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Lupus nephritis with corticosteroid responsiveness: molecular changes of CD46-mediated type 1 regulatory T cells. Pediatr Res 2022; 92:1099-1107. [PMID: 34952938 DOI: 10.1038/s41390-021-01882-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 11/05/2021] [Accepted: 11/11/2021] [Indexed: 12/28/2022]
Abstract
BACKGROUND The engagement of the complement regulatory proteins CD46 and CD3 in human CD4+ T cells induces the type 1 regulatory T cells (Tr1) and interleukin-10 (IL-10) secretion. This study aimed to elucidate the molecular changes of Tr1 cells through CD46 cytoplasmic Cyt1 tail in lupus nephritis (LN) respond to intravenous methylprednisolone (ivMP) therapy. METHODS We enrolled 40 pediatric patients with LN and 30 healthy controls. Clinical characteristics and peripheral blood mononuclear cells were collected before and 3 days after the administration of ivMP. Kidney specimens were taken from five LN and five minimal-change nephrotic syndrome patients. RESULTS We found that defective CD46-mediated T-helper type 1 contraction (IL-10 switching) is present in active LN patients. The ivMP therapy enhanced LN remission, restored the production of IL-10, increased the CD46-Cyt1/Cyt2 ratio, AKT, and cAMP-responsive element-binding protein phosphorylation, and induced migration with the expression of chemokine receptor molecules CCR4, CCR6, and CCR7 of CD3/CD46-activated Tr1 cells. CONCLUSIONS Pharmacologic interventions that alter the patterns of CD46-Cyt1/Cyt2 expression and the secretion of IL-10 by CD3/CD46-activated Tr1 cells can be used in patients with active LN. IMPACT In patients with LN, ivMP was associated with increased IL-10 production and increased CD46-Cyt1/Cyt2 ratio and AKT phosphorylation by Tr1 cells, with enhanced potential to migration in response to CCL17. These results suggest that expression levels of CD46 isoforms Cyt1 and Cyt2 in CD4 + CD46 + Tr1 cells differ in patients with active LN but can be corrected by corticosteroid treatment. Enhancing the expression of functional CD4 + CD46 + Tr1 cells may be a useful therapeutic approach for LN.
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2
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Evaluating the clinical utility of measuring levels of factor H and the related proteins. Mol Immunol 2022; 151:166-182. [PMID: 36162225 DOI: 10.1016/j.molimm.2022.08.010] [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: 05/09/2022] [Revised: 08/04/2022] [Accepted: 08/15/2022] [Indexed: 11/21/2022]
Abstract
After years of disappointing clinical results, the tide has finally changed and complement targeted-therapies have become a validated and accepted treatment option for several diseases. These accomplishments have revitalized the field and brought renewed attention to the prospects that complement therapeutics can offer. Streamlining diagnostics and therapeutics is imperative in this new era of clinical use of complement therapeutics. However, the incredible success in therapeutics has not been accompanied by the development of novel standardized tools for complement testing. Complement biomarkers can assist in the risk assessment and diagnosis of diseases as well as the prediction of disease progression and treatment response. Recently, a group of complement proteins has been suggested to be highly relevant in various complement-associated disorders, namely the human factor H (FH) protein family. This family of closely related proteins consists of FH, FH-like protein 1, and five factor H-related proteins, and they have been linked to eye, kidney, infectious, vascular, and autoimmune diseases as well as cancer. The goal of this review is to provide a comprehensive overview of the available data on circulating levels of FH and its related proteins in different pathologies. In addition, we examined the current literature to determine the clinical utility of measuring levels of the FH protein family in health and disease. Finally, we discuss future steps that are needed to make their clinical translation a reality.
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Gouda HR, Talaat IM, Bouzid A, El-Assi H, Nabil A, Venkatachalam T, Manasa Bhamidimarri P, Wohlers I, Mahdami A, EL-Gendi S, ElKoraie A, Busch H, Saber-Ayad M, Hamoudi R, Baddour N. Genetic analysis of CFH and MCP in Egyptian patients with immune-complex proliferative glomerulonephritis. Front Immunol 2022; 13:960068. [PMID: 36211394 PMCID: PMC9539770 DOI: 10.3389/fimmu.2022.960068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/30/2022] [Indexed: 11/19/2022] Open
Abstract
Glomerulonephritis (GN) is a complex disease with intricate underlying pathogenic mechanisms. The possible role of underlying complement dysregulation is not fully elucidated in some GN subsets, especially in the setting of autoimmunity or infection. In the current study, diagnosed cases of lupus nephritis (LN) and post-infectious GN (PIGN) were recruited for molecular genetic analysis and targeted next-generation DNA sequencing was performed for two main complement regulating genes: in the fluid phase; CFH, and on tissue surfaces; MCP. Three heterozygous pathogenic variants in CFH (Q172*, W701*, and W1096*) and one likely pathogenic heterozygous variant in MCP (C223R) have been identified in four of the studied LN cases. Additionally, among the several detected variants of uncertain significance, one novel variant (CFH:F614S) was identified in 74% of the studied LN cases and in 65% of the studied PIGN cases. This variant was detected for the first time in the Egyptian population. These findings suggest that subtle mutations may be present in complement regulating genes in patients with immune-complex mediated category of GN that may add to the disease pathogenesis. These findings also call for further studies to delineate the impact of these gene variants on the protein function, the disease course, and outcome.
