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Coss SL, Zhou D, Chua GT, Aziz RA, Hoffman RP, Wu YL, Ardoin SP, Atkinson JP, Yu CY. The complement system and human autoimmune diseases. J Autoimmun 2023; 137:102979. [PMID: 36535812 PMCID: PMC10276174 DOI: 10.1016/j.jaut.2022.102979] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022]
Abstract
Genetic deficiencies of early components of the classical complement activation pathway (especially C1q, r, s, and C4) are the strongest monogenic causal factors for the prototypic autoimmune disease systemic lupus erythematosus (SLE), but their prevalence is extremely rare. In contrast, isotype genetic deficiency of C4A and acquired deficiency of C1q by autoantibodies are frequent among patients with SLE. Here we review the genetic basis of complement deficiencies in autoimmune disease, discuss the complex genetic diversity seen in complement C4 and its association with autoimmune disease, provide guidance as to when clinicians should suspect and test for complement deficiencies, and outline the current understanding of the mechanisms relating complement deficiencies to autoimmunity. We focus primarily on SLE, as the role of complement in SLE is well-established, but will also discuss other informative diseases such as inflammatory arthritis and myositis.
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Affiliation(s)
- Samantha L Coss
- Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University, Columbus, OH, USA.
| | - Danlei Zhou
- Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Gilbert T Chua
- Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Rabheh Abdul Aziz
- Department of Pediatrics, The Ohio State University, Columbus, OH, USA; Department of Allergy, Immunology and Rheumatology, University of Buffalo, NY, USA
| | - Robert P Hoffman
- Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Yee Ling Wu
- Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University, Columbus, OH, USA; Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, USA
| | - Stacy P Ardoin
- Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University, Columbus, OH, USA
| | - John P Atkinson
- Department of Medicine, Division of Rheumatology, Washington University School of Medicine, St Louis, MO, USA
| | - Chack-Yung Yu
- Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University, Columbus, OH, USA.
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2
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Wang L, Yang Z, Yu H, Lin W, Wu R, Yang H, Yang K. Predicting diagnostic gene expression profiles associated with immune infiltration in patients with lupus nephritis. Front Immunol 2022; 13:839197. [PMID: 36532018 PMCID: PMC9755505 DOI: 10.3389/fimmu.2022.839197] [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: 12/19/2021] [Accepted: 11/09/2022] [Indexed: 12/03/2022] Open
Abstract
Objective To identify potential diagnostic markers of lupus nephritis (LN) based on bioinformatics and machine learning and to explore the significance of immune cell infiltration in this pathology. Methods Seven LN gene expression datasets were downloaded from the GEO database, and the larger sample size was used as the training group to obtain differential genes (DEGs) between LN and healthy controls, and to perform gene function, disease ontology (DO), and gene set enrichment analyses (GSEA). Two machine learning algorithms, least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature elimination (SVM-RFE), were applied to identify candidate biomarkers. The diagnostic value of LN diagnostic gene biomarkers was further evaluated in the area under the ROC curve observed in the validation dataset. CIBERSORT was used to analyze 22 immune cell fractions from LN patients and to analyze their correlation with diagnostic markers. Results Thirty and twenty-one DEGs were screened in kidney tissue and peripheral blood, respectively. Both of which covered macrophages and interferons. The disease enrichment analysis of DEGs in kidney tissues showed that they were mainly involved in immune and renal diseases, and in peripheral blood it was mainly enriched in cardiovascular system, bone marrow, and oral cavity. The machine learning algorithm combined with external dataset validation revealed that C1QA(AUC = 0.741), C1QB(AUC = 0.758), MX1(AUC = 0.865), RORC(AUC = 0.911), CD177(AUC = 0.855), DEFA4(AUC= 0.843)and HERC5(AUC = 0.880) had high diagnostic value and could be used as diagnostic biomarkers of LN. Compared to controls, pathways such as cell adhesion molecule cam, and systemic lupus erythematosus were activated in kidney tissues; cell cycle, cytoplasmic DNA sensing pathways, NOD-like receptor signaling pathways, proteasome, and RIG-1-like receptors were activated in peripheral blood. Immune cell infiltration analysis showed that diagnostic markers in kidney tissue were associated with T cells CD8 and Dendritic cells resting, and in blood were associated with T cells CD4 memory resting, suggesting that CD4 T cells, CD8 T cells and dendritic cells are closely related to the development and progression of LN. Conclusion C1QA, C1QB, MX1, RORC, CD177, DEFA4 and HERC5 could be used as new candidate molecular markers for LN. It may provide new insights into the diagnosis and molecular treatment of LN in the future.
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Affiliation(s)
- Lin Wang
- Nephrology Department, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Zhihua Yang
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, China
- Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Hangxing Yu
- Nephrology Department, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Wei Lin
- Nephrology Department, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Ruoxi Wu
- Nephrology Department, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Hongtao Yang
- Nephrology Department, First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Kang Yang
- Nephrology Department, The First Affiliated Hospital of Henan University of Chinese Medicine, Henan, China
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3
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Overview on the role of complement-specific autoantibodies in diseases. Mol Immunol 2022; 151:52-60. [PMID: 36084516 DOI: 10.1016/j.molimm.2022.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 08/03/2022] [Accepted: 08/15/2022] [Indexed: 11/24/2022]
Abstract
The complement system is recognized as a major pathogenic or contributing factor in an ever-growing number of diseases. In addition to inherited factors, autoantibodies to complement proteins have been detected in various systemic and organ-specific disorders. These include antibodies directed against complement components, regulators and receptors, but also protein complexes such as autoantibodies against complement convertases. In some cases, the autoantibodies are relatively well characterized and a pathogenic role is incurred and their detection has diagnostic value. In other cases, the relevance of the autoantibodies is rather unclear. This review summarizes what we know of complement specific autoantibodies in diseases and identifies unresolved questions regarding their functional effect and relevance.
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Autoantibodies against Complement Classical Pathway Components C1q, C1r, C1s and C1-Inh in Patients with Lupus Nephritis. Int J Mol Sci 2022; 23:ijms23169281. [PMID: 36012546 PMCID: PMC9409282 DOI: 10.3390/ijms23169281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/12/2022] [Accepted: 08/16/2022] [Indexed: 01/27/2023] Open
Abstract
Autoantibodies against the complement component C1q (anti-C1q) are among the main biomarkers in lupus nephritis (LN) known to contribute to renal injury. C1q, the recognition subcomponent of the complement classical pathway, forms a heterotetrameric complex with C1r and C1s, and can also associate a central complement regulator and C1 Inhibitor (C1-Inh). However, the frequency and the pathogenic relevance of anti-C1r, anti-C1s and anti-C1-Inh autoantibodies remain poorly studied in LN. In this paper, we screened for anti-C1q, anti-C1r, anti-C1s and anti-C1-Inh autoantibodies and evaluated their association with disease activity and severity in 74 LN patients followed up for 5 years with a total of 266 plasma samples collected. The presence of anti-C1q, anti-C1r, anti-C1s and anti-C1-Inh was assessed by ELISA. IgG was purified by Protein G from antigen-positive plasma and their binding to purified C1q, C1r and C1s was examined by surface plasmon resonance (SPR). The abilities of anti-C1q, anti-C1r and anti-C1s binding IgG on C1 complex formation were analyzed by ELISA. The screening of LN patients’ plasma revealed 14.9% anti-C1q positivity; only 4.2%, 6.9% and 0% were found to be positive for anti-C1r, anti-C1s and anti-C1-Inh, respectively. Significant correlations were found between anti-C1q and anti-dsDNA, and anti-nuclear antibodies, C3 and C4, respectively. High levels of anti-C1q antibodies were significantly associated with renal histologic lesions and correlated with histological activity index. Patients with the most severe disease (A class according to BILAG Renal score) had higher levels of anti-C1q antibodies. Anti-C1r and anti-C1s antibodies did not correlate with the clinical characteristics of the LN patients, did not interfere with the C1 complex formation, and were not measurable via SPR. In conclusion, the presence of anti-C1q, but not anti-C1s or anti-C1r, autoantibodies contribute to the autoimmune pathology and the severity of LN.
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5
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Omidi F, Khoshmirsafa M, Kianmehr N, Faraji F, Delbandi A, Seif F, Shekarabi M. Comparison of circulating miR-148a and miR-126 with autoantibodies as biomarkers of lupus nephritis in patients with SLE. J Immunoassay Immunochem 2022; 43:634-647. [PMID: 35938736 DOI: 10.1080/15321819.2022.2099225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Lupus nephritis (LN) is the main manifestation of systemic Lupus Erythematosus (SLE). MicroRNAs (miRNAs) and autoantibodies could be suitable candidate biomarkers of LN. This study evaluates the expression of circulating miR-148a and miR-126 along with anti-dsDNA, anti-C1q, and anti-C3b autoantibodies in SLE patients with LN (SLE + LN). 30 women with SLE, 30 women with SLE + LN, and 25 women as healthy controls (HCs) were enrolled in this study. The plasma expression of selected miRNAs was evaluated by real-time PCR. The serum level of anti-dsDNA, C1q, and C3b antibodies was measured by the ELISA. The expression of miR-148a was significantly increased in SLE and SLE+LN groups compared with the control group. No significant difference was found in the expression of miR-126 among the groups. The frequency of autoantibodies was significantly higher in the SLE + LN group than SLE. The Higher levels of circulating miR-148a in the SLE samples compared with the HCs suggest that this miRNA could be a reliable biomarker for SLE patients (with or without LN). Also, autoantibodies against dsDNA, C1q, and, C3 could be used for the prediction of SLE nephritis, independently. However, further studies are needed to confirm these findings.
