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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: 30] [Impact Index Per Article: 30.0] [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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Savelli SL, Roubey RAS, Kitzmiller KJ, Zhou D, Nagaraja HN, Mulvihill E, Barbar-Smiley F, Ardoin SP, Wu YL, Yu CY. Opposite Profiles of Complement in Antiphospholipid Syndrome (APS) and Systemic Lupus Erythematosus (SLE) Among Patients With Antiphospholipid Antibodies (aPL). Front Immunol 2019; 10:885. [PMID: 31134052 PMCID: PMC6514053 DOI: 10.3389/fimmu.2019.00885] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 04/05/2019] [Indexed: 12/18/2022] Open
Abstract
APS is the association of antiphospholipid antibodies (aPL) with thromboses and/or recurrent pregnancy loss (RPL). Among patients with SLE, one-third have aPL and 10–15% have a manifestation of secondary APS. Animal studies suggested that complement activation plays an important role in the pathogenesis of thrombosis and pregnancy loss in APS. We performed a cross-sectional study on complement proteins and genes in 525 patients with aPL. Among them, 237 experienced thromboses and 293 had SLE; 111 had both SLE and thromboses, and 106 had neither SLE nor thrombosis. Complement protein levels were determined by radial immunodiffusion for C4, C3 and factor H; and by functional ELISA for mannan binding lectin (MBL). Total C4, C4A and C4B gene copy numbers (GCN) were measured by TaqMan-based realtime PCR. Two to six copies of C4 genes are frequently present in a diploid genome, and each copy may code for an acidic C4A or a basic C4B protein. We observed significantly (a) higher protein levels of total C4, C4A, C4B, C3, and anticardiolipin (ACLA) IgG, (b) increased frequencies of lupus anticoagulant and males, and (c) decreased levels of complement factor H, MBL and ACLA-IgM among patients with thrombosis than those without thrombosis (N = 288). We also observed significantly lower GCNs of total C4 and C4A among aPL-positive patients with both SLE and thrombosis than others. By contrast, aPL-positive subjects with SLE had significantly reduced protein levels of C3, total C4, C4A, C4B and ACLA-IgG, and higher frequency of females than those without SLE. Patients with thrombosis but without SLE (N = 126), and patients with SLE but without thrombosis (N = 182) had the greatest differences in mean protein levels of C3 (p = 2.6 × 10−6), C4 (p = 2.2 × 10−9) and ACLA-IgG (p = 1.2 × 10−5). RPL occurred in 23.7% of female patients and thrombotic SLE patients had the highest frequency of RPL (41.0%; p = 3.8 × 10−10). Compared with non-RPL females, RPL had significantly higher frequency of thrombosis and elevated C4 protein levels. Female patients with homozygous C4A deficiency all experienced RPL (p = 0.0001) but the opposite was true for patients with homozygous C4B deficiency (p = 0.017). These results provide new insights and biomarkers for diagnosis and management of APS and SLE.