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Affiliation(s)
- Heba R. Gouda
- Pathology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Iman M. Talaat
- Pathology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
- Clinical Sciences Department, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- *Correspondence: Iman M. Talaat, ; Rifat Hamoudi,
| | - Amal Bouzid
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Hoda El-Assi
- Human Genetics Unit, Pathology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Amira Nabil
- Human Genetics Department, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Thenmozhi Venkatachalam
- Department of Physiology and Immunology, College of Medicine, Khalifa University, Abu Dhabi, United Arab Emirates
| | | | - Inken Wohlers
- Medical Systems Biology Division, Lübeck Institute of Experimental Dermatology and Institute for Cardiogenetics, University of Lübeck, Lübeck, Germany
| | - Amena Mahdami
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Saba EL-Gendi
- Pathology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Ahmed ElKoraie
- Nephrology Unit, Internal Medicine Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Hauke Busch
- Medical Systems Biology Division, Lübeck Institute of Experimental Dermatology and Institute for Cardiogenetics, University of Lübeck, Lübeck, Germany
| | - Maha Saber-Ayad
- Clinical Sciences Department, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- Pharmacology Department, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Rifat Hamoudi
- Clinical Sciences Department, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- Division of Surgery and Interventional Science, University College London, London, United Kingdom
- *Correspondence: Iman M. Talaat, ; Rifat Hamoudi,
| | - Nahed Baddour
- Pathology Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt
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4
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Fakhouri F, Schwotzer N, Golshayan D, Frémeaux-Bacchi V. The rational use of complement inhibitors in kidney diseases. Kidney Int Rep 2022; 7:1165-1178. [PMID: 35685323 PMCID: PMC9171628 DOI: 10.1016/j.ekir.2022.02.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/15/2022] [Accepted: 02/21/2022] [Indexed: 12/14/2022] Open
Abstract
The development of complement inhibitors represented one of the major breakthroughs in clinical nephrology in the last decade. Complement inhibition has dramatically transformed the outcome of one of the most severe kidney diseases, the atypical hemolytic uremic syndrome (aHUS), a prototypic complement-mediated disorder. The availability of complement inhibitors has also opened new promising perspectives for the management of several other kidney diseases in which complement activation is involved to a variable extent. With the rapidly growing number of complement inhibitors tested in a rapidly increasing number of indications, a rational use of this innovative and expensive new therapeutic class has become crucial. The present review aims to summarize what we know, and what we still ignore, regarding complement activation and therapeutic inhibition in kidney diseases. It also provides some clues and elements of thoughts for a rational approach of complement modulation in kidney diseases.
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Affiliation(s)
- Fadi Fakhouri
- Service de Néphrologie et d'hypertension, Département de Médecine, Centre Hospitalier Universitaire Vaudois (CHUV), Université de Lausanne, Lausanne, Switzerland
- Correspondence: Fadi Fakhouri, Service de Néphrologie et d'hypertension, Département de Médecine, Centre Hospitalier Universitaire Vaudois (CHUV), Université de Lausanne, Lausanne, Switzerland.
| | - Nora Schwotzer
- Service de Néphrologie et d'hypertension, Département de Médecine, Centre Hospitalier Universitaire Vaudois (CHUV), Université de Lausanne, Lausanne, Switzerland
| | - Déla Golshayan
- Centre de Transplantation d'organes, Département de Médecine, Centre Hospitalier Universitaire Vaudois (CHUV), Université de Lausanne, Lausanne, Switzerland
| | - Véronique Frémeaux-Bacchi
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service d'Immunologie, Paris University, Paris, France
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5
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Ham YJ, Nicklason E, Wightman T, Akom S, Sandhu K, Harraka P, Colville D, Catran A, Barit D, Langsford D, Pianta T, Foote A, Buchanan R, Mack H, Savige J. Retinal drusen are more common and larger in SLE with renal impairment. Kidney Int Rep 2022; 7:848-856. [PMID: 35497809 PMCID: PMC9039474 DOI: 10.1016/j.ekir.2022.01.1063] [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: 08/09/2021] [Revised: 01/18/2022] [Accepted: 01/24/2022] [Indexed: 11/14/2022] Open
Abstract
Introduction Complement has been implicated in systemic lupus erythematosus (SLE) pathogenesis on the basis of the associations with inherited complement defects and genome-wide association study risk alleles, glomerular deposits, reduced serum levels, and occasional reports of retinal drusen. This study examined drusen in SLE and their clinical significance. Methods This cross-sectional observational study compared individuals with SLE recruited from renal and rheumatology clinics with hospital controls. Participants were reviewed for clinical features and underwent imaging with a nonmydriatic retinal camera. Deidentified images were examined by 2 trained graders for drusen number and size using a grid overlay. Results The cohort with SLE (n = 65) comprised 55 women (85%) and 10 men (15%) with a median age of 47 years (interquartile range 35–59), where 23 (35%) were of southern European or Asian ancestry, and 32 (49%) had biopsy-proven lupus nephritis. Individuals with SLE had higher mean drusen numbers than controls (27 ± 60, 3 ± 9, respectively, P = 0.001), more drusen counts ≥10 (31, 48% and 3, 5%, respectively, P < 0.001), and more medium-large drusen (14, 22% and 3, 5%, respectively, P < 0.001). In SLE, mean drusen counts were higher, and drusen were larger, with an estimated glomerular filtration rate (eGFR) <90 ml/min per 1.73 m2 (P = 0.02, P = 0.02, respectively) or class IV nephritis (P = 0.03, P = 0.02). Conclusion Drusen composition resembles that of glomerular immune deposits. CFH controls complement activation in the extracellular matrix and CFH risk variants are shared by drusen in macular degeneration and by SLE. CFH represents a possible treatment target for SLE especially with renal impairment.
