics, Ohio State University College of Public Health, Columbus, Ohio
| | - Brad H Rovin
- Department of Medicine and Davis Heart and Lung Research Institute, Ohio State University Medical Center, Columbus, Ohio; and
| | - Lee A Hebert
- Department of Medicine and Davis Heart and Lung Research Institute, Ohio State University Medical Center, Columbus, Ohio; and
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21
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Thanei S, Vanhecke D, Trendelenburg M. Anti-C1q autoantibodies from systemic lupus erythematosus patients activate the complement system via both the classical and lectin pathways. Clin Immunol 2015; 160:180-7. [DOI: 10.1016/j.clim.2015.06.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/22/2015] [Accepted: 06/26/2015] [Indexed: 12/29/2022]
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23
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Vasculitis secondary to anti-C1q antibodies induced by Toxocariasis. Infection 2015; 43:755-8. [PMID: 25808264 DOI: 10.1007/s15010-015-0766-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 03/18/2015] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Vasculitides occurring during parasitic infection are rare and may imply different mechanisms. METHODS A case report of cutaneous vasculitis and visceral damage during a larva migrans syndrome. RESULTS We report the case of a 64-year-old man who developed a purpura along with fever, respiratory failure, abdominal pain and myalgia. Immunological screening showed a high titer of both antinuclear antibodies and anti-double-stranded DNA antibodies along with anti-C1q antibodies. Toxocara canis serology returned highly positive with a positive western-blot. The use of antiparasitic drugs in combination with corticosteroids resulted in a dramatic improvement in the patient's condition. CONCLUSIONS Clinicians should be aware of the systemic complications that may occur during Toxocara canis infection, including vasculitis and immunological disorder.
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Bruschi M, Galetti M, Sinico RA, Moroni G, Bonanni A, Radice A, Tincani A, Pratesi F, Migliorini P, Murtas C, Franceschini F, Trezzi B, Brunini F, Gatti R, Tardanico R, Barbano G, Piaggio G, Messa P, Ravani P, Scolari F, Candiano G, Martini A, Allegri L, Ghiggeri GM. Glomerular Autoimmune Multicomponents of Human Lupus Nephritis In Vivo (2): Planted Antigens. J Am Soc Nephrol 2014; 26:1905-24. [PMID: 25398787 DOI: 10.1681/asn.2014050493] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 09/30/2014] [Indexed: 02/05/2023] Open
Abstract
Glomerular planted antigens (histones, DNA, and C1q) are potential targets of autoimmunity in lupus nephritis (LN). However, the characterization of these antigens in human glomeruli in vivo remains inconsistent. We eluted glomerular autoantibodies recognizing planted antigens from laser-microdissected renal biopsy samples of 20 patients with LN. Prevalent antibody isotypes were defined, levels were determined, and glomerular colocalization was investigated. Renal and circulating antibodies were matched, and serum levels were compared in 104 patients with LN, 84 patients with SLE without LN, and 50 patients with rheumatoid arthritis (RA). Autoantibodies against podocyte antigens (anti-α-enolase/antiannexin AI) were also investigated. IgG2 autoantibodies against DNA, histones (H2A, H3, and H4), and C1q were detected in 50%, 55%, and 70% of biopsy samples, respectively. Anti-DNA IgG3 was the unique non-IgG2 anti-DNA deposit, and anti-C1q IgG4 was mainly detected in subepithelial membranous deposits. Anti-H3, anti-DNA, and anti-C1q IgG2 autoantibodies were also prevalent in LN serum, which also contained IgG3 against the antigen panel and anti-C1q IgG4. Serum and glomerular levels of autoantibodies were not strictly associated. High serum levels of all autoantibodies detected, including anti-α-enolase and antiannexin AI, identified LN versus SLE and RA. Anti-H3 and anti-α-enolase IgG2 levels had the most remarkable increase in LN serum and represented a discriminating feature of LN in principal component analysis. The highest levels of these two autoantibodies were also associated with proteinuria>3.5 g/24 hours and creatinine>1.2 mg/dl. Our findings suggest that timely autoantibody characterization might allow outcome prediction and targeted therapies for patients with nephritis.
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Affiliation(s)
| | - Maricla Galetti
- Departments of Clinical and Experimental Medicine and Italian Workers' Compensation Authority (INAIL) Research Center, University of Parma, Parma, Italy
| | - Renato Alberto Sinico
- Division of Nephrology, Section of Clinical Immunology, San Carlo Hospital, Milan, Italy
| | - Gabriella Moroni
- Division of Nephrology and Dialysis, Scientific Institute for Research and Health Care (IRCCS) Fondazione Ospedale Maggiore, Mangiagalli, Regina Elena, Milan, Italy
| | - Alice Bonanni
- Divisions of Nephrology, Dialysis, and Transplantation and
| | - Antonella Radice
- Division of Nephrology, Section of Clinical Immunology, San Carlo Hospital, Milan, Italy
| | - Angela Tincani
- Rheumatology and Clinical Immunology, Spedali Civili and University of Brescia, Brescia, Italy
| | - Federico Pratesi
- Clinical Immunology Unit, Department of Internal Medicine, University of Pisa, Pisa, Italy
| | - Paola Migliorini
- Clinical Immunology Unit, Department of Internal Medicine, University of Pisa, Pisa, Italy
| | - Corrado Murtas
- Divisions of Nephrology, Dialysis, and Transplantation and
| | - Franco Franceschini
- Rheumatology and Clinical Immunology, Spedali Civili and University of Brescia, Brescia, Italy
| | - Barbara Trezzi
- Division of Nephrology, Section of Clinical Immunology, San Carlo Hospital, Milan, Italy
| | - Francesca Brunini
- Division of Nephrology, Section of Clinical Immunology, San Carlo Hospital, Milan, Italy
| | - Rita Gatti
- Biomedical, Biotechnological and Translational Sciences and
| | - Regina Tardanico
- Service of Pathological Anatomy, Division of Nephrology, Spedali Civili di Brescia, Brescia, Italy
| | | | | | - Piergiorgio Messa
- Division of Nephrology and Dialysis, Scientific Institute for Research and Health Care (IRCCS) Fondazione Ospedale Maggiore, Mangiagalli, Regina Elena, Milan, Italy
| | - Pietro Ravani
- Division of Nephrology, University of Calgary, Calgary, Alberta, Canada; and
| | - Francesco Scolari
- Division of Nephrology, University of Brescia, Montichiari Hospital, Brescia, Italy
| | | | - Alberto Martini
- Paediatric Rheumatology, Scientific Institute for Research and Health Care (IRCCS), Istituto Giannina Gaslini, Genoa, Italy