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Affiliation(s)
- Stephanie L Savelli
- The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Division of Hematology/Oncology, Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Robert A S Roubey
- Division of Rheumatology, Allergy and Immunology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kathryn J Kitzmiller
- The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Danlei Zhou
- The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States.,Division of Rheumatology, Nationwide Children's Hospital, Columbus, OH, United States
| | - Haikady N Nagaraja
- Division of Biostatistics, College of Public Health, The Ohio State University, Columbus, OH, United States
| | - Evan Mulvihill
- Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States.,Division of Rheumatology, Nationwide Children's Hospital, Columbus, OH, United States
| | - Fatima Barbar-Smiley
- Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States.,Division of Rheumatology, Nationwide Children's Hospital, Columbus, OH, United States
| | - Stacy P Ardoin
- Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States.,Division of Rheumatology, Nationwide Children's Hospital, Columbus, OH, United States
| | - Yee Ling Wu
- The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States.,Department of Microbiology and Immunology, Loyola University Chicago, Maywood, IL, United States
| | - Chack-Yung Yu
- The Research Institute at Nationwide Children's Hospital, Columbus, OH, United States.,Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States.,Division of Rheumatology, Nationwide Children's Hospital, Columbus, OH, United States
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Mahajan SD, Tutino VM, Redae Y, Meng H, Siddiqui A, Woodruff TM, Jarvis JN, Hennon T, Schwartz S, Quigg RJ, Alexander JJ. C5a induces caspase-dependent apoptosis in brain vascular endothelial cells in experimental lupus. Immunology 2016; 148:407-19. [PMID: 27213693 DOI: 10.1111/imm.12619] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 05/06/2016] [Accepted: 05/10/2016] [Indexed: 12/18/2022] Open
Abstract
Blood-brain barrier (BBB) dysfunction complicates central nervous system lupus, an important aspect of systemic lupus erythematosus. To gain insight into the underlying mechanism, vascular corrosion casts of brain were generated from the lupus mouse model, MRL/lpr mice and the MRL/MpJ congenic controls. Scanning electron microscopy of the casts showed loss of vascular endothelial cells in lupus mice compared with controls. Immunostaining revealed a significant increase in caspase 3 expression in the brain vascular endothelial cells, which suggests that apoptosis could be an important mechanism causing cell loss, and thereby loss of BBB integrity. Complement activation occurs in lupus resulting in increased generation of circulating C5a, which caused the endothelial layer to become 'leaky'. In this study, we show that C5a and lupus serum induced apoptosis in cultured human brain microvascular endothelial cells (HBMVECs), whereas selective C5a receptor 1 (C5aR1) antagonist reduced apoptosis in these cells, demonstrating C5a/C5aR1-dependence. Gene expression of initiator caspases, caspase 1 and caspase 8, and pro-apoptotic proteins death-associated protein kinase 1, Fas-associated protein (FADD), cell death-inducing DNA fragmentation factor 45 000 MW subunit A-like effector B (CIDEB) and BCL2-associated X protein were increased in HBMVECs treated with lupus serum or C5a, indicating that both the intrinsic and extrinsic apoptotic pathways could be critical mediators of brain endothelial cell apoptosis in this setting. Overall, our findings suggest that C5a/C5aR1 signalling induces apoptosis through activation of FADD, caspase 8/3 and CIDEB in brain endothelial cells in lupus. Further elucidation of the underlying apoptotic mechanisms mediating the reduced endothelial cell number is important in establishing the potential therapeutic effectiveness of C5aR1 inhibition that could prevent and/or reduce BBB alterations and preserve the physiological function of BBB in central nervous system lupus.
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Affiliation(s)
| | - Vincent M Tutino
- Toshiba Vascular Stroke Center, Biomedical Engineering Department, University at Buffalo, Buffalo, NY, USA
| | - Yonas Redae
- Department of Medicine, University at Buffalo, Buffalo, NY, USA
| | - Hui Meng
- Toshiba Vascular Stroke Center, Biomedical Engineering Department, University at Buffalo, Buffalo, NY, USA
| | - Adnan Siddiqui
- Toshiba Vascular Stroke Center, Biomedical Engineering Department, University at Buffalo, Buffalo, NY, USA
| | - Trent M Woodruff
- School of Biomedical Sciences, University of Queensland, St Lucia, QLD, Australia
| | - James N Jarvis
- Department of Pediatrics, University at Buffalo, Buffalo, NY, USA
| | - Teresa Hennon
- Department of Pediatrics, University at Buffalo, Buffalo, NY, USA
| | | | - Richard J Quigg
- Department of Medicine, University at Buffalo, Buffalo, NY, USA
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4
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Artemisinins and immune system. Eur J Pharmacol 2011; 668:6-14. [PMID: 21756901 DOI: 10.1016/j.ejphar.2011.06.044] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 06/13/2011] [Accepted: 06/22/2011] [Indexed: 01/26/2023]
Abstract
Artemisinins in combination with other antimalarial drugs remain the mainstay of current antimalarial armamentarium. It is interesting to note that many traditional drugs with antiprotozoal background can wield immunomodulation on the recipient's immune system in a positive or negative direction. Artemisinins also attribute immunomodulatory distensions. For instance, they demonstrate predominant immunosuppressive traits toward different immune components by particularly regulating the cellular proliferation and cytokine release, which indicates that they possess some additional mechanisms and features demanding deliberate attentions. This article reviews the data-based immunomodulatory effects of artemisinins on different immune cells including neutrophils, macrophages, splenocytes, T and B cells in conjunction with their therapeutic prospective with regard to inflammation, autoimmunity and delayed-type hypersensitivity.