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Affiliation(s)
- Frouzan Omidi
- Immunology Research Center, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran.,Immunology Department, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Khoshmirsafa
- Immunology Research Center, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran.,Immunology Department, Iran University of Medical Sciences, Tehran, Iran
| | - Nahid Kianmehr
- Rheumatology, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Faraji
- Immunology Research Center, Institute of Immunology and Infectious Diseases, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Delbandi
- Immunology Department, Iran University of Medical Sciences, Tehran, Iran
| | - Farhad Seif
- Immunology, Academic Center for Education Culture and Research, Tehran, Iran
| | - Mehdi Shekarabi
- Immunology Department, Iran University of Medical Sciences, Tehran, Iran
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6
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Anti-Idiotype scFv Localizes an Autoepitope in the Globular Domain of C1q. Int J Mol Sci 2021; 22:ijms22158288. [PMID: 34361054 PMCID: PMC8347764 DOI: 10.3390/ijms22158288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/29/2021] [Accepted: 07/29/2021] [Indexed: 11/16/2022] Open
Abstract
We addressed the issue of C1q autoantigenicity by studying the structural features of the autoepitopes recognized by the polyclonal anti-C1q antibodies present in Lupus Nephritis (LN) sera. We used six fractions of anti-C1q as antigens and selected anti-idiotypic scFv antibodies from the phage library "Griffin.1". The monoclonal scFv A1 was the most potent inhibitor of the recognition of C1q and its fragments ghA, ghB and ghC, comprising the globular domain gC1q, by the lupus autoantibodies. It was sequenced and in silico folded by molecular dynamics into a 3D structure. The generated 3D model of A1 elucidated CDR similarity to the apical region of gC1q, thus mapping indirectly for the first time a globular autoepitope of C1q. The VH CDR2 of A1 mimicked the ghA sequence GSEAD suggested as a cross-epitope between anti-DNA and anti-C1q antibodies. Other potential inhibitors of the recognition of C1q by the LN autoantibodies among the selected recombinant antibodies were the monoclonal scFv F6, F9 and A12.
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7
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Willrich MAV, Braun KMP, Moyer AM, Jeffrey DH, Frazer-Abel A. Complement testing in the clinical laboratory. Crit Rev Clin Lab Sci 2021; 58:447-478. [PMID: 33962553 DOI: 10.1080/10408363.2021.1907297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The complement system is the human's first line of defense against microbial pathogens because of its important housekeeping and infection/inflammation roles. It is composed of a series of soluble and cell-bound proteins that are activated in a cascade effect, similar to the coagulation pathways. There are different pattern recognizing molecules that activate the complement system in response to stimuli or threats, acting through three initiation pathways: classical, lectin, and alternative. All three activation pathways converge at the C3 component and share the terminal pathway. The main outputs of the complement system action are lytic killing of microbes, the release of pro-inflammatory anaphylatoxins, and opsonization of targets. Laboratory testing is relevant in the setting of suspected complement deficiencies, as well as in the emerging number of diseases related to dysregulation (over-activation) of complement. Most common assays measure complement lytic activity and the different complement component concentrations. Specialized testing includes the evaluation of autoantibodies against complement components, activation fragments, and genetic studies. In this review, we cover laboratory testing for complement and the conditions with complement involvement, as well as current challenges in the field.
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Affiliation(s)
| | - Karin M P Braun
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Ann M Moyer
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - David H Jeffrey
- Exsera Biolabs, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ashley Frazer-Abel
- Exsera Biolabs, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
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8
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Kianmehr N, Khoshmirsafa M, Shekarabi M, Falak R, Haghighi A, Masoodian M, Seif F, Omidi F, Shirani F, Dadfar N. High frequency of concurrent anti-C1q and anti-dsDNA but not anti-C3b antibodies in patients with Lupus Nephritis. J Immunoassay Immunochem 2021; 42:406-423. [PMID: 33788670 DOI: 10.1080/15321819.2021.1895215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Lupus Nephritis (LN) in patients with Systemic Lupus Erythematosus (SLE) is one of the most serious and prevalent manifestations. The procedure of renal biopsy is harmful and accompanied by potential hazards. Therefore, introducing reliable biomarkers to predict LN is exceedingly worthwhile. In the present study, we compared the diagnostic values of circulating autoantibodies against dsDNA, C1q, C3b, SSA, SSB, and Sm alone or in combination to predict LN. This study evaluated the abovementioned autoantibodies in 40 healthy controls (HCs) and 95 SLE patients with different kidney involvements, including absent (n = 40), inactive (n = 20), and active (n = 35) LN using EIA method. The frequency and odds ratio of anti-dsDNA (71.4%, OR = 4.2), anti-C1q (62.9%, OR = 5.1), and the simultaneous existence of anti-C1q and anti-dsDNA (51.4%, OR = 6) antibodies were significantly higher in the active LN group compared with both inactive and absent LN groups. Moreover, the levels of anti-C1q and anti-dsDNA antibodies positively correlated with disease activity in patients with SLE. The prevalence of these autoantibodies was associated with the severity of LN biopsies. These data suggest that anti-C1q and anti-dsDNA antibodies and also their simultaneous presence may be valuable diagnostic biomarkers for LN prediction in patients with SLE.
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Affiliation(s)
- Nahid Kianmehr
- Department of Rheumatology, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Khoshmirsafa
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.,Immunology Research Center, Institute of Immunology and Infectious Diseases Iran University of Medical Sciences, Tehran, Iran
| | - Mehdi Shekarabi
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.,Immunology Research Center, Institute of Immunology and Infectious Diseases Iran University of Medical Sciences, Tehran, Iran
| | - Reza Falak
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.,Immunology Research Center, Institute of Immunology and Infectious Diseases Iran University of Medical Sciences, Tehran, Iran
| | - Anousheh Haghighi
- Department of Rheumatology, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Masoodian
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Farhad Seif
- Academic Center for Education, Culture and Research, Tehran, Iran
| | - Forouzan Omidi
- Department of Immunology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Shirani
- Department of Rheumatology, Iran University of Medical Sciences, Tehran, Iran
| | - Nima Dadfar
- Department of Rheumatology, Iran University of Medical Sciences, Tehran, Iran
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Galindo-Izquierdo M, Pablos Alvarez JL. Complement as a Therapeutic Target in Systemic Autoimmune Diseases. Cells 2021; 10:cells10010148. [PMID: 33451011 PMCID: PMC7828564 DOI: 10.3390/cells10010148] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/06/2021] [Accepted: 01/08/2021] [Indexed: 12/16/2022] Open
Abstract
The complement system (CS) includes more than 50 proteins and its main function is to recognize and protect against foreign or damaged molecular components. Other homeostatic functions of CS are the elimination of apoptotic debris, neurological development, and the control of adaptive immune responses. Pathological activation plays prominent roles in the pathogenesis of most autoimmune diseases such as systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, dermatomyositis, and ANCA-associated vasculitis. In this review, we will review the main rheumatologic autoimmune processes in which complement plays a pathogenic role and its potential relevance as a therapeutic target.
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10
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Ohtani K. Complement-Related Proteins and Their Measurements: The Current Status of Clinical Investigation. Nephron Clin Pract 2020; 144 Suppl 1:7-12. [PMID: 33232963 DOI: 10.1159/000512494] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 10/21/2020] [Indexed: 11/19/2022] Open
Abstract
Complement has been considered to be a factor that protects the host against invading microorganisms during infection. However, in recent years, complement-related protein deficiency has been found to be involved in the onset of various diseases, such as autoimmune and inflammatory diseases. In Japan, C3, C4, and CH50 tests were generally performed only when a complement system examination was necessary and there were not enough examinations for other complement factors. Since the complement system has a very complicated activation pathway, at present, it is not well known which molecule must be measured to understand the pathological condition or pathogenesis in complement-related diseases. Furthermore, since the frequency of complement factor gene alleles also differs depending on race, data from foreign countries cannot be directly applied to Japanese populations. Under these circumstances, the Japanese Association for Complement Research (JACR) has prepared approximately 20 items for complement-related examinations, including the 5 categories of functional analysis, complement factors, complement regulators, activation products, and autoantibodies.
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Affiliation(s)
- Katsuki Ohtani
- Department of Food Science and Human Wellness, Rakuno Gakuen University, Ebetsu, Japan,
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The Immunopathology of Complement Proteins and Innate Immunity in Autoimmune Disease. Clin Rev Allergy Immunol 2020; 58:229-251. [PMID: 31834594 DOI: 10.1007/s12016-019-08774-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The complement is a powerful cascade of the innate immunity and also acts as a bridge between innate and acquired immune defence. Complement activation can occur via three distinct pathways, the classical, alternative and lectin pathways, each resulting in the common terminal pathway. Complement activation results in the release of a range of biologically active molecules that significantly contribute to immune surveillance and tissue homeostasis. Several soluble and membrane-bound regulatory proteins restrict complement activation in order to prevent complement-mediated autologous damage, consumption and exacerbated inflammation. The crucial role of complement in the host homeostasis is illustrated by association of both complement deficiency and overactivation with severe and life-threatening diseases. Autoantibodies targeting complement components have been described to alter expression and/or function of target protein resulting in a dysregulation of the delicate equilibrium between activation and inhibition of complement. The spectrum of diseases associated with complement autoantibodies depends on which complement protein and activation pathway are targeted, ranging from autoimmune disorders to kidney and vascular diseases. Nevertheless, these autoantibodies have been identified as differential biomarkers for diagnosis or follow-up of disease only in a small number of clinical conditions. For some autoantibodies, a clear relationship with clinical manifestations has been identified, such as anti-C1q, anti-Factor H, anti-C1 Inhibitor antibodies and C3 nephritic factor. For other autoantibodies, the origin and the functional consequences still remain to be elucidated, questioning about the pathophysiological significance of these autoantibodies, such as anti-mannose binding lectin, anti-Factor I, anti-Factor B and anti-C3b antibodies. The detection of autoantibodies targeting complement components is performed in specialized laboratories; however, there is no consensus on detection methods and standardization of the assays is a real challenge. This review summarizes the current panorama of autoantibodies targeting complement recognition proteins of the classical and lectin pathways, associated proteases, convertases, regulators and terminal components, with an emphasis on autoantibodies clearly involved in clinical conditions.