| | | | - Gian Marco Ghiggeri
- Laboratory on Pathophysiology of Uremia and Divisions of Nephrology, Dialysis, and Transplantation and
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Orbai AM, Truedsson L, Sturfelt G, Nived O, Fang H, Alarcón GS, Gordon C, Merrill J, Fortin PR, Bruce IN, Isenberg DA, Wallace DJ, Ramsey-Goldman R, Bae SC, Hanly JG, Sanchez-Guerrero J, Clarke AE, Aranow CB, Manzi S, Urowitz MB, Gladman DD, Kalunian KC, Costner MI, Werth VP, Zoma A, Bernatsky S, Ruiz-Irastorza G, Khamashta MA, Jacobsen S, Buyon JP, Maddison P, Dooley MA, Van Vollenhoven RF, Ginzler E, Stoll T, Peschken C, Jorizzo JL, Callen JP, Lim SS, Fessler BJ, Inanc M, Kamen DL, Rahman A, Steinsson K, Franks AG, Sigler L, Hameed S, Pham N, Brey R, Weisman MH, McGwin G, Magder LS, Petri M. Anti-C1q antibodies in systemic lupus erythematosus. Lupus 2014; 24:42-9. [PMID: 25124676 DOI: 10.1177/0961203314547791] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Anti-C1q has been associated with systemic lupus erythematosus (SLE) and lupus nephritis in previous studies. We studied anti-C1q specificity for SLE (vs rheumatic disease controls) and the association with SLE manifestations in an international multicenter study. METHODS Information and blood samples were obtained in a cross-sectional study from patients with SLE (n = 308) and other rheumatologic diseases (n = 389) from 25 clinical sites (84% female, 68% Caucasian, 17% African descent, 8% Asian, 7% other). IgG anti-C1q against the collagen-like region was measured by ELISA. RESULTS Prevalence of anti-C1q was 28% (86/308) in patients with SLE and 13% (49/389) in controls (OR = 2.7, 95% CI: 1.8-4, p < 0.001). Anti-C1q was associated with proteinuria (OR = 3.0, 95% CI: 1.7-5.1, p < 0.001), red cell casts (OR = 2.6, 95% CI: 1.2-5.4, p = 0.015), anti-dsDNA (OR = 3.4, 95% CI: 1.9-6.1, p < 0.001) and anti-Smith (OR = 2.8, 95% CI: 1.5-5.0, p = 0.01). Anti-C1q was independently associated with renal involvement after adjustment for demographics, ANA, anti-dsDNA and low complement (OR = 2.3, 95% CI: 1.3-4.2, p < 0.01). Simultaneously positive anti-C1q, anti-dsDNA and low complement was strongly associated with renal involvement (OR = 14.9, 95% CI: 5.8-38.4, p < 0.01). CONCLUSIONS Anti-C1q was more common in patients with SLE and those of Asian race/ethnicity. We confirmed a significant association of anti-C1q with renal involvement, independent of demographics and other serologies. Anti-C1q in combination with anti-dsDNA and low complement was the strongest serological association with renal involvement. These data support the usefulness of anti-C1q in SLE, especially in lupus nephritis.
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Affiliation(s)
- A-M Orbai
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - L Truedsson
- Department of Laboratory Medicine, Section of Microbiology, Immunology and Glycobiology, Lund University, Lund, Sweden
| | - G Sturfelt
- Department of Rheumatology, Skåne University Hospital, Lund, Sweden
| | - O Nived
- Department of Rheumatology, Skåne University Hospital, Lund, Sweden
| | - H Fang
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - G S Alarcón
- Department of Medicine, Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - C Gordon
- Rheumatology Research Group, School of Immunity and Infection, College of Medical and Dental Sciences University of Birmingham, Birmingham, UK
| | - Jt Merrill
- Department of Clinical Pharmacology, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - P R Fortin
- Division of Rheumatology, Department of Medicine, Centre Hospitalier Universitaire (CHU) de Québec Axe Maladies Infectieuses et Immunitaires, CRCHU de Québec, Université Laval, Quebec City, Quebec, Canada
| | - I N Bruce
- Arthritis Research UK Centre for Epidemiology, Centre for Musculoskeletal Research, Institute of Inflammation and Repair, Manchester Academic Health Sciences Centre, The University of Manchester, Manchester, UK NIHR Manchester Musculoskeletal Biomedical Research Unit, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - D A Isenberg
- Centre for Rheumatology, Research Division of Medicine, London, UK
| | - D J Wallace
- Cedars-Sinai Medical Center, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - R Ramsey-Goldman
- Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - S-C Bae
- Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Korea
| | - J G Hanly
- Division of Rheumatology, Departments of Medicine and Pathology Capital Health and Dalhousie University, Halifax, Nova Scotia, Canada
| | - J Sanchez-Guerrero
- Mount Sinai Hospital and University Health Network, Toronto, Ontario, Canada
| | - A E Clarke
- Divisions of Clinical Epidemiology and Rheumatology, McGill University Health Centre, Montreal, Quebec, Canada
| | - C B Aranow
- Feinstein Institute for Medical Research, Manhasset, NY, USA
| | - S Manzi
- Department of Medicine, Division of Rheumatology, Allegheny Singer Research Institute, Allegheny General Hospital, Pittsburgh, PA, USA
| | - M B Urowitz
- Toronto Western Hospital Toronto, Ontario, Canada
| | - D D Gladman
- Toronto Western Hospital Toronto, Ontario, Canada
| | - K C Kalunian
- Division of Rheumatology, Allergy and Immunology, UCSD School of Medicine, La Jolla, CA, USA
| | - M I Costner
- North Dallas Dermatology Associates, Dallas, TX, USA
| | - V P Werth
- Philadelphia VA Medical Center and University of Pennsylvania, Philadelphia, PA, USA
| | - A Zoma
- Lanarkshire Centre for Rheumatology and Hairmyres Hospital, East Kilbride, UK
| | - S Bernatsky
- Divisions of Clinical Epidemiology and Rheumatology, McGill University Health Centre, Montreal, Quebec, Canada
| | - G Ruiz-Irastorza
- Autoimmune Diseases Research Unit, Hospital Universitario Cruces Universidad del Pais Vasco, Barakaldo, Spain
| | | | - S Jacobsen
- Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - J P Buyon
- New York University, New York, NY, USA
| | | | - M A Dooley
- University of North Carolina, Chapel Hill, NC, USA
| | | | - E Ginzler
- State University of New York, Downstate Medical Center, Brooklyn, NY, USA
| | - T Stoll
- Kantonsspital Schaffhausen, Schaffhausen, Switzerland
| | - C Peschken
- University of Manitoba Winnipeg, Manitoba, Canada
| | - J L Jorizzo
- Wake Forest University, Winston-Salem, NC, USA
| | - J P Callen
- University of Louisville, Louisville, KY, USA
| | - S S Lim
- Emory University, Atlanta, GA, USA
| | - B J Fessler
- Department of Medicine, Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - M Inanc
- Division of Rheumatology, Department of Internal Medicine, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey
| | - D L Kamen
- Medical University of South Carolina, Charleston, SC, USA