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Wang G, Ujiie H, Shibaki A, Nishie W, Tateishi Y, Kikuchi K, Li Q, McMillan JR, Morioka H, Sawamura D, Nakamura H, Shimizu H. Blockade of autoantibody-initiated tissue damage by using recombinant fab antibody fragments against pathogenic autoantigen. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 176:914-25. [PMID: 20042683 DOI: 10.2353/ajpath.2010.090744] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Activation of the complement cascade via the classical pathway is required for the development of tissue injury in many autoantibody-mediated diseases. It therefore makes sense to block the pathological action of autoantibodies by preventing complement activation through inhibition of autoantibody binding to the corresponding pathogenic autoantigen using targeted Fab antibody fragments. To achieve this, we use bullous pemphigoid (BP) as an example of a typical autoimmune disease. Recombinant Fabs against the non-collagenous 16th-A domain of type XVII collagen, the main pathogenic epitope for autoantibodies in BP, were generated from antibody repertoires of BP patients by phage display. Two Fabs, Fab-B4 and Fab-19, showed marked ability to inhibit the binding of BP autoantibodies and subsequent complement activation in vitro. In the in vivo experiments using type XVII collagen humanized BP model mice, these Fabs protected mice against BP autoantibody-induced blistering disease. Thus, the blocking of pathogenic epitopes using engineered Fabs appears to demonstrate efficacy and may lead to disease-specific treatments for antibody-mediated autoimmune diseases.
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Affiliation(s)
- Gang Wang
- Department of Dermatology, Hokkaido University Graduate School of Medicine, N15 W7, Sapporo, 060-8638 Japan
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López-Lera A, Garrido S, de la Cruz RM, Fontán G, López-Trascasa M. Molecular characterization of three new mutations causing C5 deficiency in two non-related families. Mol Immunol 2009; 46:2340-7. [PMID: 19414197 DOI: 10.1016/j.molimm.2009.03.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 03/27/2009] [Accepted: 03/27/2009] [Indexed: 11/19/2022]
Abstract
Deficiencies in complement components are rare diseases whose diagnosis is often underestimated. In addition, in only a few cases molecular studies have been carried out for the characterization of the underlying genetic defects. To date, studies involving C5-deficient patients are scarce. The aim of the present report is to characterize the biochemical and molecular complement deficiency in two non-related families with one or more members showing no detectable hemolytic complement activity (CH50<50 U/ml) and reporting a history of several episodes of meningitis. Protein deficiency was assessed by means of hemolytic assays, bi-dimensional double immunodiffusion, ELISA and Western blot of patients' sera. Molecular studies were carried out by PCR and RT-PCR of DNA and RNA, respectively, both extracted from fresh blood samples of each family member. In Family A, only the propositus had complete C5 deficiency. Molecular studies showed that he was heterozygous for two changes in the C5 gene. One of the mutations was also carried by the father (c.1883_1884AG<CTCT) and the second (c.2536T>C, Y846H) was a de novo mutation. In Family B, the two C5-deficient members share the homozygous nonsense mutation c.892C>T (Q298X) in exon 9. The characterization of these new mutations is interesting in order to elucidate structure-function relationships in the C5 gene and it also helps to understand the molecular basis of this uncommon deficiency. Moreover, this report highlights the importance of complement screening in cases of repeated meningococcal infections in order to establish its involvement and to consider adequate clinical recommendations such as prophylactic antibiotics or meningococcal vaccines.