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6
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The Syndromes of Thrombotic Microangiopathy: A Critical Appraisal on Complement Dysregulation. J Clin Med 2021; 10:jcm10143034. [PMID: 34300201 PMCID: PMC8307963 DOI: 10.3390/jcm10143034] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 01/12/2023] Open
Abstract
Thrombotic microangiopathy (TMA) is a rare and potentially life-threatening condition that can be caused by a heterogeneous group of diseases, often affecting the brain and kidneys. TMAs should be classified according to etiology to indicate targets for treatment. Complement dysregulation is an important cause of TMA that defines cases not related to coexisting conditions, that is, primary atypical hemolytic uremic syndrome (HUS). Ever since the approval of therapeutic complement inhibition, the approach of TMA has focused on the recognition of primary atypical HUS. Recent advances, however, demonstrated the pivotal role of complement dysregulation in specific subtypes of patients considered to have secondary atypical HUS. This is particularly the case in patients presenting with coexisting hypertensive emergency, pregnancy, and kidney transplantation, shifting the paradigm of disease. In contrast, complement dysregulation is uncommon in patients with other coexisting conditions, such as bacterial infection, drug use, cancer, and autoimmunity, among other disorders. In this review, we performed a critical appraisal on complement dysregulation and the use of therapeutic complement inhibition in TMAs associated with coexisting conditions and outline a pragmatic approach to diagnosis and treatment. For future studies, we advocate the term complement-mediated TMA as opposed to the traditional atypical HUS-type classification.
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Zickuhr L, Herlitz LC, Chatterjee S. A 22-Year-Old Woman With Systemic Lupus Erythematosus Presents With Two Damaged Kidneys, One Seizure, No Platelets, and Many Possible Diagnoses. Arthritis Care Res (Hoboken) 2018; 70:1686-1693. [PMID: 29579358 DOI: 10.1002/acr.23561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 03/20/2018] [Indexed: 11/09/2022]
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8
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Marin AV, Cárdenas PP, Jiménez-Reinoso A, Muñoz-Ruiz M, Regueiro JR. Lymphocyte integration of complement cues. Semin Cell Dev Biol 2018; 85:132-142. [PMID: 29438807 DOI: 10.1016/j.semcdb.2018.02.005] [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: 12/14/2017] [Accepted: 02/08/2018] [Indexed: 12/17/2022]
Abstract
We address current data, views and puzzles on the emerging topic of regulation of lymphocytes by complement proteins or fragments. Such regulation is believed to take place through complement receptors (CR) and membrane complement regulators (CReg) involved in cell function or protection, respectively, including intracellular signalling. Original observations in B cells clearly support that complement cues through CR improve their performance. Other lymphocytes likely integrate complement-derived signals, as most lymphoid cells constitutively express or regulate CR and CReg upon activation. CR-induced signals, particularly by anaphylatoxins, clearly regulate lymphoid cell function. In contrast, data obtained by CReg crosslinking using antibodies are not always confirmed in human congenital deficiencies or knock-out mice, casting doubts on their physiological relevance. Unsurprisingly, human and mouse complement systems are not completely homologous, adding further complexity to our still fragmentary understanding of complement-lymphocyte interactions.
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Affiliation(s)
- Ana V Marin
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Paula P Cárdenas
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Anaïs Jiménez-Reinoso
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Miguel Muñoz-Ruiz
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Jose R Regueiro
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine and 12 de Octubre Health Research Institute (imas12), Madrid, Spain.
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9
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Membrane attack complex (mac) deposition in lupus nephritis is associated with hypertension and poor clinical response to treatment. Semin Arthritis Rheum 2018; 48:256-262. [PMID: 29395256 DOI: 10.1016/j.semarthrit.2018.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/30/2017] [Accepted: 01/04/2018] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To study membrane attack complex in lupus nephritis as a potential biomarker for disease intensity and prognostic indicator for response to treatment. METHODS Immunohistochemistry was performed using unconjugated, murine anti-human complement C9 on kidney biopsies from 30 SLE patients who fulfilled 4 ACR or SLICC criteria. Clinical parameters were assessed at time of biopsy, 6 and 12 months. RESULTS 30 renal biopsies were obtained from patients with Class II (2), III (5), IV (8), V (5), III+V (8) and IV+V (2). 13/30 (43.3%) biopsies stained positive for glomerular C9. Patients with positive C9 had significantly higher blood pressure, trend towards lower C3, and male gender. There was no significant difference for ISN/RPN class, activity or chronicity indices between C9 positive and negative groups. 5/11 (45.5%) patients positive for C9 did not respond to therapy at 6 months compared with 2/15 (13.3%) patients negative for C9. C9 positive patients were more likely to be a non-responder at 6 months (OR = 5.4, 95% CI: 0.8, 36.4) compared to C9 negative patients. After adjusting for systolic blood pressure, compliance to treatment and proteinuria in a multivariate logistic model, C9 positive patients remained more likely to be non-responders (OR = 4.6, 95% CI: 0.3, 70.9). CONCLUSION This study suggests that MAC deposition measured as C9 staining may be a biomarker for more intense disease and poor response to treatment in lupus nephritis. MAC staining may be useful in routine studies of lupus biopsies and identify patients at risk for aggressive disease who may be candidates for novel therapies targeting terminal complement pathway.
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10
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Thurman JM, Frazer-Abel A, Holers VM. The Evolving Landscape for Complement Therapeutics in Rheumatic and Autoimmune Diseases. Arthritis Rheumatol 2017; 69:2102-2113. [PMID: 28732131 PMCID: PMC5659941 DOI: 10.1002/art.40219] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 07/18/2017] [Indexed: 12/13/2022]
Abstract
The complement system is increasingly understood to play major roles in the pathogenesis of human inflammatory and autoimmune diseases. Because of this situation, there are rapidly expanding commercial efforts to develop novel complement inhibitors and effector pathway-modulating drugs. This review provides insights into the evolving understanding of the complement system components, mechanisms of activation within and across the 3 pathways (classical, alternative, and lectin), how the pathways are normally controlled and then dysregulated in target tissues, and what diseases are known to be, in large part, complement-dependent through the successful development and approval of complement therapeutics in patients. Mechanisms of complement activation in rheumatoid arthritis, lupus, and thrombotic microangiopathies are also illustrated. In addition, the specific therapeutic drugs that are both approved and under development are discussed in the context of both nonrheumatic and rheumatic diseases. Finally, the methods by which the complement system can be assessed in humans through biomarker studies are outlined, with the goal of understanding, in specific patients, how the system is functioning.