| | - A Rahman
- NIHR Manchester Musculoskeletal Biomedical Research Unit, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, UK
| | - K Steinsson
- Landspitali University Hospital, Reykjavik, Iceland
| | | | - L Sigler
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - S Hameed
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - N Pham
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - R Brey
- University of Texas Health Science Center, San Antonio, TX, USA
| | - M H Weisman
- Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - G McGwin
- Department of Medicine, Division of Clinical Immunology and Rheumatology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - L S Magder
- Department of Epidemiology and Public Health, University of Maryland, Baltimore, MD, USA
| | - M Petri
- Division of Rheumatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Abstract
Lupus nephritis is a serious potential feature of systemic lupus erythematous (SLE). Though SLE typically cycles through periods of flares and remission, patients often eventually succumb to end-stage kidney or cardiovascular damage. This review of the pathogenesis of lupus nephritis examines the role of the complement cascade; the significance of autoantibodies, the breaking of tolerance, and the implications of altered apoptosis in breaking tolerance; and the contributions of adaptive immunity and cross-talk with the innate immune system in driving renal damage. Delineation of basic mechanisms underlying the development of acute and chronic renal damage in lupus nephritis can result in the continued development of more specific and effective treatments.
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Affiliation(s)
- Rosalie M Sterner
- Department of Laboratory Medicine & Pathology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA ; Medical Scientist Training Program, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA
| | - Stella P Hartono
- Department of Laboratory Medicine & Pathology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA ; Medical Scientist Training Program, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA
| | - Joseph P Grande
- Department of Laboratory Medicine & Pathology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 USA
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Quan J, Lakhanpal A, Reddy MM, Zaman S, Li QZ, German DC, Olsen NJ, Kodadek T, Karp DR. Discovery of biomarkers for systemic lupus erythematosus using a library of synthetic autoantigen surrogates. J Immunol Methods 2013; 402:23-34. [PMID: 24269750 DOI: 10.1016/j.jim.2013.11.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/11/2013] [Accepted: 11/12/2013] [Indexed: 12/28/2022]
Abstract
Antibodies to a wide range of self-antigens, including those directed against nucleic acids or nucleic acid-binding proteins are the essential biomarkers for diseases such as systemic lupus erythematosus (SLE). Highly complex libraries of nonamers consisting of N-substituted glycines (peptoids) were screened for compounds that bound IgG from patients with SLE and earlier, incomplete autoimmune syndromes. Peptoids were identified that could identify subjects with SLE and related syndromes with a high sensitivity (70%) and specificity (97.5%). Immobilized peptoids were used to isolate IgG from both healthy subjects and SLE patients that reacted with known RNA-binding proteins. In the case of SLE patients, the peptoid-purified IgG reacted with several autoantigens, suggesting that the peptoids are capable of interacting with multiple, structurally similar molecules. These results show that the measurement of IgG binding to peptoids can identify subjects with high levels of pathogenic autoantibodies.
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Affiliation(s)
- Jiexia Quan
- Department of Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Immunology, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Akshai Lakhanpal
- Department of Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Immunology, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - M Muralidhar Reddy
- The Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458, USA; Opko Health, Inc., 555 Heritage Dr., Jupiter, FL 33458, USA
| | - Sayed Zaman
- Department of Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Immunology, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Quan-Zhen Li
- Department of Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Immunology, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Dwight C German
- Department of Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Immunology, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Nancy J Olsen
- The Department of Medicine, Penn State M.S. Hershey Medical Center, Hershey, PA 17033, USA
| | - Thomas Kodadek
- The Department of Chemistry, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - David R Karp
- Department of Medicine, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Immunology, UT Southwestern Medical Center, Dallas, TX 75390, USA; The Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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Mahler M, van Schaarenburg RA, Trouw LA. Anti-C1q autoantibodies, novel tests, and clinical consequences. Front Immunol 2013; 4:117. [PMID: 23717311 PMCID: PMC3653116 DOI: 10.3389/fimmu.2013.00117] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 04/30/2013] [Indexed: 02/02/2023] Open
Abstract
Although anti-C1q autoantibodies have been described more than four decades ago a constant stream of papers describing clinical associations or functional consequences highlights that anti-C1q antibodies are still hot and happening. By far the largest set of studies focus on anti-C1q antibodies is systemic lupus erythematosus (SLE). In SLE anti-C1q antibodies associate with involvement of lupus nephritis in such a way that in the absence of anti-C1q antibodies it is unlikely that a flare in nephritis will occur. Anti-C1q antibodies occur in several autoimmune conditions but also in healthy individuals. Although considerable progress has been made in the understanding of how anti-C1q antibodies may contribute to tissue injury there is still a lot to learn about the processes involved in the breaking of tolerance to this protein. There has been considerable improvement in the assays employed to test for the presence of anti-C1q antibodies. Hopefully with these new and standardized assays at hand larger clinical association studies will be conducted with independent replication. Such large-scale studies will reveal the true value of clinical testing for anti-C1q autoantibodies in several clinical conditions.