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Affiliation(s)
- Alberto López-Lera
- Unidad de Inmunología, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) U 754, Hospital Universitario La Paz, Paseo de la Castellana, 261, 28046 Madrid, Spain
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Mejri K, Mbarek H, Kallel-Sellami M, Petit-Teixeira E, Zerzeri Y, Abida O, Zitouni M, Ben Ayed M, Mokni M, Fezza B, Turki H, Tron F, Gilbert D, Masmoudi H, Prum B, Cornelis F, Makni S. TRAF1/C5 polymorphism is not associated with pemphigus. Br J Dermatol 2009; 160:1348-50. [PMID: 19416238 DOI: 10.1111/j.1365-2133.2009.09136.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Weiler H. Tracing the molecular pathogenesis of antiphospholipid syndrome. J Clin Invest 2008; 118:3276-8. [PMID: 18802489 DOI: 10.1172/jci37243] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Fetal loss induced by antiphospholipid antibodies (aPLs) in mice is a complement-driven inflammatory condition. Engagement of the complement receptor C5aR on neutrophils induces expression of the principal initiator of the blood clotting mechanism, tissue factor (TF), and blocking this downstream event of complement activation prevents antibody-induced fetal loss. In this issue of the JCI, the study by Redecha et al. clarifies that in mice, the contribution of TF to this pathogenic mechanism is independent of its role in coagulation and thrombosis, but involves inflammatory signaling through the receptor PAR2 (see the related article beginning on page 3453). The study not only sheds light on a critical effector mechanism of aPL-induced fetal loss, but also suggests that treatment with statins, which decrease TF and PAR2 expression, may hold promise as a therapeutic approach to antiphospholipid syndrome-associated pregnancy complications.
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Affiliation(s)
- Hartmut Weiler
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, Wisconsin, USA
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Abstract
Alternative pathway amplification plays a major role for the final effect of initial specific activation of the classical and lectin complement pathways, but the quantitative role of the amplification is insufficiently investigated. In experimental models of human diseases in which a direct activation of alternative pathway has been assumed, this interpretation needs revision placing a greater role on alternative amplification. We recently documented that the alternative amplification contributed to 80–90% of C5 activation when the initial activation was highly specific for the classical pathway. The recent identification of properdin as a recognition factor directly initiating alternative pathway activation, like C1q in the classical and mannose-binding lectin in the lectin pathway, initiates a renewed interest in the reaction mechanisms of complement. Complement and Toll-like receptors, including the CD14 molecule, are two main upstream recognition systems of innate immunity, contributing to the inflammatory reaction in a number of conditions including ischaemia-reperfusion injury and sepsis. These systems act as ‘double-edged swords’, being protective against microbial invasion, but harmful to the host when activated improperly or uncontrolled. Combined inhibition of complement and Toll-like receptors/CD14 should be explored as a treatment regimen to reduce the overwhelming damaging inflammatory response during sepsis. The alternative pathway should be particularly considered in this regard, due to its uncontrolled amplification in sepsis. The alternative pathway should be regarded as a dual system, namely a recognition pathway principally similar to the classical and lectin pathways, and an amplification mechanism, well known, but quantitatively probably more important than generally recognized.
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Affiliation(s)
- Morten Harboe
- Institute of Immunology, University of Oslo and Rikshospitalet University Hospital, Oslo, Norway
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Licht C, Heinen S, Józsi M, Löschmann I, Saunders RE, Perkins SJ, Waldherr R, Skerka C, Kirschfink M, Hoppe B, Zipfel PF. Deletion of Lys224 in regulatory domain 4 of Factor H reveals a novel pathomechanism for dense deposit disease (MPGN II). Kidney Int 2006; 70:42-50. [PMID: 16612335 DOI: 10.1038/sj.ki.5000269] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We report a novel pathomechanism for membranoproliferative glomerulonephritis type II (MPGN II) caused by a mutant Factor H protein expressed in the plasma. Genetic analyses of two patients revealed deletion of a single Lys residue (K224) located within the complement regulatory region in domain 4 of Factor H. This deletion resulted in defective complement control: mutant protein purified from the plasma of patients showed severely reduced cofactor and decay-accelerating activity, as well as reduced binding to the central complement component C3b. However, cell-binding activity of the mutant protein was normal and comparable to wild-type Factor H. The patients are daughters of consanguineous parents. As both patients but also their healthy mother were positive for C3 nephritic factor, the mutant Factor H protein is considered relevant for unrestricted activation of the disease-causing activation of the alternative complement pathway. Replacement of functional Factor H by fresh frozen plasma (10-15 ml/kg/14 days) was well tolerated, prevented so far disease progression in both patients, and is in the long run expected to preserve kidney function.