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Affiliation(s)
- Joshua M. Thurman
- University of Colorado Denver, Division of Nephrology and Hypertension, Aurora, CO, USA
| | - Ashley Frazer-Abel
- University of Colorado Denver, Division of Rheumatology, Aurora, CO, USA
- Exsera BioLabs, University of Colorado Denver, Aurora, CO, USA
| | - V. Michael Holers
- University of Colorado Denver, Division of Rheumatology, Aurora, CO, USA
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11
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de Holanda MI, Pôrto LC, Wagner T, Christiani LF, Palma LMP. Use of eculizumab in a systemic lupus erythemathosus patient presenting thrombotic microangiopathy and heterozygous deletion in CFHR1-CFHR3. A case report and systematic review. Clin Rheumatol 2017; 36:2859-2867. [PMID: 28905254 DOI: 10.1007/s10067-017-3823-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/30/2017] [Accepted: 09/04/2017] [Indexed: 02/01/2023]
Abstract
The association of thrombotic microangiopathy (TMA) with systemic lupus erythematosus (SLE) has been described in 0.5 to 10% of cases, and patients present worse outcome. TMA is described as the association of microangiopathic hemolytic anemia, thrombocytopenia, and an organ injury, frequently the kidney. This study describes a successful case of use of eculizumab in a patient with SLE and TMA refractory to standard therapy, and provides a literature review. Case description and search in PubMed and MEDLINE using systemic lupus erythemathous and/or antiphospholipid syndrome (APS) and eculizumab retrieved 15 case reports. Eighteen-year-old female presented acute renal failure and TMA and was diagnosed with SLE. Steroids and IV cyclophosphamide were started together with plasma exchange. After 55 days, she still persisted with microangiopathic anemia, thrombocytopenia, and anuria, and eculizumab was introduced. She had rapid improvement in hematological parameters, and dialysis was discontinued 25 days after the first dose. Genetic analysis showed large heterozygous deletion encompassing the entire CFHR1 and CFHR3, a finding previously associated with patients presenting atypical hemolytic-uremic syndrome (aHUS). Twenty patients who received eculizumab with SLE and/or APS have been published to date: 11 were female and mean age at presentation was 31 years. Seven out of the 20 patients presented only SLE, 5 patients only APS and 8 patients both SLE and APS. Eighteen patients underwent plasma exchange, with a mean of 20 (4-120) sessions per patient. Thirteen patients received rituximab. Hematological response was evident in 100% and kidney recovery in 85% of patients. The terminal complement blockade with eculizumab is an optional treatment for patients with SLE and/or APS presenting TMA and refractory to current immunosuppression therapies. Genetic testing may help recognize patients with aHUS and SLE/APS and therefore help to determine length of treatment with eculizumab.
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Affiliation(s)
- Maria Izabel de Holanda
- Department of Nephrology and Kidney Transplant, Hospital Federal de Bonsucesso, Av. Londres 616, Prédio 1, segundo andar, Departamento de Nefrologia e Transplante Renal, Rio de Janeiro, Brazil.
| | - Luis Cristóvão Pôrto
- Histocompatibility and Cryopreservation Laboratory, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Teresa Wagner
- Department of Nephrology and Kidney Transplant, Hospital Federal de Bonsucesso, Av. Londres 616, Prédio 1, segundo andar, Departamento de Nefrologia e Transplante Renal, Rio de Janeiro, Brazil
| | - Luis Fernando Christiani
- Department of Nephrology and Kidney Transplant, Hospital Federal de Bonsucesso, Av. Londres 616, Prédio 1, segundo andar, Departamento de Nefrologia e Transplante Renal, Rio de Janeiro, Brazil
| | - Lilian M P Palma
- Department of Pediatric Nephrology, Unicamp, State University of Campinas, Campinas, Brazil
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12
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Ellinghaus U, Cortini A, Pinder CL, Le Friec G, Kemper C, Vyse TJ. Dysregulated CD46 shedding interferes with Th1-contraction in systemic lupus erythematosus. Eur J Immunol 2017; 47:1200-1210. [PMID: 28444759 PMCID: PMC5507296 DOI: 10.1002/eji.201646822] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/01/2017] [Accepted: 04/20/2017] [Indexed: 12/23/2022]
Abstract
IFN‐γ‐producing T helper 1 (Th1) cell responses mediate protection against infections but uncontrolled Th1 activity also contributes to a broad range of autoimmune diseases. Autocrine complement activation has recently emerged as key in the induction and contraction of human Th1 immunity: activation of the complement regulator CD46 and the C3aR expressed by CD4+ T cells via autocrine generated ligands C3b and C3a, respectively, are critical to IFN‐γ production. Further, CD46‐mediated signals also induce co‐expression of immunosuppressive IL‐10 in Th1 cells and transition into a (self)‐regulating and contracting phase. In consequence, C3 or CD46‐deficient patients suffer from recurrent infections while dysregulation of CD46 signaling contributes to Th1 hyperactivity in rheumatoid arthritis and multiple sclerosis. Here, we report a defect in CD46‐regulated Th1 contraction in patients with systemic lupus erythematosus (SLE). We observed that MMP‐9‐mediated increased shedding of soluble CD46 by Th1 cells was associated with this defect and that inhibition of MMP‐9 activity normalized release of soluble CD46 and restored Th1 contraction in patients’ T cells. These data may deliver the first mechanistic explanation for the increased serum CD46 levels observed in SLE patients and indicate that targeting CD46‐cleaving proteases could be a novel avenue to modulate Th1 responses.