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Vanhecke D, Roumenina LT, Wan H, Osthoff M, Schaller M, Trendelenburg M. Identification of a major linear C1q epitope allows detection of systemic lupus erythematosus anti-C1q antibodies by a specific peptide-based enzyme-linked immunosorbent assay. ACTA ACUST UNITED AC 2013; 64:3706-14. [PMID: 22740328 DOI: 10.1002/art.34605] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Autoantibodies against C1q strongly correlate with the occurrence of severe nephritis in patients with systemic lupus erythematosus (SLE). We undertook this study to determine whether identification of the C1q epitope(s) recognized by these autoantibodies might lead to a better diagnostic assay and help elucidate the putative role of C1q and anti-C1q in SLE. METHODS SLE patient-derived anti-C1q Fab were used in a microarray-based peptide scan to identify the peptide sequence recognized by anti-C1q. Anti-C1q Fab binding to the target peptide was further analyzed using real-time interaction measurements (surface plasmon resonance) and peptide-based enzyme-linked immunosorbent assays (ELISAs). RESULTS A peptide scan of the collagen-like region of C1q identified 2 regions, 1 on the A chain and 1 on the B chain, that were the targets of the anti-C1q Fab. Binding was confirmed by surface plasmon resonance and showed nanomolar affinity. The A chain-derived peptide could specifically be detected in a peptide-based ELISA by SLE patient sera. Competition experiments suggested that this peptide represented one of the major linear epitopes of C1q that is the target of anti-C1q in SLE. Serum antibodies from most SLE patients but not from healthy individuals specifically bound to this epitope. Binding to the peptide correlated with binding of the same sera to native C1q but was found to be more sensitive for the detection of lupus nephritis. CONCLUSION We identified a major linear epitope of C1q that is the target of anti-C1q in SLE. The ELISA using this peptide was more specific and more sensitive than a conventional anti-C1q assay for the detection of active nephritis in SLE patients.
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Marks SD, Tullus K. Autoantibodies in systemic lupus erythematosus. Pediatr Nephrol 2012; 27:1855-68. [PMID: 22193636 DOI: 10.1007/s00467-011-2078-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 11/27/2011] [Accepted: 11/29/2011] [Indexed: 02/04/2023]
Abstract
Systemic lupus erythematosus (SLE) is a multifactorial disorder with multigenic inheritance and various environmental factors implicated in its aetiopathogenesis. Despite the multiple mechanisms involved in the aetiology of SLE being elusive, recent studies have made progress in our understanding of the pathogenic mechanisms via abnormal regulation of cell-mediated and humoral immunity that lead to tissue damage. The heterogeneity of the clinical manifestations probably reflects the complexity of the disease pathogenesis itself. The immune system in SLE is characterised by a complex interplay between overactive B cells, abnormally activated T cells and antigen-presenting cells. This interplay leads to the production of an array of inflammatory cytokines, apoptotic cells, diverse autoantibodies and immune complexes that in turn activate effector cells and the complement system, leading to tissue injury and damage which are the hallmarks of the clinical manifestations. SLE patients have dysregulation of inflammatory cytokines, chemokines and immune response-related genes, as well as of the genes involved in apoptosis, signal transduction and the cell cycle.
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Affiliation(s)
- Stephen D Marks
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children NHS Trust, Great Ormond Street, London, WC1N 3JH, UK.
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31
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Borchers AT, Leibushor N, Naguwa SM, Cheema GS, Shoenfeld Y, Gershwin ME. Lupus nephritis: a critical review. Autoimmun Rev 2012; 12:174-94. [PMID: 22982174 DOI: 10.1016/j.autrev.2012.08.018] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2012] [Indexed: 01/18/2023]
Abstract
Lupus nephritis remains one of the most severe manifestations of systemic lupus erythematosus associated with considerable morbidity and mortality. A better understanding of the pathogenesis of lupus nephritis is an important step in identifying more targeted and less toxic therapeutic approaches. Substantial research has helped define the pathogenetic mechanisms of renal manifestations and, in particular, the complex role of type I interferons is increasingly recognized; new insights have been gained into the contribution of immune complexes containing endogenous RNA and DNA in triggering the production of type I interferons by dendritic cells via activation of endosomal toll-like receptors. At the same time, there have been considerable advances in the treatment of lupus nephritis. Corticosteroids have long been the cornerstone of therapy, and the addition of cyclophosphamide has contributed to renal function preservation in patients with severe proliferative glomerulonephritis, though at the cost of serious adverse events. More recently, in an effort to minimize drug toxicity and achieve equal effectiveness, other immunosuppressive agents, including mycophenolate mofetil, have been introduced. Herein, we provide a detailed review of the trials that established the equivalency of these agents in the induction and/or maintenance therapy of lupus nephritis, culminating in the recent publication of new treatment guidelines by the American College of Rheumatology. Although newer biologics have been approved and continue to be a focus of research, they have, for the most part, been relatively disappointing compared to the effectiveness of biologics in other autoimmune diseases. Early diagnosis and treatment are essential for renal preservation.