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Hair P, Goldman DW, Li J, Petri M, Krishna N, Cunnion K. Classical complement activation on human erythrocytes in subjects with systemic lupus erythematosus and a history of autoimmune hemolytic anemia. Lupus 2020; 29:1179-1188. [PMID: 32659155 DOI: 10.1177/0961203320936347] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
INTRODUCTION Autoimmune hemolytic anemia (AIHA) is a serious manifestation of systemic lupus erythematosus (SLE) associated with significant morbidity and mortality. In order to more fully understand the causative pathways, we utilized sera from subjects with SLE and active AIHA, or a history of AIHA, to evaluate the classical complement pathway, anti-erythrocyte antibodies, and immune complexes. METHODS To evaluate antibody-mediated complement activation on the surface of erythrocytes, as occurs in AIHA, blood type O erythrocytes were incubated with sera from 19 subjects with SLE and a history of AIHA. Circulating anti-erythrocyte antibodies and immune complexes were measured with ELISA-based assays. RESULTS In total, 90% of subjects with SLE and a history of AIHA, but not active clinical hemolysis, had measurable anti-erythrocyte antibodies. Of those with anti-erythrocyte antibody, 53% demonstrated complement opsonization on the erythrocyte surface >twofold above negative control and 29% generated the anaphylatoxin C5a. CONCLUSIONS For subjects with SLE and a history of AIHA, the persistence of circulating anti-erythrocyte antibodies and resultant erythrocyte complement opsonization and anaphylatoxin generation suggests the possibility that these complement effectors contribute to chronic morbidity and risk of AIHA relapse.
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Affiliation(s)
- Pamela Hair
- Eastern Virginia Medical School Pediatric Research, Department of Pediatrics, Norfolk, VA
| | - Daniel W Goldman
- Johns Hopkins University School of Medicine, Division of Rheumatology, Baltimore, MD
| | - Jessica Li
- Johns Hopkins University School of Medicine, Division of Rheumatology, Baltimore, MD
| | - Michelle Petri
- Johns Hopkins University School of Medicine, Division of Rheumatology, Baltimore, MD
| | - Neel Krishna
- Eastern Virginia Medical School, Department of Microbiology and Molecular Cell Biology, Norfolk, VA
| | - Kenji Cunnion
- Eastern Virginia Medical School Pediatric Research, Department of Pediatrics, Norfolk, VA
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Mihaylova G, Vasilev V, Kosturkova MB, Stoyanov GS, Radanova M. Long Non-Coding RNAs as New Biomarkers in Lupus Nephritis: A Connection Between Present and Future. Cureus 2020; 12:e9003. [PMID: 32775083 PMCID: PMC7402529 DOI: 10.7759/cureus.9003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Lupus nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE). LN often leads to kidney failure, affecting the quality of a patient's life. There are several classical biomarkers that assist nephrologists’ daily practice. For more than 50 years, anti-double stranded DNA antibodies and complement components C3 and C4 have been used for LN disease activity evaluation. The major obstacle in the usage of conventional biomarkers is that none of them have both high specificity and high sensitivity. Moreover, an invasive kidney biopsy is still the gold standard for renal involvement detection in SLE patients. Therefore, new non-invasive biomarkers are needed for the early and accurate establishment of LN. Among the promising candidates are long non-coding RNAs (lncRNAs). Their dysregulation appears to have predictive and diagnostic potential. Furthermore, these biomarkers like other conventional biomarkers give insight into the pathogenesis of LN. This review aims to summarize the available information on lncRNAs in SLE patients and to present their future opportunities to add to the conventional biomarkers in the diagnosis and monitoring of LN.
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Affiliation(s)
- Galya Mihaylova
- Biochemistry, Molecular Medicine and Nutrigenomics, Medical University of Varna, Varna, BGR
| | - Vasil Vasilev
- Nephrology, "Tsaritsa Yoanna - ISUL" University Hospital, Sofia, BGR
| | | | - George S Stoyanov
- General and Clinical Pathology/Forensic Medicine and Deontology, Medical University of Varna, Varna, BGR
| | - Maria Radanova
- Biochemistry, Molecular Medicine and Nutrigenomics, Medical University of Varna, Varna, BGR
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Segelmark M. Serological testing in small vessel vasculitis. Rheumatology (Oxford) 2020; 59:iii51-iii54. [PMID: 32348521 DOI: 10.1093/rheumatology/kez633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/30/2019] [Indexed: 11/13/2022] Open
Abstract
Serological analysis has a central role in the diagnostic work-up of patients with suspected small vessel vasculitis, both for establishing a specific diagnosis and for the monitoring of response to therapy. Autoantibodies can be detected in all forms of primary small vessel vasculitis as well as in the most common forms of secondary vasculitis. For primary vasculitis the most important serological test is for ANCA. ANCA can be found in 75-95% of patients with pauci-immune small vessel vasculitis leading to this subgroup of vasculitides being named ANCA associated vasculitis. ANCA levels often follow this disease course, but the value of serial ANCA testing is controversial. Other important autoantibodies in primary small vessel vasculitis are anti-glomerular basement membrane antibodies, anti-C1q, anti-galactose deficient IgA and cryoglobulins. A wide variety of systemic inflammatory diseases and infections can be complicated by small vessel vasculitis and detected by serological testing. Important examples are SLE, rheumatoid arthritis, Hepatitis C and HIV.
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Affiliation(s)
- Mårten Segelmark
- Department of Clinical Sciences, Nephrology, Skane University Hospital, Lund University, Lund, Sweden
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15
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Complement activation and regulation in rheumatic disease. Semin Immunol 2019; 45:101339. [DOI: 10.1016/j.smim.2019.101339] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 10/24/2019] [Accepted: 10/24/2019] [Indexed: 01/02/2023]
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Segelmark M, Björck L. Streptococcal Enzymes as Precision Tools Against Pathogenic IgG Autoantibodies in Small Vessel Vasculitis. Front Immunol 2019; 10:2165. [PMID: 31616410 PMCID: PMC6763725 DOI: 10.3389/fimmu.2019.02165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/28/2019] [Indexed: 11/24/2022] Open
Abstract
In primary systemic small vessel vasculitis autoantibodies are common and seem to play an important role in the pathogenesis. Autoantibodies in vasculitis are preferentially directed against components of the immune system or directly against components of the vessel wall. Plasmapheresis is often applied in emergency situationists when the function of vital organs is jeopardized, the level of clinical evidence to apply such therapy, however, varies between low and non-existing. Plasmapheresis is a blunt and unspecific instrument that requires several sessions to achieve a substantial reduction of autoantibody levels. IdeS and EndoS are two relatively recently discovered enzymes produced by S. pyogenes, that have a remarkable capacity to degrade and disarm IgG. They have shown positive results in several in vivo models of autoimmunity, and treatment with IdeS has successfully been used to inactivate HLA alloantibodies in patients undergoing renal transplantation. Both IdeS and EndoS have the potential to become precision tools to replace plasmapheresis in the treatment of vasculitic emergencies and a clinical trial of IdeS in anti-GBM vasculitis is now ongoing.
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Affiliation(s)
- Mårten Segelmark
- Nephrology, Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Lars Björck
- Infection Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden
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Caster DJ, Merchant ML, Klein JB, Powell DW. Precision medicine in lupus nephritis: can biomarkers get us there? Transl Res 2018; 201:26-39. [PMID: 30179587 PMCID: PMC6415919 DOI: 10.1016/j.trsl.2018.08.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 08/04/2018] [Accepted: 08/07/2018] [Indexed: 01/08/2023]
Abstract
Patients with systemic lupus erythematosus frequently develop lupus nephritis (LN), a condition that can lead to end-stage kidney disease. Multiple serum and urine biomarkers for LN have been proposed in recent years, yet none have become incorporated into clinical use. The majority of studies have been single center with significant variability in cohorts, assays, and sample storage, leading to inconclusive results. It has become clear that no single biomarker is likely to be sufficient to diagnose LN, identify flares, and define the response to therapy and prognosis. A more likely scenario is a panel of urine, serum, tissue, and genetic biomarkers. In this review, we summarize traditional and novel biomarkers and discuss how they may be utilized in order to bring precision medicine to clinical practice in LN.
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Affiliation(s)
- Dawn J Caster
- Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; Robley Rex Veterans Affairs Medical Center, Louisville, Kentucky.
| | - Michael L Merchant
- Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
| | - Jon B Klein
- Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; Robley Rex Veterans Affairs Medical Center, Louisville, Kentucky
| | - David W Powell
- Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky
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Ekdahl KN, Persson B, Mohlin C, Sandholm K, Skattum L, Nilsson B. Interpretation of Serological Complement Biomarkers in Disease. Front Immunol 2018; 9:2237. [PMID: 30405598 PMCID: PMC6207586 DOI: 10.3389/fimmu.2018.02237] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 09/10/2018] [Indexed: 01/07/2023] Open
Abstract
Complement system aberrations have been identified as pathophysiological mechanisms in a number of diseases and pathological conditions either directly or indirectly. Examples of such conditions include infections, inflammation, autoimmune disease, as well as allogeneic and xenogenic transplantation. Both prospective and retrospective studies have demonstrated significant complement-related differences between patient groups and controls. However, due to the low degree of specificity and sensitivity of some of the assays used, it is not always possible to make predictions regarding the complement status of individual patients. Today, there are three main indications for determination of a patient's complement status: (1) complement deficiencies (acquired or inherited); (2) disorders with aberrant complement activation; and (3) C1 inhibitor deficiencies (acquired or inherited). An additional indication is to monitor patients on complement-regulating drugs, an indication which may be expected to increase in the near future since there is now a number of such drugs either under development, already in clinical trials or in clinical use. Available techniques to study complement include quantification of: (1) individual components; (2) activation products, (3) function, and (4) autoantibodies to complement proteins. In this review, we summarize the appropriate indications, techniques, and interpretations of basic serological complement analyses, exemplified by a number of clinical disorders.