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Affiliation(s)
- Ursula Ellinghaus
- Division of Genetics and Molecular Medicine, Department of Medical and Molecular Genetics, King's College London, Guy's Hospital, London, UK
| | - Andrea Cortini
- Division of Genetics and Molecular Medicine, Department of Medical and Molecular Genetics, King's College London, Guy's Hospital, London, UK
| | - Christopher L Pinder
- Division of Genetics and Molecular Medicine, Department of Medical and Molecular Genetics, King's College London, Guy's Hospital, London, UK
| | - Gaelle Le Friec
- MRC Centre for Transplantation, Division of Transplant Immunology and Mucosal Biology, King's College London, UK
| | - Claudia Kemper
- MRC Centre for Transplantation, Division of Transplant Immunology and Mucosal Biology, King's College London, UK.,Laboratory of Molecular Immunology and the Immunology Center, National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Timothy J Vyse
- Division of Genetics and Molecular Medicine, Department of Medical and Molecular Genetics, King's College London, Guy's Hospital, London, UK
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13
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Arkema EV, Svenungsson E, Von Euler M, Sjöwall C, Simard JF. Stroke in systemic lupus erythematosus: a Swedish population-based cohort study. Ann Rheum Dis 2017; 76:1544-1549. [DOI: 10.1136/annrheumdis-2016-210973] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/27/2017] [Accepted: 03/24/2017] [Indexed: 12/24/2022]
Abstract
ObjectiveTo study the occurrence of ischaemic and haemorrhagic stroke in systemic lupus erythematosus (SLE) compared with the general population by age, sex and time since SLE diagnosisMethodsAdults with incident SLE were identified from the Swedish National Patient Register (NPR, n=3390) and general population comparators from the Total Population Register were matched on age, sex and county (n=16730). Individuals were followed prospectively until first of death, December 2013, emigration or incident stroke (identified from the NPR, Cause of Death Register and the Stroke Register). Incidence rates, rate differences and HR were estimated comparing SLE with non-SLE. Estimates were stratified by sex, age and time since diagnosis.ResultsWe observed 126 strokes in SLE and 304 in the general population. Individuals with SLE had a twofold increased rate of ischaemic stroke compared with the general population (HR 2.2; 95% CI 1.7 to 2.8). The HR for intracerebral haemorrhage was 1.4 (95% CI 0.7 to 2.8). There was effect modification by sex and age, with the highest HRs for females and individuals <50 years old. The HR for ischaemic stroke was highest in the first year of follow-up (3.7; 95% CI 2.1 to 6.5).ConclusionsThe relative risk of ischaemic stroke in SLE was more than doubled compared with the general population, and importantly, the highest relative risks were observed within the first year after SLE diagnosis. Thus, the first encounter with patients presents an opportunity for rheumatologists to screen for risk factors and intervene.
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14
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Expanding the therapeutic options for renal involvement in lupus: eculizumab, available evidence. Rheumatol Int 2017; 37:1249-1255. [DOI: 10.1007/s00296-017-3686-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/22/2017] [Indexed: 12/25/2022]
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Yu Y, Wagner EK, Souied EH, Seitsonen S, Immonen IJ, Häppölä P, Raychaudhuri S, Daly MJ, Seddon JM. Protective coding variants in CFH and PELI3 and a variant near CTRB1 are associated with age-related macular degeneration†. Hum Mol Genet 2016; 25:5276-5285. [PMID: 28011711 PMCID: PMC6078639 DOI: 10.1093/hmg/ddw336] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 09/16/2016] [Accepted: 09/29/2016] [Indexed: 12/17/2022] Open
Abstract
Although numerous common age-related macular degeneration (AMD) alleles have been discovered using genome-wide association studies, substantial disease heritability remains unexplained. We sought to identify additional common and rare variants associated with advanced AMD. A total of 4,332 cases and 25,268 controls of European ancestry from three different populations were genotyped using the Illumina Infinium HumanExome BeadChip. We performed meta-analyses to identify associations with common variants, and single variant and gene-based burden tests to identify rare variants. Two protective, low-frequency, non-synonymous variants were significantly associated with a decrease in AMD risk: A307V in PELI3 (odds ratio [OR] = 0.14, P = 4.3 × 10-10) and N1050Y in CFH (OR = 0.76, P = 6.2 × 10-12). The new variants have a large effect size, similar to some rare mutations we reported previously in a targeted sequencing study, which remain significant in this analysis: CFH R1210C (OR = 18.82, P = 3.5 × 10-07), C3 K155Q (OR = 3.27, P = 1.5 × 10-10) and C9 P167S (OR = 2.04, P = 2.8 × 10-07). We also identified a strong protective signal for a common variant (rs8056814) near CTRB1 associated with a decrease in AMD risk (logistic regression: OR = 0.71, P = 1.8 × 10-07). Suggestive protective loci were identified in the COL4A3 and APOH genes. Our results support the involvement of common and low-frequency protective variants in this vision-threatening condition. This study expands the roles of the innate immune pathway as well as the extracellular matrix and high-density lipoprotein pathways in the aetiology of AMD.