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Affiliation(s)
- Andrea T Borchers
- Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis School of Medicine, Davis, CA 95616, United States
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32
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Stoyanova V, Tchorbadjieva M, Deliyska B, Vasilev V, Tsacheva I. Biochemical analysis of the epitope specificities of anti-C1q autoantibodies accompanying human lupus nephritis reveals them as a dynamic population in the course of the disease. Immunol Lett 2012; 148:69-76. [PMID: 22981967 DOI: 10.1016/j.imlet.2012.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 08/06/2012] [Accepted: 08/29/2012] [Indexed: 12/27/2022]
Abstract
We analyzed the epitope specificities of the polyclonal anti-C1q antibodies, present in human LN sera, searching to deduce the structural characteristics of C1q associated with its transition to an autoantigen. We screened 78 serum samples from LN patients distributed in three clinical groups - non-active, moderately active and severely active. We found three classes of C1q autoepitopes: (a) neo-epitopes, exposed upon immobilization due to conformational changes; (b) epitopes formed by sequences that are brought together by the conformation of the whole molecule; (c) cryptic epitopes that become exposed only after fragmentation of C1q. The latter suggest that the immunogen involved in the initiation of anti-C1q autoantibodies might be an extrinsic molecule that shares some degree of structural similarity to C1q. None of the tested epitope specificities was associated with active LN. We found a prevalence of anti-gC1q antibodies among the non-active LN patients suggesting that they might be the fraction of the polyclonal anti-C1q, preceding the initiation of autoimmunity to C1q, or alternatively, preceding LN flare.
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Affiliation(s)
- Vishnya Stoyanova
- Department of Biochemistry, Faculty of Biology, Sofia University, 8 Dragan Tsankov Str., 1164 Sofia, Bulgaria
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33
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Chen Z, Wang GS, Wang GH, Li XP. Anti-C1q antibody is a valuable biological marker for prediction of renal pathological characteristics in lupus nephritis. Clin Rheumatol 2012; 31:1323-9. [DOI: 10.1007/s10067-012-2017-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 05/09/2012] [Accepted: 05/29/2012] [Indexed: 11/29/2022]
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Radanova M, Vasilev V, Deliyska B, Kishore U, Ikonomov V, Ivanova D. Anti-C1q autoantibodies specific against the globular domain of the C1qB-chain from patient with lupus nephritis inhibit C1q binding to IgG and CRP. Immunobiology 2011; 217:684-91. [PMID: 22209113 DOI: 10.1016/j.imbio.2011.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 06/29/2011] [Accepted: 11/22/2011] [Indexed: 01/27/2023]
Abstract
Lupus nephritis is one of the most severe manifestations of systemic lupus erythematosus. Higher titers of serum anti-C1q autoantibodies correlate with disease activity in patients with lupus nephritis. Anti-C1q autoantibodies have been shown to bind neo-epitopes within the collagen region of human C1q. In a preliminary study, we recently reported that the anti-C1q autoantibodies could also recognize epitopes within the globular domain (gC1q) of the C1q molecule. Here, 38 sera from patients with renal biopsy-proven lupus nephritis were screened for the presence of anti-gC1q autoantibodies, using recombinant globular head regions of individual A (ghA), B (ghB) and C (ghC) chains of human C1q. We isolated anti-gC1q autoantibodies from three selected patients. Human C1q was pre-incubated with increasing concentrations of the isolated anti-ghA, anti-ghB or anti-ghC autoantibodies and its binding to different C1q target molecules such as IgG and CRP was then evaluated. Anti-ghB, but not anti-ghA and anti-ghC autoantibodies, markedly inhibited C1q interaction with IgG as well as CRP. These results appear to suggest that the anti-ghB autoantibodies may partially induce acquired functional C1q deficiency and thus may interfere with the biological function of C1q.
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Affiliation(s)
- Maria Radanova
- Department of Biochemistry, Molecular Medicine and Nutrigenomics, Medical University - Varna, Varna, Bulgaria.
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35
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O’Flynn J, Flierman R, van der Pol P, Rops A, Satchell SC, Mathieson PW, van Kooten C, van der Vlag J, Berden JH, Daha MR. Nucleosomes and C1q bound to glomerular endothelial cells serve as targets for autoantibodies and determine complement activation. Mol Immunol 2011; 49:75-83. [DOI: 10.1016/j.molimm.2011.07.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 07/26/2011] [Accepted: 07/27/2011] [Indexed: 12/31/2022]
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36
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Wu YL, Brookshire BP, Verani RR, Arnett FC, Yu CY. Clinical presentations and molecular basis of complement C1r deficiency in a male African-American patient with systemic lupus erythematosus. Lupus 2011; 20:1126-34. [PMID: 21784777 DOI: 10.1177/0961203311404914] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Homozygous deficiencies of early components for complement activation are among the strongest genetic risk factors for human systemic lupus erythematosus (SLE). Eleven cases of C1r deficiency are documented but this is the first report on the molecular basis of C1r deficiency. The proband is an African-American male who developed SLE at 3 months of age. He had a discoid lupus rash and diffuse proliferative glomerulonephritis. Serum complement analysis of the patient showed zero CH50 activity, undetectable C1r, and reduced levels of C1s, but highly elevated levels of complement C4, C2, and C1-inhibitor. The coding regions of the mutant C1R gene with 11 exons located at chromosome 12p13 were polymerase chain reaction (PCR)-amplified and sequenced to completion. DNA sequencing revealed a homozygous C→T mutation at nucleotide-6392 in exon 10 of the C1R gene, resulting in a nonsense mutation from Arg-380 (R380X). The patient's clinically normal mother was heterozygous for this mutation. A sequence-specific primer (SSP) PCR coupled with StuI-restriction fragment length polymorphism (RFLP) was developed to detect the novel mutation. Screening of 209 African-American SLE patients suggested that the R380X mutation is a rare causal variant. Mutations leading to early complement component deficiencies in SLE are mostly private variants with large effects.