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Affiliation(s)
- Kristina N Ekdahl
- Rudbeck Laboratory C5:3, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Centre of Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
| | - Barbro Persson
- Rudbeck Laboratory C5:3, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Camilla Mohlin
- Centre of Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
| | - Kerstin Sandholm
- Centre of Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
| | - Lillemor Skattum
- Section of Microbiology, Immunology and Glycobiology, Department of Laboratory Medicine, Clinical Immunology and Transfusion Medicine, Lund University, Lund, Sweden
| | - Bo Nilsson
- Rudbeck Laboratory C5:3, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
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Two-Parametric Immunological Score Development for Assessing Renal Involvement and Disease Activity in Systemic Lupus Erythematosus. J Immunol Res 2018; 2018:1294680. [PMID: 30246032 PMCID: PMC6136571 DOI: 10.1155/2018/1294680] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 06/05/2018] [Accepted: 06/13/2018] [Indexed: 01/09/2023] Open
Abstract
Objective Anti-double-stranded (ds) DNA and anti-C1q autoantibodies are useful tools in the assessment of disease activity and nephritis in systemic lupus erythematosus (SLE) patients. This study aimed to explore the utility of these antibodies along with anti-Ku antibodies in an oligoparametric model approach for the assessment of disease activity and lupus nephritis. Methods Samples from 261 well-characterized SLE patients were tested using chemiluminescent immunoassays (CIA) for anti-dsDNA and anti-Ku antibodies as well as by anti-C1q antibody ELISA (Inova Diagnostics, USA). Of these SLE patients, 26.4% had lupus nephritis (LN) at the time of blood draw or had a history of LN, and modified SLE disease activity index-2K (SLEDAI) scores were used to assess disease activity. Results All three antibodies demonstrated higher prevalence and higher antibody levels in active versus inactive SLE patients and in LN versus non-LN patients. When oligoparametric analysis was performed, the likelihood of LN and patients with active disease increased with dual and triple positivity. Conclusions Anti-dsDNA and anti-C1q antibodies are useful tools to identify disease activity and/or renal involvement in SLE patients. In addition, the combination of those antibodies in a two-parametric score might improve the clinical utility of those markers.
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Sjöwall C, Mandl T, Skattum L, Olsson M, Mohammad AJ. Epidemiology of hypocomplementaemic urticarial vasculitis (anti-C1q vasculitis). Rheumatology (Oxford) 2018; 57:1400-1407. [PMID: 29718374 DOI: 10.1093/rheumatology/key110] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Indexed: 11/12/2022] Open
Abstract
Objectives The aim was to describe the clinical characteristics and epidemiology of hypocomplementaemic urticarial vasculitis (HUV; anti-C1q vasculitis) in two geographically defined areas of Sweden. Methods In the health-care districts surrounding Skåne University Hospital (mean population 950 560) and Linköping University Hospital (mean population 428 503), all incident cases of HUV residing within the study areas at the onset of disease were identified during the years 2000-15. The diagnosis of HUV was confirmed by review of medical records. Only patients meeting the proposed diagnostic HUV criteria and/or the 2012 Chapel Hill consensus definitions in combination with an ever-positive anti-C1q antibody test were included. Results Sixteen patients (14 females) were identified during the study period. The median (interquartile range) age at diagnosis was 51 (40.7-56.7) years. Median (interquartile range) time of follow-up from diagnosis to 31 December 2015, or death, was 94 (46.5-136.2) months. The most frequent manifestations at diagnosis were urticaria (100%), arthritis (88%), followed by biopsy-proven glomerulonephritis (19%), episcleritis/scleritis (19%) and recurrent abdominal pain (13%). The annual incidence rate per million inhabitants was estimated as 0.7 (95% CI: 0.4, 1.1). Sixty-three per cent suffered from pulmonary disease at the last follow-up. Two patients died during the follow-up period. One patient underwent lung transplantation, and two patients proceeded to end-stage renal disease. The point prevalence on 31 December 2015 was 9.5/million (95% CI: 4.5, 14.5). Conclusion Hypocomplementaemic urticarial vasculitis constitutes a rare, but not always benign condition. Renal and lung manifestations were severe in some cases, highlighting the need for careful screening and monitoring of this potentially serious condition.
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Affiliation(s)
- Christopher Sjöwall
- Division of Neuro & Inflammation Sciences, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Thomas Mandl
- Department of Clinical Sciences Malmö, Rheumatology, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Lillemor Skattum
- Clinical Immunology and Transfusion Medicine, Office for Medical Services, Lund, Sweden.,Department of Laboratory Medicine, Section of Microbiology, Immunology and Glycobiology, Lund University, Lund, Sweden
| | - Martin Olsson
- Clinical Immunology and Transfusion Medicine, Office for Medical Services, Lund, Sweden
| | - Aladdin J Mohammad
- Department of Clinical Sciences Lund, Rheumatology, Lund University, Skåne University Hospital, Lund, Sweden.,Department of Medicine, University of Cambridge, Cambridge, UK
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Alelign T, Ahmed MM, Bobosha K, Tadesse Y, Howe R, Petros B. Kidney Transplantation: The Challenge of Human Leukocyte Antigen and Its Therapeutic Strategies. J Immunol Res 2018; 2018:5986740. [PMID: 29693023 PMCID: PMC5859822 DOI: 10.1155/2018/5986740] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 11/30/2017] [Accepted: 12/03/2017] [Indexed: 12/16/2022] Open
Abstract
Kidney transplantation remains the treatment of choice for end-stage renal failure. When the immune system of the recipient recognizes the transplanted kidney as a foreign object, graft rejection occurs. As part of the host immune defense mechanism, human leukocyte antigen (HLA) is a major challenge for graft rejection in transplantation therapy. The impact of HLA mismatches between the donor and the potential recipient prolongs the time for renal transplantation therapy, tethered to dialysis, latter reduces graft survival, and increases mortality. The formation of pretransplant alloantibodies against HLA class I and II molecules can be sensitized through exposures to blood transfusions, prior transplants, and pregnancy. These preformed HLA antibodies are associated with rejection in kidney transplantation. On the other hand, the development of de novo antibodies may increase the risk for acute and chronic rejections. Allograft rejection results from a complex interplay involving both the innate and the adaptive immune systems. Thus, further insights into the mechanisms of tissue rejection and the risk of HLA sensitization is crucial in developing new therapies that may blunt the immune system against transplanted organs. Therefore, the purpose of this review is to highlight facts about HLA and its sensitization, various mechanisms of allograft rejection, the current immunosuppressive approaches, and the directions for future therapy.
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Affiliation(s)
- Tilahun Alelign
- College of Natural Sciences, Department of Microbial, Cellular and Molecular Biology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
- Department of Biology, Debre Berhan University, P.O. Box 445, Debre Berhan, Ethiopia
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Momina M. Ahmed
- St. Paul's Hospital Millennium Medical College and Addis Ababa University, Addis Ababa, Ethiopia
| | - Kidist Bobosha
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Yewondwossen Tadesse
- School of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Rawleigh Howe
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Beyene Petros
- College of Natural Sciences, Department of Microbial, Cellular and Molecular Biology, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
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Trouw LA, Pickering MC, Blom AM. The complement system as a potential therapeutic target in rheumatic disease. Nat Rev Rheumatol 2017; 13:538-547. [DOI: 10.1038/nrrheum.2017.125] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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23
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Ricklin D, Barratt-Due A, Mollnes TE. Complement in clinical medicine: Clinical trials, case reports and therapy monitoring. Mol Immunol 2017; 89:10-21. [PMID: 28576323 DOI: 10.1016/j.molimm.2017.05.013] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 05/15/2017] [Accepted: 05/19/2017] [Indexed: 01/13/2023]
Abstract
Research during past decades made it evident that complement is involved in more tasks than fighting infections, but has important roles in other immune surveillance and housekeeping functions. If the balance between complement activation and regulation is out of tune, however, complement can quickly turn against the host and contribute to adverse processes that result in various clinical conditions. Whereas clinical awareness was initially focused on complement deficiencies, excessive activation and insufficient regulation are frequently the dominant factors in complement-related disorders. The individual complement profile of a patient often determines the course and severity of the disease, and the pathophysiological involvement of complement may be highly diverse. As a consequence, complement assays have evolved as essential tools not only in initial diagnosis but also for following disease progression and for monitoring complement-targeted therapies, which become increasingly available in routine clinical use. We herein review the current state of complement-directed drug candidates in clinical evaluation and provide an overview of extended indications considered for the FDA-approved inhibitor eculizumab. Furthermore we review the literature describing cases reports and case series where eculizumab has been used "off-label". Finally, we give a summary of the currently available tests to measure complement profiles and discuss their suitability in diagnostics and treatment monitoring. With complement finally entering the clinical arena, there are intriguing opportunities for treating complement-mediated diseases. However, this progress also requires a new awareness about complement pathophysiology, adequate diagnostic tools and suitable treatment options among clinicians treating patients with such disorders.
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Affiliation(s)
- Daniel Ricklin
- Department of Pharmaceutical Sciences, University of Basel, Switzerland.
| | - Andreas Barratt-Due
- Department of Immunology, Oslo University Hospital, and K. G. Jebsen Inflammation Research Centre, University of Oslo, Norway; Department of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway
| | - Tom Eirik Mollnes
- Department of Immunology, Oslo University Hospital, and K. G. Jebsen Inflammation Research Centre, University of Oslo, Norway; Research Laboratory Nordland Hospital, Bodø, and K. G. Jebsen TREC, University of Tromsø, Tromsø, Norway; Centre of Molecular Inflammation, Norwegian University of Science and Technology, Trondheim, Norway.
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Kabeerdoss J, Gupta N, Pulukool S, Mohan H, Mahasampath G, Danda D. Anti-C1q Antibody is Associated with Renal and Cutaneous Manifestations in Asian Indian Patients with Systemic Lupus Erythematosus. J Clin Diagn Res 2017; 11:OC39-OC42. [PMID: 28511434 DOI: 10.7860/jcdr/2017/22661.9545] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/11/2016] [Indexed: 11/24/2022]
Abstract
INTRODUCTION C1q play an important role in clearance of immune complexes and apoptotic cell debris. Impaired clearance leads to exposure of C1 native antigen and development of anti-C1q antibody formation. Anti-C1q antibody is well studied in Systemic Lupus Erythematosus (SLE). Significance of anti-C1q Ab in Indian SLE patients and their clinical manifestations is not clear. AIM The aim of this study was to investigate associations between anti-C1q antibody and clinical as well as serological markers of SLE. MATERIALS AND METHODS Retrospective study of SLE patients fulfilling either American College of Rheumatology (ACR) 1990 or Systemic Lupus International Collaborating Clinics (SLICC) 2012 classification criteria were recruited from inpatients and outpatients services of the Clinical immunology and Rheumatology Department, Christian Medical College at Vellore, India between March 2013 and January 2015. Anti-C1q antibody was assayed by ELISA (Demeditec Diagnostics GmbH, Germany). Logistic regression analysis was performed to find the association of anti-C1q antibodies with serological and clinical parameters in SLE including Lupus Nephritis (LN). RESULTS Sixty nine patients (54.76%) out of 126 SLE patients had LN. Anti-C1q levels were higher in patients with LN as compared to those without (p<0.05). Anti-C1q antibody was also significantly associated with positive C1q immunofluorescence staining in renal biopsy specimens (p<0.05). Overall, renal Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) {OR 1.35 (1.08-1.69)}, low C4 {OR 3.11 (1.04-9.26)} and mucocutaneous manifestation {OR 4.72 (1.38-16.05)} were independently associated with anti-C1q levels in serum. CONCLUSION Renal SLEDAI, low C4 and mucocutaneous manifestations were independently associated with raised anti C1q antibody in SLE patients.