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Affiliation(s)
- Yi Yu
- Ophthalmic Epidemiology and Genetics Service, New England Eye Center, Tufts Medical Center, Boston, MA, USA
| | - Erin K. Wagner
- Ophthalmic Epidemiology and Genetics Service, New England Eye Center, Tufts Medical Center, Boston, MA, USA
- Department of Ophthalmology, Tufts University School of Medicine, Boston, MA, USA
| | - Eric H. Souied
- Hôpital Intercommunal, Hôpital Henri Mondor, Créteil Université Paris Est, Paris, France
| | | | | | - Paavo Häppölä
- Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Soumya Raychaudhuri
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
- Partners HealthCare Center for Personalized Genetic Medicine, Boston, MA, USA
- Division of Genetics, Brigham and Women's Hospital, Boston, MA, USA
- Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital, Boston, MA, USA
- Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK
| | - Mark J. Daly
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
- Partners HealthCare Center for Personalized Genetic Medicine, Boston, MA, USA
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA and
| | - Johanna M. Seddon
- Ophthalmic Epidemiology and Genetics Service, New England Eye Center, Tufts Medical Center, Boston, MA, USA
- Department of Ophthalmology, Tufts University School of Medicine, Boston, MA, USA
- Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, USA
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Atypical hemolytic uremic syndrome in the setting of complement-amplifying conditions: case reports and a review of the evidence for treatment with eculizumab. J Nephrol 2016; 30:347-362. [PMID: 27848226 PMCID: PMC5437142 DOI: 10.1007/s40620-016-0357-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 10/14/2016] [Indexed: 01/20/2023]
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare, genetic, progressive, life-threatening form of thrombotic microangiopathy (TMA) predominantly caused by dysregulation of the alternative pathway of the complement system. Complement-amplifying conditions (CACs), including pregnancy complications [preeclampsia, HELLP (hemolysis, elevated liver enzymes, low platelet count) syndrome], malignant hypertension, autoimmune diseases, transplantation, and others, are associated with the onset of TMA in up to 69 % of cases of aHUS. CACs activate the alternative pathway of complement and may be comorbid with aHUS or may unmask a previously undiagnosed case. In this review, three case reports are presented illustrating the onset and diagnosis of aHUS in the setting of different CACs (pregnancy complications, malignant hypertension, renal transplantation). The report also reviews the evidence for a variety of CACs, including those mentioned above as well as infections and drug-induced TMA, and the overlap with aHUS. Finally, we introduce an algorithm for diagnosis and treatment of aHUS in the setting of CACs. If TMA persists despite initial management for the specific CAC, aHUS should be considered. The terminal complement inhibitor eculizumab should be initiated for all patients with confirmed diagnosis of aHUS, with or without a comorbid CAC.
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Zhang C, Zhang DF, Wu ZG, Peng DH, Chen J, Ni J, Tang W, Xu L, Yao YG, Fang YR. Complement factor H and susceptibility to major depressive disorder in Han Chinese. Br J Psychiatry 2016; 208:446-52. [PMID: 26941266 DOI: 10.1192/bjp.bp.115.163790] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 08/21/2015] [Indexed: 01/25/2023]
Abstract
BACKGROUND Accumulating evidence suggests that altered immunity contributes to the development of major depressive disorder (MDD). AIMS To examine whether complement factor H (CFH), a regulator of activation of the alternative pathway of the complement cascade, confers susceptibility to MDD. METHOD Expression analyses were tested in 53 unmedicated people with MDD and 55 healthy controls. A two-stage genetic association analysis was performed in 3323 Han Chinese with or without MDD. Potential associations between CFH single nucleotide polymorphisms and age at MDD onset were evaluated. RESULTS CFH levels were significantly lower in the MDD group at both protein and mRNA levels (P = 0.009 and P = 0.014 respectively). A regulatory variant in the CFH gene, rs1061170, showed statistically significant genotypic and allelic differences between the MDD and control groups (genotypic P = 0.0005, allelic P = 0.0001). Kaplan-Meier survival analysis showed that age at onset of MDD was significantly associated with the C allele of rs1061170 (log rank statistic χ(2) = 6.82, P = 0.009). The C-allele carriers had a younger age at onset of MDD (22.2 years, s.d. = 4.0) than those without the C allele (23.6 years, s.d. = 4.3). CONCLUSIONS CFH is likely to play an important role in the development of MDD. rs1061170 has an important effect on age at onset of MDD in Han Chinese and may therefore be related to early pathogenesis of MDD, although further study is needed.