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Affiliation(s)
- Y L Wu
- Center for Molecular and Human Genetics, Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
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Bigler C, Hopfer H, Danner D, Schaller M, Mihatsch MJ, Trendelenburg M. Anti-C1q autoantibodies do not correlate with the occurrence or severity of experimental lupus nephritis. Nephrol Dial Transplant 2010; 26:1220-8. [PMID: 20841491 DOI: 10.1093/ndt/gfq558] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND In systemic lupus erythematosus patients, a strong association between the occurrence of antibodies against complement C1q (anti-C1q) and lupus nephritis can be observed. However, the predictive value of anti-C1q titres for a renal flare remains to be determined. Increasing titres of anti-C1q before the occurrence of clinical apparent nephritis might not only serve as a clinical parameter but also indicate a direct pathogenic mechanism of anti-C1q. METHODS The aim of this study was to analyse the occurrence of anti-C1q before the onset of experimental lupus nephritis in MRL/MpJ +/+ mice and to correlate anti-C1q titres with the type and severity of glomerulonephritis (GN) developing at advanced age. RESULTS As judged by a number of morphological and immunological analyses, GN in MRL/MpJ +/+ mice resembled human lupus nephritis and occurred in variable degrees of severity. We also observed an abundant and early presence of anti-C1q. However, anti-C1q neither correlated with overall survival nor with any histological marker of severity of GN. CONCLUSIONS The absence of a correlation between the presence of anti-C1q and the occurrence of experimental lupus nephritis contradicts the hypothesis that anti-C1q are pathogenic. However, different pathogenic mechanisms of experimental lupus nephritis and human proliferative lupus nephritis cannot be excluded.
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Affiliation(s)
- Cornelia Bigler
- Clinical Immunology, Department of Biomedicine, University Hospital Basel, Switzerland
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Cai X, Yang X, Lian F, Lin X, Liang M, Li J, Chen X, Liang L, Qin S, Fu J. Correlation between serum anti-C1q antibody levels and renal pathological characteristics and prognostic significance of anti-C1q antibody in lupus nephritis. J Rheumatol 2010; 37:759-65. [PMID: 20194446 DOI: 10.3899/jrheum.090779] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To investigate the relationship between serum anti-C1q antibody levels and renal pathological characteristics in lupus nephritis as well as the prognostic significance of serum anti-C1q antibody. METHODS Seventy-three patients with biopsy-proven lupus nephritis were enrolled. Anti-C1q antibody was measured in serum samples taken within 7 days before renal biopsy and remeasured at the end of the first and the third month after treatment. All patients were followed at least once a month for 3 months. A cross-sectional study analyzed the relationship between serum anti-C1q antibody levels and renal histopathology and nephritic activity, while a longitudinal study evaluated the prognostic significance of anti-C1q antibody levels in lupus nephritis. RESULTS Fifty-eight of 73 patients (79.5%) were reported as having positive baseline serum anti-C1q antibody, with a mean level of 95.3 (+/- 55.2) U/ml. Significant differences were found in serum anti-C1q antibody levels between each World Health Organization (WHO) classification of lupus nephritis. The serum anti-C1q antibody level of WHO class IV was the highest. Serum anti-C1q antibody was positively correlated with the active and chronic indices in renal pathology. Patients with persistent high levels or increased titers of serum anti-C1q antibody tended to develop delayed remission in nephropathy. Serum anti-C1q antibody levels before and after treatment were relevant to renal remission, but serum anti-C1q antibody at the end of the third month after treatment was a stronger predictor for the prognosis after adjustment in the Cox's proportional hazards regression model. CONCLUSION Serum anti-C1q antibody is a valuable noninvasive biological marker for evaluation of renal involvement and lupus prognosis.
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Affiliation(s)
- Xiaoyan Cai
- Department of Rheumatology and Clinical Immunology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
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Tsirogianni A, Pipi E, Soufleros K. Relevance of anti-C1q autoantibodies to lupus nephritis. Ann N Y Acad Sci 2009; 1173:243-51. [PMID: 19758158 DOI: 10.1111/j.1749-6632.2009.04750.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The first component of the classical pathway of the complement system (C1q) is considered to have a crucial role in the clearance of immune complexes (ICs) as well as in the removal of waste material originating from apoptotic cells. A prolonged exposure of C1q epitopes to the immune system could eventually lead to an autoimmune response against itself. Although autoantibodies against C1q are found in several diseases, their clinical interest originates from their strong association to active lupus nephritis (LN). Several studies indicate that anti-C1q autoantibodies could serve as a reliable serologic marker in the assessment of LN activity compared to other immunological tests. Additionally, it was suggested that anti-C1q autoantibodies could play a role in LN pathogenesis. Their potential pathogenic actions likely depend on genetic background, titers, Ig classes and subclasses, and specific epitopes of anti-C1q autoantibodies as well as C1q availability and allocation. It is still unclear which different types of anti-C1q autoantibodies dominate in each case and if their upregulation is pathogenic, an epiphenomenon of aberrant tissue damage, or compensatory to an uncontrolled immune response.
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Affiliation(s)
- Alexandra Tsirogianni
- Department of Immunology-Histocompatibility, Evangelismos General Hospital, Athens, Greece.