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Affiliation(s)
- Jayakanthan Kabeerdoss
- Lecturer, Department of Rheumatology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Nikhil Gupta
- PG Registrar, Department of Rheumatology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Sandhya Pulukool
- Associate Professor, Department of Rheumatology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Hindhumathi Mohan
- Junior Research Fellow, Department of Rheumatology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Gowri Mahasampath
- Associate Research Officer, Department of Biostatistics, Christian Medical College, Vellore, Tamil Nadu, India
| | - Debashish Danda
- Professor and Head, Department of Rheumatology, Christian Medical College, Vellore, Tamil Nadu, India
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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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26
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Vignesh P, Rawat A, Sharma M, Singh S. Complement in autoimmune diseases. Clin Chim Acta 2017; 465:123-130. [PMID: 28040558 DOI: 10.1016/j.cca.2016.12.017] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 12/15/2016] [Accepted: 12/17/2016] [Indexed: 12/18/2022]
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27
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Vitkova H, Jiskra J, Springer D, Limanova Z, Telicka Z, Bartakova J, Trendelenburg M, Potlukova E. Anti-C1q autoantibodies are linked to autoimmune thyroid disorders in pregnant women. Clin Exp Immunol 2016; 186:10-7. [PMID: 27198614 DOI: 10.1111/cei.12813] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2016] [Indexed: 01/24/2023] Open
Abstract
Anti-C1q antibodies (anti-C1q) have been implicated in the pathogenesis of autoimmune diseases, including autoimmune thyroid disorders (AITD). The aim of this study was to evaluate the association between anti-C1q and thyroid function in pregnancy-associated AITD. In 96 pregnant women screened positive for AITD (thyroid dysfunction and/or antibodies against thyroperoxidase - TPOAb), anti-C1q were measured during the 9-11th gestational week and after delivery (median 16 months after delivery), and compared to the corresponding serum levels of thyroid hormones. As controls, 80 healthy pregnant women, 72 non-pregnant AITD patients and 72 blood donors were included. In the non-pregnant AITD group, two serum samples ≥ 6 months apart were analysed. Compared to blood donors, anti-C1q levels were substantially higher in all pregnant women analysed. In pregnancy, anti-C1q levels were higher in the TPOAb-positive women than in controls (37 versus 17·5%, P < 0·0001). Anti-C1q-positive pregnant women screened positive for AITD had higher thyroid-stimulating hormone (TSH) levels than anti-C1q-negative women (2·41 versus 1·94 mU/l, P = 0·01), and TSH correlated positively with anti-C1q (r = 0·226, P = 0·045) in the TPOAb-positive women. After delivery, serum levels of anti-C1q decreased in the positively screened TPOAb-negative women (8·8 versus 5·9 U/l, P = 0·002), but not in the TPOAb-positive ones, and they no longer correlated with TSH. Anti-C1q antibody levels increase during pregnancy in general and even more in the context of AITD, where they correlate with thyroid stimulating hormone levels.
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Affiliation(s)
- H Vitkova
- Third Department of Medicine, General University Hospital and First Faculty of Medicine, Charles University in Prague, Czech Republic
| | - J Jiskra
- Third Department of Medicine, General University Hospital and First Faculty of Medicine, Charles University in Prague, Czech Republic
| | - D Springer
- Institute of Clinical Biochemistry and Laboratory Medicine, General University Hospital in Prague, Czech Republic
| | - Z Limanova
- Third Department of Medicine, General University Hospital and First Faculty of Medicine, Charles University in Prague, Czech Republic
| | - Z Telicka
- Third Department of Medicine, General University Hospital and First Faculty of Medicine, Charles University in Prague, Czech Republic
| | - J Bartakova
- Institute of Biophysics and Informatics, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
| | - M Trendelenburg
- Division of Internal Medicine and Laboratory of Clinical Immunology, University Hospital Basel
| | - E Potlukova
- Division of Internal Medicine, University Hospital Basel
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Prohászka Z, Nilsson B, Frazer-Abel A, Kirschfink M. Complement analysis 2016: Clinical indications, laboratory diagnostics and quality control. Immunobiology 2016; 221:1247-58. [PMID: 27475991 DOI: 10.1016/j.imbio.2016.06.008] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 06/10/2016] [Accepted: 06/10/2016] [Indexed: 10/21/2022]
Abstract
In recent years, complement analysis of body fluids and biopsies, going far beyond C3 and C4, has significantly enhanced our understanding of the disease process. Such expanded complement analysis allows for a more precise differential diagnosis and for critical monitoring of complement-targeted therapy. These changes are a result of the growing understanding of the involvement of complement in a diverse set of disorders. To appreciate the importance of proper complement analysis, it is important to understand the role it plays in disease. Historically, it was the absence of complement as manifested in severe infection that was noted. Since then complement has been connected to a variety of inflammatory disorders, such as autoimmune diseases and hereditary angioedema. While the role of complement in the rejection of renal grafts has been known longer, the significant impact of complement. In certain nephropathies has now led to the reclassification of some rare kidney diseases and an increased role for complement analysis in diagnosis. Even more unexpected is that complement has also been implicated in neural, ophtalmological and dermatological disorders. With this level of involvement in some varied and impactful health issues proper complement testing is clearly important; however, analysis of the complement system varies widely among laboratories. Except for a few proteins, such as C3 and C4, there are neither well-characterized standard preparations nor calibrated assays available. This is especially true for the inter-laboratory variation of tests which assess classical, alternative, or lectin pathway function. In addition, there is a need for the standardization of the measurement of complement activation products that are so critical in determining whether clinically relevant complement activation has occurred in vivo. Finally, autoantibodies to complement proteins (e.g. anti-C1q), C3 and C4 convertases (C3 and C4 nephritic factor) or to regulatory proteins (e.g. anti-C1inhibitor, anti-factor H) are important in defining autoimmune processes and diseases based on complement dysregulation. To improve the quality of complement laboratory analysis a standardization commmittee of the International Complement Society (ICS) and the International Union of Immunological Societies (IUIS) was formed to provide guidelines for modern complement analysis and standards for the development of international testing programs.
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Affiliation(s)
- Zoltán Prohászka
- 3rd Department of Internal Medicine, Research Laboratory and Füst György Complement Diagnostic Laboratory, Semmelweis University, Budapest, Hungary
| | - Bo Nilsson
- Clinical Immunology, Rudbeck Laboratory (C5), University Hospital, Uppsala, Sweden
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Magro-Checa C, Schaarenburg RA, Beaart HJL, Huizinga TWJ, Steup-Beekman GM, Trouw LA. Complement levels and anti-C1q autoantibodies in patients with neuropsychiatric systemic lupus erythematosus. Lupus 2016; 25:878-88. [DOI: 10.1177/0961203316643170] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Objective The objective of this paper is to analyse serum levels of anti-C1q, C1q circulating immune complexes (CIC), complement activation and complement components in systemic lupus erythematosus (SLE) patients during the first central nervous system neuropsychiatric (NP) event and to define the possible association between these results and clinical and laboratory characteristics. Methods A total of 280 patients suspected of having NP involvement due to SLE were recruited in the Leiden NPSLE-clinic. All SLE patients were classified according to the ACR 1982 revised criteria for the classification of SLE. The clinical disease activity was measured by the SLE Disease Activity Index 2000 (SLEDAI-2K) and NP diagnoses were classified according to the 1999 ACR case definitions for NPSLE. We measured in serum of all patients anti-C1q and C1q CIC levels, the activation capacity of complement (CH50 and AP50) and different complement components (C1q, C3, C4). Results In 92 patients the symptoms were attributed to SLE. NPSLE patients consisted of 63 patients with focal NPSLE and 34 patients with diffuse NPSLE. Anti-C1q antibodies were significantly higher and CH50, AP50 and C3 were significantly lower in NPSLE patients compared with SLE patients without NPSLE. This association was specially marked for diffuse NPSLE while no differences were found for focal NPSLE. After using potential predictors, decreased C4 remained significantly associated with focal NPSLE, but only when antiphospholipid antibodies (aPL) were included in the model. C3 and AP50 were independently associated with diffuse NPSLE. When SLEDAI-2K was included in the model these two associations were lost. When individual NPSLE syndromes were analysed, psychosis and cognitive dysfunction showed significantly lower values of complement activation capacity and all complement components. No significant associations were seen for other individual NPSLE syndromes. Conclusion The associations between diffuse NPSLE and anti-C1q, C3/AP50 and focal NPSLE and C4 may be explained by disease activity and the presence of aPL, respectively. The role of complement activation and complement components in lupus psychosis and cognitive dysfunction merits further research.
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Affiliation(s)
- C Magro-Checa
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | - R A Schaarenburg
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | - H J L Beaart
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | - T W J Huizinga
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | - G M Steup-Beekman
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
| | - L A Trouw
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands
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Mahayidin H, Yahya NK, Wan Ghazali WS, Mohd Ismail A, Wan Ab Hamid WZ. Evaluation of Endothelial Cell Adhesion Molecules and Anti-C1q Antibody in Discriminating between Active and Non-Active Systemic Lupus Erythematosus. Malays J Med Sci 2016; 23:22-31. [PMID: 27418866 PMCID: PMC4934715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 04/09/2016] [Indexed: 06/06/2023] Open
Abstract
BACKGROUND Detecting the active state of systemic lupus erythematosus (SLE) is important but challenging. This study aimed to determine the diagnostic accuracy of serum endothelial cell adhesion molecules (ICAM-1 and VCAM-1) and anti-C1q antibody in discriminating between active and non-active SLE. METHODS Using SELENA-SLE disease activity index (SLEDAI), 95 SLE patients (45 active and 50 non-active) were assessed. A score above five was considered indicative of active SLE. The blood samples were tested for serum ICAM-1, VCAM-1 and anti-C1q antibody using enzyme-linked immunosorbent assay (ELISA). RESULTS The levels of serum VCAM-1 and anti-C1q antibody were significantly higher in active SLE patients. Both VCAM-1 and anti-C1q were able to discriminate between active and non-active SLE (p-value < 0.001 and 0.005, respectively). From the receiver operating characteristic curves (ROCs) constructed, the optimal cut-off values for VCAM-1 and anti-C1q antibody in discriminating between active and non-active SLE were 30.5 ng/mL (69.0% sensitivity, 60.0% specificity, PPV 58.5%, NPV 66.7%) and 7.86 U/mL (75.6% sensitivity, 80% specificity, PPV 77.3%, NPV 78.4%), respectively. However, serum ICAM-1 level was unable to discriminate between the two groups (p-value = 0.193). CONCLUSION Anti-C1q antibody demonstrated the best diagnostic accuracy in discriminating between active and non-active SLE patients.