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Affiliation(s)
- Chen Zhang
- Chen Zhang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai and Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Deng-Feng Zhang, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Zhi-Guo Wu, MD, PhD, Dai-Hui Peng, MD, PhD, Jun Chen, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai; Jianliang Ni, MD, Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang; Wenxin Tang, MD, Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang; Lin Xu, PhD, Yong-Gang Yao, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan and CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Shanghai; Yi-Ru Fang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Deng-Feng Zhang
- Chen Zhang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai and Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Deng-Feng Zhang, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Zhi-Guo Wu, MD, PhD, Dai-Hui Peng, MD, PhD, Jun Chen, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai; Jianliang Ni, MD, Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang; Wenxin Tang, MD, Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang; Lin Xu, PhD, Yong-Gang Yao, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan and CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Shanghai; Yi-Ru Fang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhi-Guo Wu
- Chen Zhang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai and Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Deng-Feng Zhang, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Zhi-Guo Wu, MD, PhD, Dai-Hui Peng, MD, PhD, Jun Chen, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai; Jianliang Ni, MD, Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang; Wenxin Tang, MD, Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang; Lin Xu, PhD, Yong-Gang Yao, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan and CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Shanghai; Yi-Ru Fang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Dai-Hui Peng
- Chen Zhang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai and Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Deng-Feng Zhang, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Zhi-Guo Wu, MD, PhD, Dai-Hui Peng, MD, PhD, Jun Chen, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai; Jianliang Ni, MD, Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang; Wenxin Tang, MD, Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang; Lin Xu, PhD, Yong-Gang Yao, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan and CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Shanghai; Yi-Ru Fang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jun Chen
- Chen Zhang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai and Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Deng-Feng Zhang, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Zhi-Guo Wu, MD, PhD, Dai-Hui Peng, MD, PhD, Jun Chen, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai; Jianliang Ni, MD, Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang; Wenxin Tang, MD, Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang; Lin Xu, PhD, Yong-Gang Yao, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan and CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Shanghai; Yi-Ru Fang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jianliang Ni
- Chen Zhang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai and Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Deng-Feng Zhang, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Zhi-Guo Wu, MD, PhD, Dai-Hui Peng, MD, PhD, Jun Chen, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai; Jianliang Ni, MD, Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang; Wenxin Tang, MD, Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang; Lin Xu, PhD, Yong-Gang Yao, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan and CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Shanghai; Yi-Ru Fang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenxin Tang
- Chen Zhang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai and Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Deng-Feng Zhang, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Zhi-Guo Wu, MD, PhD, Dai-Hui Peng, MD, PhD, Jun Chen, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai; Jianliang Ni, MD, Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang; Wenxin Tang, MD, Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang; Lin Xu, PhD, Yong-Gang Yao, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan and CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Shanghai; Yi-Ru Fang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lin Xu
- Chen Zhang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai and Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Deng-Feng Zhang, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Zhi-Guo Wu, MD, PhD, Dai-Hui Peng, MD, PhD, Jun Chen, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai; Jianliang Ni, MD, Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang; Wenxin Tang, MD, Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang; Lin Xu, PhD, Yong-Gang Yao, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan and CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Shanghai; Yi-Ru Fang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yong-Gang Yao
- Chen Zhang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai and Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Deng-Feng Zhang, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Zhi-Guo Wu, MD, PhD, Dai-Hui Peng, MD, PhD, Jun Chen, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai; Jianliang Ni, MD, Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang; Wenxin Tang, MD, Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang; Lin Xu, PhD, Yong-Gang Yao, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan and CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Shanghai; Yi-Ru Fang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yi-Ru Fang
- Chen Zhang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai and Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Deng-Feng Zhang, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan; Zhi-Guo Wu, MD, PhD, Dai-Hui Peng, MD, PhD, Jun Chen, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai; Jianliang Ni, MD, Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou, Zhejiang; Wenxin Tang, MD, Hangzhou Seventh People's Hospital, Hangzhou, Zhejiang; Lin Xu, PhD, Yong-Gang Yao, PhD, Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan and CAS Center for Excellence in Brain Science, Chinese Academy of Sciences, Shanghai; Yi-Ru Fang, MD, PhD, Division of Mood Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Zhai YL, Meng SJ, Zhu L, Shi SF, Wang SX, Liu LJ, Lv JC, Yu F, Zhao MH, Zhang H. Rare Variants in the Complement Factor H-Related Protein 5 Gene Contribute to Genetic Susceptibility to IgA Nephropathy. J Am Soc Nephrol 2016; 27:2894-905. [PMID: 26825529 DOI: 10.1681/asn.2015010012] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 12/20/2015] [Indexed: 11/03/2022] Open
Abstract
A recent genome-wide association study of IgA nephropathy (IgAN) identified 1q32, which contains multiple complement regulatory genes, including the complement factor H (CFH) gene and the complement factor H-related (CFHRs) genes, as an IgAN susceptibility locus. Abnormal complement activation caused by a mutation in CFHR5 was shown to cause CFHR5 nephropathy, which shares many characteristics with IgAN. To explore the genetic effect of variants in CFHR5 on IgAN susceptibility, we recruited 500 patients with IgAN and 576 healthy controls for genetic analysis. We sequenced all exons and their intronic flanking regions as well as the untranslated regions of CFHR5 and compared the frequencies of identified variants using the sequence kernel association test. We identified 32 variants in CFHR5, including 28 rare and four common variants. The distribution of rare variants in CFHR5 in patients with IgAN differed significantly from that in controls (P=0.002). Among the rare variants, in silico programs predicted nine as potential functional variants, which we then assessed in functional assays. Compared with wild-type CFHR5, three recombinant CFHR5 proteins, CFHR5-M (c.508G>A/p.Val170Met), CFHR5-S (c.533A>G/p.Asn178Ser), and CFHR5-D (c.822A>T/p.Glu274Asp), showed significantly higher C3b binding capacity (CFHR5-M: 109.67%±3.54%; P=0.02; CFHR5-S: 174.27%±9.78%; P<0.001; CFHR5-D: 127.25%±1.75%; P<0.001), whereas another recombinant CFHR5 (c.776T>A/p.Leu259Termination) showed less C3b binding (56.89%±0.57%; P<0.001). Our study found that rare variants in CFHR5 may contribute to the genetic susceptibility to IgAN, which suggests that CFHR5 is an IgAN susceptibility gene.