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Sinico RA, Rimoldi L, Radice A, Bianchi L, Gallelli B, Moroni G. Anti-C1q autoantibodies in lupus nephritis. Ann N Y Acad Sci 2009; 1173:47-51. [PMID: 19758131 DOI: 10.1111/j.1749-6632.2009.04746.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Anti-C1q antibodies are found in a variety of diseases, in addition to systemic lupus erythematosus (SLE), and in 3-5% of normal individuals. In particular, anti-C1q antibodies are detected at a high titer in 100% of patients with hypocomplementemic urticarial vasculitis and in 30-48% of SLE patients. Their titer correlates with active renal disease with a sensitivity of 44-100% and a specificity of 70-92%. An increase in anti-C1q antibody titer has been suggested to be able to predict renal flares in lupus nephritis so that monitoring anti-C1q might be valuable for the clinical management of SLE patients as a noninvasive biological marker. Recently our group studied 228 patients affected by lupus nephritis and found that the association of anti-C1q, C3, and C4, in a multivariate analysis, provided the best prediction of renal flares, particularly in patients with focal and diffuse proliferative lupus nephritis and in the absence of antiphospholipid antibodies.
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Affiliation(s)
- Renato Alberto Sinico
- Clinical Immunology Unit, Azienda Ospedaliera, Ospedale San Carlo Borromeo, Milano, Italy.
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Abstract
The predominance of renal involvement in autoimmune diseases can most likely be assigned to the specialised function of the kidneys filtrating over 120 ml plasma per minute. Complement activation by autoantibodies directed against planted antigens or antigens already present in renal tissue in the subendothelial and mesangial regions provoke an inflammatory response ultimately resulting in renal damage. New data also suggest complement involvement in the pathogenesis of renal disease caused by subepithelial immune complex deposition. On the other hand complement itself can also be a target of an autoimmune responses causing renal damage as seen in SLE. The results on intervention of complement activation in clinical practise are awaited.
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Affiliation(s)
- M A Seelen
- Renal Transplantation Unit, Department of Internal Medicine, University Medical Center, Groningen, The Netherlands
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Potlukova E, Kralikova P. Complement component c1q and anti-c1q antibodies in theory and in clinical practice. Scand J Immunol 2008; 67:423-30. [PMID: 18363591 DOI: 10.1111/j.1365-3083.2008.02089.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The complement system is a major part of the innate immunity. The first component of the classical pathway of complement activation, C1q, plays a crucial role in the clearance of immune complexes and apoptotic bodies from the organism. Autoantibodies against C1q (anti-C1q) have been found in a number of autoimmune and infectious diseases. They have been best described in patients with systemic lupus erythematosus, where they are thought to play a pathogenic role in lupus nephritis (LN). Their high negative predictive value for the occurrence of active proliferative LN, as well as their possible ability to indicate a renal flare as soon as 6 months in advance, have rendered anti-C1q antibodies a novel non-invasive tool in the detection of active LN.
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Affiliation(s)
- E Potlukova
- Third Clinic of Medicine, General Teaching Hospital, First Faculty of Medicine, Charles University, Prague, Czech Republic.
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Jaekell HP, Trabandt A, Grobe N, Werle E. Anti-dsDNA antibody subtypes and anti-C1q antibodies: toward a more reliable diagnosis and monitoring of systemic lupus erythematosus and lupus nephritis. Lupus 2007; 15:335-45. [PMID: 16830879 DOI: 10.1191/0961203306lu2308oa] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The putative distinct diagnostic and pathogenic potential of aDNA-Ab subtypes, differing in their affinity or epitope specificity, was subject of several studies with controversial results. Comparing five assays, characterized by different reaction conditions and nature/source of dsDNA, we investigated the abovementioned problem in a retrospective study on 100 systemic lupus erythematosus (SLE) patients and 100 controls (other CTD, autoimmune hepatopathies). As demonstrated, only assay 3 (Farrzyme, TBS, UK) and 5 (Farr-RIA, Trinity Biotech, Ireland) are really suitable to detect primarily high avidity aDNA-Ab. Both were significantly linked to lupus nephritis (specificity 84%) and highly specific for SLE (95 and 96%). Thereby, assay 3 was found to be the first solid phase ELISA probably suitable to replace the Farr-RIA. Classical ELISAs (assay 1, Orgentec, Germany, and 2, Bindazyme, TBS, UK), detecting aDNA-Ab more or less independent from their avidity, or tests with only intermediate specificity for high avidity Ab (assay 4, ELIAdn, Sweden Diagnostics, Germany), were less specific for SLE (83, 79, 91%, respectively) and not associated with renal involvement (specificity 54-57%). At least in the patients studied here, obvious antigen-related differences could not be observed. With slight differences, all assays were suitable to monitor disease activity and therapy in SLE, agreeing with the ECLAM score in about 70-80% of cases. For lupus nephritis, aC1q-Ab are as specific as high avidity aDNA-Ab and capable to close a diagnostic gap in some cases. Thus, to enhance the specificity (up to 98%) and to consider the distinct diagnostic/pathogenic potential of aDNA-Ab subtypes in SLE, under routine clinical laboratory conditions it should be recommended to combine a sensitive screening test with a more specific second assay.
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Affiliation(s)
- H P Jaekell
- Institute of Laboratory Diagnostics, Microbiology and Transfusion Medicine, Dietrich Bonhoeffer Clinical Centre, Neubrandenburg, Germany.
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Abstract
Complement is involved in the pathogenesis of systemic lupus erythematosus (SLE) in multiple ways and may act as both friend and foe. Inherited homozygous deficiency of one of the earliest components of the classical pathway is strongly associated with susceptibility to the development of SLE. However, complement is also implicated in the effector inflammatory phase of the autoimmune response that characterizes the disease. A further paradox in the links between complement and SLE is the observation that autoantibodies to some complement proteins, especially to C1q, develop as part of the autoantibody response. In this chapter, the role of the complement system in SLE is reviewed and hypotheses advanced to explain the complex relationships between complement and lupus.