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Affiliation(s)
- Hasni Mahayidin
- Department of Pathology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Nurul Khaiza Yahya
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Wan Syamimee Wan Ghazali
- Department of Medicine, Hospital Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Asmahan Mohd Ismail
- Department of Medicine, Hospital Raja Perempuan Zainab II, 15000 Kota Bharu, Kelantan, Malaysia
| | - Wan Zuraida Wan Ab Hamid
- Department of Immunology, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, 16150 Kubang Kerian, Kelantan, Malaysia
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Correlation of Serum Soluble Interleukin-7 Receptor and Anti-C1q Antibody in Patients with Systemic Lupus Erythematosus. Autoimmune Dis 2016; 2016:8252605. [PMID: 27069677 PMCID: PMC4812203 DOI: 10.1155/2016/8252605] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Accepted: 02/15/2016] [Indexed: 11/17/2022] Open
Abstract
Background. Serum concentrations of soluble interleukin-7 receptor (sIL-7R) and anti-C1q antibody have recently been identified as unique serological markers for lupus nephritis (LN) in patients with systemic lupus erythematosus (SLE). In this study, we evaluated the correlation of serum sIL-7R and anti-C1q in SLE patients. Methods. Sera from 134 patients with SLE and 84 healthy cohorts were tested for levels of sIL-7R and anti-C1q antibodies in terms of ELISA. Correlations of the sIL-7R and anti-C1q autoantibodies were evaluated. Results. The serum concentrations of sIL-7R and anti-C1q antibodies were significantly higher in SLE patients and LN patients in comparison with healthy individuals/controls and SLE patients with non-LN, respectively. In addition, both sIL-7R and anti-C1q concentrations were found to significantly correlate with the SLE disease activity as evaluated by SLEDAI scores. Interestingly, the serum sIL-7R concentration was strongly correlated with the level of anti-C1q antibodies (r = 0.2871, p = 0.0008) but not statistically correlated with other serological markers, including the anti-dsDNA and complements C3 and C4 concentrations in SLE patients. Conclusion. Both serum sIL-7R and anti-C1q antibodies were strongly associated with disease activity and LN in SLE patients, suggesting that they may be reliable serological markers for identification of SLE patients with active diseases and LN.
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Lintner KE, Wu YL, Yang Y, Spencer CH, Hauptmann G, Hebert LA, Atkinson JP, Yu CY. Early Components of the Complement Classical Activation Pathway in Human Systemic Autoimmune Diseases. Front Immunol 2016; 7:36. [PMID: 26913032 PMCID: PMC4753731 DOI: 10.3389/fimmu.2016.00036] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 01/24/2016] [Indexed: 01/06/2023] Open
Abstract
The complement system consists of effector proteins, regulators, and receptors that participate in host defense against pathogens. Activation of the complement system, via the classical pathway (CP), has long been recognized in immune complex-mediated tissue injury, most notably systemic lupus erythematosus (SLE). Paradoxically, a complete deficiency of an early component of the CP, as evidenced by homozygous genetic deficiencies reported in human, are strongly associated with the risk of developing SLE or a lupus-like disease. Similarly, isotype deficiency attributable to a gene copy-number (GCN) variation and/or the presence of autoantibodies directed against a CP component or a regulatory protein that result in an acquired deficiency are relatively common in SLE patients. Applying accurate assay methodologies with rigorous data validations, low GCNs of total C4, and heterozygous and homozygous deficiencies of C4A have been shown as medium to large effect size risk factors, while high copy numbers of total C4 or C4A as prevalent protective factors, of European and East-Asian SLE. Here, we summarize the current knowledge related to genetic deficiency and insufficiency, and acquired protein deficiencies for C1q, C1r, C1s, C4A/C4B, and C2 in disease pathogenesis and prognosis of SLE, and, briefly, for other systemic autoimmune diseases. As the complement system is increasingly found to be associated with autoimmune diseases and immune-mediated diseases, it has become an attractive therapeutic target. We highlight the recent developments and offer a balanced perspective concerning future investigations and therapeutic applications with a focus on early components of the CP in human systemic autoimmune diseases.
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Affiliation(s)
- Katherine E Lintner
- Center for Molecular and Human Genetics, Division of Pediatric Rheumatology, Department of Pediatrics, Nationwide Children's Hospital, The Ohio State University , Columbus, OH , USA
| | - Yee Ling Wu
- Center for Molecular and Human Genetics, Division of Pediatric Rheumatology, Department of Pediatrics, Nationwide Children's Hospital, The Ohio State University , Columbus, OH , USA
| | - Yan Yang
- Center for Molecular and Human Genetics, Division of Pediatric Rheumatology, Department of Pediatrics, Nationwide Children's Hospital, The Ohio State University , Columbus, OH , USA
| | - Charles H Spencer
- Center for Molecular and Human Genetics, Division of Pediatric Rheumatology, Department of Pediatrics, Nationwide Children's Hospital, The Ohio State University , Columbus, OH , USA
| | - Georges Hauptmann
- Laboratoire d'Immuno-Rhumatologie Moleculaire, INSERM UMR_S 1109, LabEx Transplantex, Faculté de Médecine, Université de Strasbourg , Strasbourg , France
| | - Lee A Hebert
- Division of Nephrology, College of Medicine, The Ohio State University , Columbus, OH , USA
| | - John P Atkinson
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine , St. Louis, MO , USA
| | - C Yung Yu
- Center for Molecular and Human Genetics, Division of Pediatric Rheumatology, Department of Pediatrics, Nationwide Children's Hospital, The Ohio State University , Columbus, OH , USA
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Frazer-Abel A, Sepiashvili L, Mbughuni MM, Willrich MAV. Overview of Laboratory Testing and Clinical Presentations of Complement Deficiencies and Dysregulation. Adv Clin Chem 2016; 77:1-75. [PMID: 27717414 DOI: 10.1016/bs.acc.2016.06.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Historically, complement disorders have been attributed to immunodeficiency associated with severe or frequent infection. More recently, however, complement has been recognized for its role in inflammation, autoimmune disorders, and vision loss. This paradigm shift requires a fundamental change in how complement testing is performed and interpreted. Here, we provide an overview of the complement pathways and summarize recent literature related to hereditary and acquired angioedema, infectious diseases, autoimmunity, and age-related macular degeneration. The impact of complement dysregulation in atypical hemolytic uremic syndrome, paroxysmal nocturnal hemoglobinuria, and C3 glomerulopathies is also described. The advent of therapeutics such as eculizumab and other complement inhibitors has driven the need to more fully understand complement to facilitate diagnosis and monitoring. In this report, we review analytical methods and discuss challenges for the clinical laboratory in measuring this complex biochemical system.
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34
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Correlation of Serum Soluble Interleukin-7 Receptor and Anti-C1q Antibody in Patients with Systemic Lupus Erythematosus. Autoimmune Dis 2016. [PMID: 27069677 DOI: 10.1155/2016/8252605.pmid:27069677;pmcid:pmc4812203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023] Open
Abstract
Background. Serum concentrations of soluble interleukin-7 receptor (sIL-7R) and anti-C1q antibody have recently been identified as unique serological markers for lupus nephritis (LN) in patients with systemic lupus erythematosus (SLE). In this study, we evaluated the correlation of serum sIL-7R and anti-C1q in SLE patients. Methods. Sera from 134 patients with SLE and 84 healthy cohorts were tested for levels of sIL-7R and anti-C1q antibodies in terms of ELISA. Correlations of the sIL-7R and anti-C1q autoantibodies were evaluated. Results. The serum concentrations of sIL-7R and anti-C1q antibodies were significantly higher in SLE patients and LN patients in comparison with healthy individuals/controls and SLE patients with non-LN, respectively. In addition, both sIL-7R and anti-C1q concentrations were found to significantly correlate with the SLE disease activity as evaluated by SLEDAI scores. Interestingly, the serum sIL-7R concentration was strongly correlated with the level of anti-C1q antibodies (r = 0.2871, p = 0.0008) but not statistically correlated with other serological markers, including the anti-dsDNA and complements C3 and C4 concentrations in SLE patients. Conclusion. Both serum sIL-7R and anti-C1q antibodies were strongly associated with disease activity and LN in SLE patients, suggesting that they may be reliable serological markers for identification of SLE patients with active diseases and LN.