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Affiliation(s)
- C Licht
- Children's Hospital of the University of Cologne, Pediatric Nephrology, Cologne, Germany
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Modifications de la réponse immune durant la grossesse : implications dans la polyarthrite rhumatoïde et le lupus systémique. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.rhum.2005.02.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Harboe M, Ulvund G, Vien L, Fung M, Mollnes TE. The quantitative role of alternative pathway amplification in classical pathway induced terminal complement activation. Clin Exp Immunol 2005; 138:439-46. [PMID: 15544620 PMCID: PMC1809239 DOI: 10.1111/j.1365-2249.2004.02627.x] [Citation(s) in RCA: 237] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Complement activation with formation of biologically potent mediators like C5a and the terminal C5b-9 complex (TCC) contributes essentially to development of inflammation and tissue damage in a number of autoimmune and inflammatory conditions. A particular role for complement in the ischaemia/reperfusion injury of the heart, skeletal muscle, central nervous system, intestine and kidney has been suggested from animal studies. Previous experiments in C3 and C4 knockout mice suggested an important role of the classical or lectin pathway in initiation of complement activation during intestinal ischaemia/reperfusion injury while later use of factor D knockout mice showed the alternative pathway to be critically involved. We hypothesized that alternative pathway amplification might play a more critical role in classical pathway-induced C5 activation than previously recognized and used pathway-selective inhibitory mAbs to further elucidate the role of the alternative pathway. Here we demonstrate that selective blockade of the alternative pathway by neutralizing factor D in human serum diluted 1 : 2 with mAb 166-32 inhibited more than 80% of C5a and TCC formation induced by solid phase IgM and solid- and fluid-phase human aggregated IgG via the classical pathway. The findings emphasize the influence of alternative pathway amplification on the effect of initial classical pathway activation and the therapeutic potential of inhibiting the alternative pathway in clinical conditions with excessive and uncontrolled complement activation.
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Affiliation(s)
- M Harboe
- Institute of Immunology, Rikshospitalet University Hospital, NO-0027 Oslo, Norway
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Delgado-Cerviño E, Fontán G, López-Trascasa M. C5 complement deficiency in a Spanish family. Molecular characterization of the double mutation responsible for the defect. Mol Immunol 2005; 42:105-11. [PMID: 15488949 DOI: 10.1016/j.molimm.2004.06.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2004] [Accepted: 06/11/2004] [Indexed: 10/26/2022]
Abstract
The complement C5 deficiency is a recessive autosomal defect associated with recurrent infectious episodes, generally caused by Gram-negative micro-organisms. To date, only two mutations responsible for C5 deficiency have been characterized, both in heterozygosis. In this paper, we evaluate by immunochemical methods the C5 deficiency in a six-member family, in which one member suffered from meningococcal sepsis and several pneumonia episodes; and a second one with two bacterial meningitis episodes and frequent tonsillitis, pneumonia and herpetic episodes. We also characterize the molecular basis of this deficiency. No C5 protein was found in the serum from three of the children. They were found to be homozygous for a double mutation in the exon 40 of the C5 gene. The parents and the other children have half-normal levels of C5, and they were heterozygotes for the double mutation. This mutation modifies the reading frame, leading to a premature stop codon, and the resulting protein lacks 50 amino acids. As a result, homozygotes and heterozygotes have a total or a partial C5 deficiency respectively. This is the first report of a whole molecular characterization of C5 deficiency.
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Affiliation(s)
- Eva Delgado-Cerviño
- Unit of Immunology, Hospital Universitario La Paz, Paseo de la Castellana 261, 28046 Madrid, Spain
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