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Affiliation(s)
- M J Lewis
- Division of Medicine, Faculty of Medicine, Rheumatology Section, Imperial College, Hammersmith Campus, Du Cane Road, London, W12 0NN, UK
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Abstract
PURPOSE OF REVIEW It is well recognized that the complement system plays multiple roles in systemic lupus erythematosus. Activation of the classical pathway by immune complexes leads to the generation of inflammatory mediators, thus promoting tissue injury. Complement activation also plays an important role in the maintenance of tolerance to self-antigens. This review discusses recent insights in the role of complement in the pathogenesis of systemic lupus erythematosus. RECENT FINDINGS The antiphospholipid syndrome is a major feature of systemic lupus erythematosus. New findings have clearly demonstrated that the prothrombotic effects seen in a mouse model of this syndrome depend on complement activation, whereas the protective effects of heparin are due to its anticomplementary effects rather than its anticoagulant action. Secondly, a potential mechanism explaining the association of anti-C1q autoantibodies with lupus glomerulonephritis has been elucidated in a mouse model system. SUMMARY New findings have helped to reinforce the role of complement in the etiology and tissue damage of systemic lupus erythematosus. These findings point to more precise, mechanism-based therapies for autoimmune and inflammatory disease.
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Affiliation(s)
- David R Karp
- Rheumatic Diseases Division, The University of Texas Southwestern Medical Center at Dallas, 75390, USA.
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Trendelenburg M. Antibodies against C1q in patients with systemic lupus erythematosus. ACTA ACUST UNITED AC 2005; 27:276-85. [PMID: 16189648 DOI: 10.1007/s00281-005-0007-y] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Accepted: 05/19/2005] [Indexed: 10/25/2022]
Abstract
The first component of the classical pathway of complement (C1q) is considered to be involved in the pathogenesis of systemic lupus erythematosus (SLE). This view is based on the observation that a substantial number of patients with SLE develop hypocomplementemia with depletion of the classical pathway components, and C1q has been shown to play an important role in the clearance of immune complexes and apoptotic bodies. In addition, homozygous C1q deficiency is the strongest disease susceptibility gene for the development of SLE that has been characterised in humans. However, most SLE patients have no primary complement deficiency. Hypocomplementemia in SLE patients is a secondary event and often associated with antibodies against C1q (anti-C1q). Although anti-C1q have been found in a number of distinct autoimmune disorders, they are best described in patients with SLE where they strongly correlate with renal flares. Current data suggest that the occurrence of anti-C1q in SLE patients is necessary but not sufficient for the development of proliferative lupus nephritis, suggesting an interference with the normal function of the complement system.
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Affiliation(s)
- Marten Trendelenburg
- Medical Clinic B, University Hospital Basel, Petersgraben 4, Basel 4031, Switzerland.
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Abstract
PURPOSE OF REVIEW Despite decades of extensive work in the understanding of the etiopathogenesis of systemic lupus erythematosus, few biomarkers have been validated and widely accepted for this disease. The lack of reliable, specific biomarkers not only hampers clinical management of systemic lupus erythematosus but also impedes development of new therapeutic agents. This paper reviews briefly the historical aspects of systemic lupus erythematosus biomarkers and summarizes recent studies on candidate biomarkers. RECENT FINDINGS Recognizing the urgent need for lupus biomarkers, a Lupus Biomarker Working Group has recently been initiated to facilitate collaborative efforts aimed at identifying and validating biomarkers for systemic lupus erythematosus. Based on available data, several laboratory markers have shown promise as biomarkers for susceptibility, diagnosis, and disease activity. These include Fc receptor genes (disease susceptibility), complement C4d-bound erythrocytes (diagnosis or disease activity), CD27 plasma cells (disease activity), 'interferon signature' (disease activity), and anti-C1q antibodies (disease activity and organ involvement). SUMMARY There is a longstanding and recently rejuvenated enthusiasm for biomarkers that precisely and specifically reflect the pathophysiologic and clinical changes in systemic lupus erythematosus. Promising candidate biomarkers have been identified but must still be validated through rigorous, large-scale multicenter studies.
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Affiliation(s)
- Chau-Ching Liu
- Lupus Center of Excellence, School of Health Sciences, University of Pittsburgh, PA 15261, USA
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Sinico RA, Radice A, Ikehata M, Giammarresi G, Corace C, Arrigo G, Bollini B, Li Vecchi M. Anti-C1q Autoantibodies in Lupus Nephritis: Prevalence and Clinical Significance. Ann N Y Acad Sci 2005; 1050:193-200. [PMID: 16014534 DOI: 10.1196/annals.1313.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recently, anti-C1q autoantibodies have been proposed as a useful marker in systemic lupus erythematosus (SLE) since their occurrence correlates with renal involvement and, possibly, with nephritic activity. We aimed to evaluate the prevalence of anti-C1q antibodies in patients with SLE, with and without renal involvement, and to correlate these markers' presence and levels with the activity of the disease and nephropathy. We studied 61 patients with SLE, 40 of whom had biopsy-proven lupus nephritis; 35 patients with other connective tissue diseases; and 54 healthy controls. In addition, 18 lupus nephritis patients were followed up during the disease time course. Anti-C1q antibodies were measured using "homemade" ELISA with high salt concentration (1 M sodium chloride). High anti-C1q antibody titers (> 55 AU) were present in 27 of 61 (44%) SLE patients and in 4% and 0% of normal blood donors and pathologic controls, respectively. Anti-C1q antibodies were found in 60% of patients with lupus nephritis compared with only 14% of SLE patients without nephropathy (P < 0.05). Moreover, patients who were positive for anti-C1q antibodies had a higher European Consensus Lupus Activity Measurement (ECLAM) score (4.35 vs. 2.2); 89% of patients with active lupus nephritis showed high titers of anti-C1q antibodies compared with 0% of patients with inactive nephritis. Anti-C1q and anti-dsDNA antibodies agreed in 79% of cases. Our results confirm that anti-C1q antibodies are present in a significant percentage of SLE patients, and that their presence and levels correlate with disease activity-in particular, during renal flare-ups.
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Affiliation(s)
- Renato Alberto Sinico
- Dipartimento di Nefrologia e Immunologia, Azienda Ospedaliera, Ospedale San Carlo Borromeo, Via Pio Secondo 3, 20153 Milano, Italy.
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