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35
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Menzhinskaya IV, Van’ko LV, Kashentseva MM, Kiryushchenkov PA, Sukhikh GT. Incidence of Autoantibodies to C1Q Complement Component in Women with Miscarriages and Autoantibodies to Phospholipids and Chorionic Gonadotropin. Bull Exp Biol Med 2015; 160:260-3. [DOI: 10.1007/s10517-015-3144-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Indexed: 11/30/2022]
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36
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Chi S, Yu Y, Shi J, Zhang Y, Yang J, Yang L, Liu X. Antibodies against C1q Are a Valuable Serological Marker for Identification of Systemic Lupus Erythematosus Patients with Active Lupus Nephritis. DISEASE MARKERS 2015; 2015:450351. [PMID: 26549923 PMCID: PMC4621353 DOI: 10.1155/2015/450351] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 09/21/2015] [Indexed: 11/17/2022]
Abstract
OBJECTIVE An early diagnosis of lupus nephritis (LN) has an important clinical implication in guiding treatments of systemic lupus erythematosus (SLE) in clinical settings. In this study, the diagnostic values of circulating autoantibodies to C1q alone or in combination with other markers for accessing active SLE and LN were evaluated. METHODS The diagnostic value of anti-C1q autoantibodies for identification of patients with active SLE disease and LN was evaluated by analyzing the level of anti-C1q antibodies in sera from 95 SLE patients, 40 non-SLE patients, and 34 healthy cohorts. RESULTS The prevalence of anti-C1q antibodies was significantly higher in patients with SLE (50/95, 52.6%), active SLE (40/51, 78.4%), and LN (30/35, 85.7%) in comparison with non-SLE patient controls, patients with inactive SLE, and non-LN, respectively. A combination of anti-C1q with anti-dsDNA and/or levels of complements C3 and C4 exhibited an increased specificity but a decreased sensitivity for identification of patients with active SLE and LN diseases relative to each of these markers alone. CONCLUSION Anti-C1q antibodies were strongly associated with disease activity and LN in SLE patients, suggesting that it may be a reliable serological marker for identification of SLE patients with active LN and active SLE disease.
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Affiliation(s)
- Shuhong Chi
- Department of Rheumatology, The General Hospital of Ningxia Medical University, Yinchuan 750004, China
| | - Yunxia Yu
- Department of Rheumatology, The General Hospital of Ningxia Medical University, Yinchuan 750004, China
| | - Juan Shi
- Center of Laboratory Medicine, The General Hospital of Ningxia Medical University, Yinchuan 750004, China
| | - Yurong Zhang
- Department of Rheumatology, The General Hospital of Ningxia Medical University, Yinchuan 750004, China
| | - Jijuan Yang
- Department of Rheumatology, The General Hospital of Ningxia Medical University, Yinchuan 750004, China
| | - Lijuan Yang
- Department of Rheumatology, The General Hospital of Ningxia Medical University, Yinchuan 750004, China
| | - Xiaoming Liu
- Institute of Human Stem Cell Research, The General Hospital of Ningxia Medical University, Yinchuan, Ningxia 750004, China
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37
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Mosaad YM, Hammad A, Fawzy Z, El-Refaaey A, Tawhid Z, Hammad EM, Youssef LF, ElAttar EAA, Radwan DF, Fawzy IM. C1q rs292001 polymorphism and C1q antibodies in juvenile lupus and their relation to lupus nephritis. Clin Exp Immunol 2015; 182:23-34. [PMID: 26095468 DOI: 10.1111/cei.12666] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2015] [Indexed: 12/17/2022] Open
Abstract
C1q deficiency is related strongly to systemic lupus erythematosus (SLE), but very few and inconsistent studies explored the single nucleotide polymorphisms of the C1q gene in relation to juvenile SLE (jSLE) and lupus nephritis (LN). The objective of this study was to analyse whether C1q rs 292001 polymorphism is associated with SLE and disease phenotype, especially nephritis, and to investigate the relation between this polymorphism and clinical data, treatment outcome, serum level of C1q protein and antibodies. Typing of C1q rs292001 polymorphism using restriction fragment length polymorphism and measuring serum levels of C1q protein and antibodies by enzyme-linked immunosorbent assay (ELISA) were performed for 130 children with SLE and 208 healthy controls. The A allele of C1q rs292001 was associated with jSLE and LN (P = 0·005 and 0·013, respectively) and the AA genotype was associated with jSLE (P = 0·036). Low serum levels of C1q protein were found in jSLE and LN (P < 0·001 and 0·009, respectively), and these levels were increased after treatment in patients with LN (P = 0·009) and active renal disease (P = 0·027). Higher titres of C1q antibodies were found in patients with LN (P = 0·015) and correlated negatively with C1q protein level (P < 0·001) and patient age (P = 0·04). The A allele and AA genotype of C1q rs292001 can be considered a susceptibility risk factor and the GG genotype could be considered protective for jSLE and LN in the studied cohort of Egyptian children. Decreased serum levels of C1q protein and increased titres of C1q antibodies may be involved in the pathogenesis of jSLE, especially LN.
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Affiliation(s)
- Y M Mosaad
- Clinical Immunology Unit, Clinical Pathology Department and Mansoura Research Center for Cord Stem Cells (MARC_CSC), Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - A Hammad
- Pediatric Nephrology Unit, Mansoura University Children's Hospital, Mansoura, Egypt
| | - Z Fawzy
- Clinical Immunology Unit, Clinical Pathology Department and Mansoura Research Center for Cord Stem Cells (MARC_CSC), Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - A El-Refaaey
- Pediatric Nephrology Unit, Mansoura University Children's Hospital, Mansoura, Egypt
| | - Z Tawhid
- Clinical Immunology Unit, Clinical Pathology Department and Mansoura Research Center for Cord Stem Cells (MARC_CSC), Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - E M Hammad
- Rheumatology and Rehabilitation Department, Mansoura University Hospital, Mansoura, Egypt
| | - L F Youssef
- Department of Biochemistry, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt
| | - E A A ElAttar
- Pediatric Department, Mansoura General Hospital, Mansoura, Egypt
| | - D F Radwan
- Blood Bank, Central Talkha Hospital, Mansoura, Egypt
| | - I M Fawzy
- Laboratory Medicine Department, Mansoura Fever Hospital, Ministry of Health, Mansoura, Egypt
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Haddon DJ, Diep VK, Price JV, Limb C, Utz PJ, Balboni I. Autoantigen microarrays reveal autoantibodies associated with proliferative nephritis and active disease in pediatric systemic lupus erythematosus. Arthritis Res Ther 2015; 17:162. [PMID: 26081107 PMCID: PMC4493823 DOI: 10.1186/s13075-015-0682-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 06/11/2015] [Indexed: 12/31/2022] Open
Abstract
Introduction Pediatric systemic lupus erythematosus (pSLE) patients often initially present with more active and severe disease than adults, including a higher frequency of lupus nephritis. Specific autoantibodies, including anti-C1q, anti-DNA and anti-alpha-actinin, have been associated with kidney involvement in SLE, and DNA antibodies are capable of initiating early-stage lupus nephritis in severe combined immunodeficiency (SCID) mice. Over 100 different autoantibodies have been described in SLE patients, highlighting the need for comprehensive autoantibody profiling. Knowledge of the antibodies associated with pSLE and proliferative nephritis will increase the understanding of SLE pathogenesis, and may aid in monitoring patients for renal flare. Methods We used autoantigen microarrays composed of 140 recombinant or purified antigens to compare the serum autoantibody profiles of new-onset pSLE patients (n = 45) to healthy controls (n = 17). We also compared pSLE patients with biopsy-confirmed class III or IV proliferative nephritis (n = 23) and without significant renal involvement (n = 18). We performed ELISA with selected autoantigens to validate the microarray findings. We created a multiple logistic regression model, based on the ELISA and clinical information, to predict whether a patient had proliferative nephritis, and used a validation cohort (n = 23) and longitudinal samples (88 patient visits) to test its accuracy. Results Fifty autoantibodies were at significantly higher levels in the sera of pSLE patients compared to healthy controls, including anti-B cell-activating factor (BAFF). High levels of anti-BAFF were associated with active disease. Thirteen serum autoantibodies were present at significantly higher levels in pSLE patients with proliferative nephritis than those without, and we confirmed five autoantigens (dsDNA, C1q, collagens IV and X and aggrecan) by ELISA. Our model, based on ELISA measurements and clinical variables, correctly identified patients with proliferative nephritis with 91 % accuracy. Conclusions Autoantigen microarrays are an ideal platform for identifying autoantibodies associated with both pSLE and specific clinical manifestations of pSLE. Using multiple regression analysis to integrate autoantibody and clinical data permits accurate prediction of clinical manifestations with complex etiologies in pSLE. Electronic supplementary material The online version of this article (doi:10.1186/s13075-015-0682-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- D James Haddon
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University School of Medicine, 291 Campus Drive, Stanford, CA, 94305, USA.
| | - Vivian K Diep
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University School of Medicine, 291 Campus Drive, Stanford, CA, 94305, USA.
| | - Jordan V Price
- Department of Molecular and Cell Biology, Division of Immunology and Pathogenesis, University of California at Berkeley, 142 Life Sciences Addition #3200, Berkeley, CA, 94720, USA.
| | - Cindy Limb
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University School of Medicine, 291 Campus Drive, Stanford, CA, 94305, USA.
| | - Paul J Utz
- Department of Medicine, Division of Immunology and Rheumatology, Stanford University School of Medicine, 291 Campus Drive, Stanford, CA, 94305, USA.
| | - Imelda Balboni
- Department of Pediatrics, Division of Allergy, Immunology and Rheumatology, Stanford University School of Medicine, 291 Campus Drive, Stanford, CA, 94305, USA.
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Beurskens FJ, van Schaarenburg RA, Trouw LA. C1q, antibodies and anti-C1q autoantibodies. Mol Immunol 2015; 68:6-13. [PMID: 26032012 DOI: 10.1016/j.molimm.2015.05.010] [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] [Revised: 05/04/2015] [Accepted: 05/07/2015] [Indexed: 12/21/2022]
Abstract
The complement system has long been known for its role in combating infections. More recently the complement system is becoming increasingly appreciated for its role in processes that range from waste transport, immune tolerance and shaping of the adaptive immune response. Antibodies represent the humoral part of the adaptive immune response and the complement system interacts with antibodies in several ways. Activated complement fragments impact on the production of antibodies, the complement system gets activated by antibodies and complement proteins can be the target of (auto)antibodies. In this review, written to celebrate the contributions of Prof. Dr. M.R. Daha to the field of immunology and especially complement, we will focus on C1q and its various interactions with antibodies. We will specifically focus on the mechanisms by which C1q will interact with monomeric IgG versus polymerized IgG and fluid-phase IgM versus solid-phase IgM. In addition in this review we will discuss in detail how C1q itself is targeted by autoantibodies and how these autoantibodies are currently considered to play a role in human disease.
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Affiliation(s)
| | | | - Leendert A Trouw
- Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.
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Merle NS, Noe R, Halbwachs-Mecarelli L, Fremeaux-Bacchi V, Roumenina LT. Complement System Part II: Role in Immunity. Front Immunol 2015; 6:257. [PMID: 26074922 PMCID: PMC4443744 DOI: 10.3389/fimmu.2015.00257] [Citation(s) in RCA: 632] [Impact Index Per Article: 70.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 05/09/2015] [Indexed: 12/14/2022] Open
Abstract
The complement system has been considered for a long time as a simple lytic cascade, aimed to kill bacteria infecting the host organism. Nowadays, this vision has changed and it is well accepted that complement is a complex innate immune surveillance system, playing a key role in host homeostasis, inflammation, and in the defense against pathogens. This review discusses recent advances in the understanding of the role of complement in physiology and pathology. It starts with a description of complement contribution to the normal physiology (homeostasis) of a healthy organism, including the silent clearance of apoptotic cells and maintenance of cell survival. In pathology, complement can be a friend or a foe. It acts as a friend in the defense against pathogens, by inducing opsonization and a direct killing by C5b–9 membrane attack complex and by triggering inflammatory responses with the anaphylatoxins C3a and C5a. Opsonization plays also a major role in the mounting of an adaptive immune response, involving antigen presenting cells, T-, and B-lymphocytes. Nevertheless, it can be also an enemy, when pathogens hijack complement regulators to protect themselves from the immune system. Inadequate complement activation becomes a disease cause, as in atypical hemolytic uremic syndrome, C3 glomerulopathies, and systemic lupus erythematosus. Age-related macular degeneration and cancer will be described as examples showing that complement contributes to a large variety of conditions, far exceeding the classical examples of diseases associated with complement deficiencies. Finally, we discuss complement as a therapeutic target.
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Affiliation(s)
- Nicolas S Merle
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France
| | - Remi Noe
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France ; Ecole Pratique des Hautes Études (EPHE) , Paris , France
| | - Lise Halbwachs-Mecarelli
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France
| | - Veronique Fremeaux-Bacchi
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France ; Service d'Immunologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou , Paris , France
| | - Lubka T Roumenina
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France
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The value of a panel of autoantibodies for predicting the activity of lupus nephritis at time of renal biopsy. J Immunol Res 2015; 2015:106904. [PMID: 25815344 PMCID: PMC4357044 DOI: 10.1155/2015/106904] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 02/16/2015] [Indexed: 11/23/2022] Open
Abstract
Few studies have correlated serum biomarkers with renal histology, the gold standard for renal activity, in lupus nephritis (LN). We tested a panel of autoantibodies and complement at the time of kidney biopsy and after treatment. Anti-dsDNA, anti-nucleosome, anti-ribosome P, and anti-C1q antibodies and C3/C4 were measured in 107 patients with LN at the time of renal biopsy and after 6–12 months and were correlated with clinical/histological parameters. At multivariate analysis, high titers of anti-C1q antibodies or of anti-dsDNA antibodies (P = 0.005, OR = 8.67, CI: 2.03–37.3) were the independent predictors that discriminate proliferative from nonproliferative LN. All the immunological parameters, except anti-ribosome, showed a significant correlation with activity index but not with chronicity index. Only anti-C1q showed a significant correlation with the amount of proteinuria (R = 0.2, P = 0.03). None of the immunological parameters were predictive of remission at 6 and 12 months. We found that anti-C1q alone or in combination with anti-dsDNA emerged as the most reliable test in differentiating proliferative and nonproliferative LN. Anti-C1q was the only test correlated with the clinical presentation of LN. After treatment, the titre of the autoantibodies was significantly reduced, but none was predictive of remission.
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Abstract
Antigen-antibody complexes in tissues play a central role in the pathogenesis of lupus. Some of the immune complexes are formed in situ, i.e., in the tissues. Others are present in the blood stream, and these circulating immune complexes may deposit in tissues and incite inflammatory mechanisms in those tissues. A variety of techniques are available to measure circulating immune complexes. The assays that have been most studied in SLE include approaches that rely on the interaction of immune complexes with complement proteins, and therefore bind to C1q or contain bound C3. In the process of investigating circulating immune complexes, it was recognized that lupus patients generate serum autoantibodies directed against C1q and other complement proteins. Antibodies reacting with the collagen-like region of C1q are known to be closely linked both clinically and pathophysiologically to lupus nephritis. This chapter describes methods for detection of C1q-binding immune complexes via the C1q solid-phase assay and the related test for autoantibodies to C1q.
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Affiliation(s)
- Mark H Wener
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA
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Leffler J, Bengtsson AA, Blom AM. The complement system in systemic lupus erythematosus: an update. Ann Rheum Dis 2014; 73:1601-6. [PMID: 24845390 DOI: 10.1136/annrheumdis-2014-205287] [Citation(s) in RCA: 170] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The complement system plays a major role in the autoimmune disease, systemic lupus erythematosus (SLE). However, the role of complement in SLE is complex since it may both prevent and exacerbate the disease. In this review, we explore the latest findings in complement-focused research in SLE. C1q deficiency is the strongest genetic risk factor for SLE, although such deficiency is very rare. Various recently discovered genetic associations include mutations in the complement receptors 2 and 3 as well as complement inhibitors, the latter related to earlier onset of nephritis. Further, autoantibodies are a distinct feature of SLE that are produced as the result of an adaptive immune response and how complement can affect that response is also being reviewed. SLE generates numerous disease manifestations involving contributions from complement such as glomerulonephritis and the increased risk of thrombosis. Furthermore, since most of the complement system is present in plasma, complement is very accessible and may be suitable as biomarker for diagnosis or monitoring of disease activity. This review highlights the many roles of complement for SLE pathogenesis and how research has progressed during recent years.
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Affiliation(s)
- Jonatan Leffler
- Division of Medical Protein Chemistry, Department of Laboratory Medicine Malmö, Lund University, Malmö, Sweden Division of Cell Biology and Immunology, Telethon Kids Institute, University of Western Australia, Subiaco, Australia
| | - Anders A Bengtsson
- Department of Clinical Sciences, Section of Rheumatology, Lund University, Skåne University Hospital Lund, Lund, Sweden
| | - Anna M Blom
- Division of Medical Protein Chemistry, Department of Laboratory Medicine Malmö, Lund University, Malmö, Sweden
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44
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Focosi D, De Donno M, Pratesi F. Endogenous anti-C1q antibodies do not interfere with the C1qScreen™ assay. ACTA ACUST UNITED AC 2014; 83:356-7. [PMID: 24649862 DOI: 10.1111/tan.12339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 02/20/2014] [Indexed: 11/28/2022]
Affiliation(s)
- D Focosi
- Department of Translational Research, University of Pisa, Pisa, Italy
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The Usefulness of Endothelial Cell Adhesion Molecules and Anti-C1q Antibody in Monitoring Systemic Lupus Erythematosus Disease Activity. INTERNATIONAL SCHOLARLY RESEARCH NOTICES 2014; 2014:275194. [PMID: 27355017 PMCID: PMC4897568 DOI: 10.1155/2014/275194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 08/04/2014] [Accepted: 08/04/2014] [Indexed: 11/18/2022]
Abstract
Objectives. The study was conducted to determine the correlation of ICAM-1, VCAM-1, and anti-C1q antibody levels with SLE disease activity index (SLEDAI) and standard SLE disease activity immunological markers (anti-dsDNA and sera C3 and C4). Study Design. This was a cross-sectional study. Materials and Methods. Blood samples were obtained from 95 SLE patients (45 active SLE and 50 nonactive SLE) and 50 controls. The subjects were assessed using SLEDAI and score of more than five is determined as having active SLE. The sera were tested for serum ICAM-1, VCAM-1, and anti-C1q (ELISA), anti-dsDNA (CLIFT), serum C3, and serum C4 (immunonephelometry). Results. Anti-dsDNA and anti-C1q antibody showed good positive correlations with SLEDAI (r = 0.529, P < 0.001 and r = 0.559, P < 0.001, resp.). VCAM-1 and sera C3 and C4 showed fair correlation with SLEDAI (r = 0.294, P = 0.004; r = −0.312, P = 0.002; and r = −0.382, P < 0.001, resp.). ICAM-1 level showed no significant correlation with SLEDAI (P = 0.062). There were significant correlations of VCAM-1 and anti-C1q antibody with anti-dsDNA (r = 0.226, P = 0.006 and r = 0.511, P < 0.001, resp.). VCAM-1 showed poor inverse correlation with serum C3 (r = −0.183, P = 0.028) and fair inverse correlation with serum C4 (r = −0.251, P = 0.002). Anti-C1q antibody demonstrated fair inverse correlation with both sera C3 and C4 (r = −0.420, P ≤ 0.001 and r = −0.398, P < 0.001, resp.). However, ICAM-1 showed no significant correlation with anti-dsDNA and sera C3 and C4 (P = 0.259, P = 0.626 and P = 0.338, resp.). Conclusions. The serum levels of anti-C1q antibody in SLE patients showed the best correlation with the SLEDAI and standard immunological tests for SLE disease activity. These data support that anti-C1q antibody is a useful marker for monitoring SLE global disease activity. The potential of VCAM-1 needs further confirmation.
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Abstract
The recently concluded Tenth International Congress on Systemic Lupus Erythematosus (SLE) held in Buenos Aires was a resounding success. This overview summarizes some of the origins of the First International Congress held in Calgary, Canada in 1986, predictions offered by past Congress Presidents, and a perspective on the trends in autoantibody testing, which remains one of the key approaches to the early and accurate diagnosis of SLE. The last few decades have witnessed a remarkable proliferation of new diagnostic technologies including addressable laser bead immunoassays and, more recently, chemiluminescence and lateral flow technologies that could find a clinical niche in point-of-care diagnostics. Against the backdrop of these constantly emerging technologies, indirect immunofluorescence has remained the platform of choice for many laboratories and diagnosticians. The notion that autoantibodies are pathogenic has been challenged by evidence that some autoantibodies are protective, some may have catalytic capacity while others may be neutral or have no function at all. The latter notion of functionless or "junk" autoantibodies needs to be taken under some advisement, because there was a time when a great proportion of the human genome was considered to include "junk DNA". The butterfly as a symbol of hope and progress in SLE research over the past 27 years since the First International Congress on SLE is almost certainly to be even more appropriate when future Congresses are held in Geneva (2015), Melbourne (2017) and eventually one in 2050.
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