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Affiliation(s)
- Ya-Ling Zhai
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China; Institute of Nephrology, Peking University, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Si-Jun Meng
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China; Institute of Nephrology, Peking University, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Li Zhu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China; Institute of Nephrology, Peking University, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Su-Fang Shi
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China; Institute of Nephrology, Peking University, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Su-Xia Wang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China; Institute of Nephrology, Peking University, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Li-Jun Liu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China; Institute of Nephrology, Peking University, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Ji-Cheng Lv
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China; Institute of Nephrology, Peking University, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Feng Yu
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China; Institute of Nephrology, Peking University, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Ming-Hui Zhao
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China; Institute of Nephrology, Peking University, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
| | - Hong Zhang
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, China; Institute of Nephrology, Peking University, Beijing, China; Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China; and Key Laboratory of Chronic Kidney Disease Prevention and Treatment (Peking University), Ministry of Education, Beijing, China
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Martin M, Leffler J, Smoląg KI, Mytych J, Björk A, Chaves LD, Alexander JJ, Quigg RJ, Blom AM. Factor H uptake regulates intracellular C3 activation during apoptosis and decreases the inflammatory potential of nucleosomes. Cell Death Differ 2016; 23:903-11. [PMID: 26768663 DOI: 10.1038/cdd.2015.164] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 11/20/2015] [Accepted: 11/24/2015] [Indexed: 01/06/2023] Open
Abstract
Factor H (FH) binds apoptotic cells to limit the inflammatory potential of complement. Here we report that FH is actively internalized by apoptotic cells to enhance cathepsin L-mediated cleavage of endogenously expressed C3, which results in increased surface opsonization with iC3b. In addition, internalized FH forms complexes with nucleosomes, facilitates their phagocytosis by monocytes and induces an anti-inflammatory biased cytokine profile. A similar cytokine response was noted for apoptotic cells coated with FH, confirming that FH diminishes the immunogenic and inflammatory potential of autoantigens. These findings were supported by in vivo observations from CFH(-/-) MRL-lpr mice, which exhibited higher levels of circulating nucleosomes and necrotic cells than their CFH(+/+) littermates. This unconventional function of FH broadens the established view of apoptotic cell clearance and appears particularly important considering the strong associations with genetic FH alterations and diseases such as systemic lupus erythematosus and age-related macular degeneration.
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Affiliation(s)
- M Martin
- Department of Translational Medicine Malmö, Section of Medical Protein Chemistry, Lund University, Lund, Sweden
| | - J Leffler
- Department of Translational Medicine Malmö, Section of Medical Protein Chemistry, Lund University, Lund, Sweden
| | - K I Smoląg
- Department of Translational Medicine Malmö, Section of Medical Protein Chemistry, Lund University, Lund, Sweden
| | - J Mytych
- Department of Translational Medicine Malmö, Section of Medical Protein Chemistry, Lund University, Lund, Sweden
| | - A Björk
- Department of Translational Medicine Malmö, Section of Medical Protein Chemistry, Lund University, Lund, Sweden
| | - L D Chaves
- Department of Medicine, Section of Nephrology, University at Buffalo, Buffalo, NY, USA
| | - J J Alexander
- Department of Medicine, Section of Nephrology, University at Buffalo, Buffalo, NY, USA
| | - R J Quigg
- Department of Medicine, Section of Nephrology, University at Buffalo, Buffalo, NY, USA
| | - A M Blom
- Department of Translational Medicine Malmö, Section of Medical Protein Chemistry, Lund University, Lund, Sweden
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Bao L, Cunningham PN, Quigg RJ. Complement in Lupus Nephritis: New Perspectives. KIDNEY DISEASES 2015; 1:91-9. [PMID: 27536669 DOI: 10.1159/000431278] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 05/06/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND Systemic lupus erythematosus (SLE) is an autoimmune disorder caused by loss of tolerance to self-antigens, the production of autoantibodies and deposition of complement-fixing immune complexes (ICs) in injured tissues. SLE is characterized by a wide range of clinical manifestations and targeted organs, with lupus nephritis being one of the most serious complications. The complement system consists of three pathways and is tightly controlled by a set of regulatory proteins to prevent injudicious complement activation on host tissue. The involvement of the complement system in the pathogenesis of SLE is well accepted; yet, its exact role is still not clear. SUMMARY Complement plays dual roles in the pathogenesis of SLE. On the one hand, the complement system appears to have protective features in that hereditary homozygous deficiencies of classical pathway components, such as C1q and C4, are associated with an increased risk for SLE. On the other hand, IC-mediated activation of complement in affected tissues is clearly evident in both experimental and human SLE along with pathological features that are logical consequences of complement activation. Studies in genetically altered mice have shown that lack of complement inhibitors, such as complement factor H (CFH) or decay-accelerating factor (DAF) accelerates the development of experimental lupus nephritis, while treatment with recombinant protein inhibitors, such as Crry-Ig, CR2-Crry, CR2-DAF and CR2-CFH, ameliorates the disease development. Complement-targeted drugs, including soluble complement receptor 1 (TP10), C1 esterase inhibitor and a monoclonal anti-C5 antibody (eculizumab), have been shown to inhibit complement safely, and are now being investigated in a variety of clinical conditions. KEY MESSAGES SLE is an autoimmune disorder which targets multiple systems. Complement is centrally involved and plays dual roles in the pathogenesis of SLE. Studies from experimental lupus models and clinical trials support the use of complement-targeted therapy in the treatment of SLE.
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Affiliation(s)
- Lihua Bao
- Section of Nephrology, Department of Medicine, University of Chicago, Chicago, Ill., USA
| | - Patrick N Cunningham
- Section of Nephrology, Department of Medicine, University of Chicago, Chicago, Ill., USA
| | - Richard J Quigg
- Division of Nephrology, University at Buffalo School of Medicine, Buffalo, N.Y., USA
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Liszewski MK, Atkinson JP. Complement regulator CD46: genetic variants and disease associations. Hum Genomics 2015; 9:7. [PMID: 26054645 PMCID: PMC4469999 DOI: 10.1186/s40246-015-0029-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 05/26/2015] [Indexed: 12/23/2022] Open
Abstract
Membrane cofactor protein (MCP; CD46) is an ubiquitously expressed complement regulatory protein that protects host cells from injury by complement. This type-I membrane glycoprotein serves as a cofactor for the serine protease factor I to mediate inactivation of C3b and C4b deposited on host cells. More than 60 disease-associated mutations in MCP have now been identified. The majority of the mutations are linked to a rare thrombotic microangiopathic-based disease, atypical hemolytic uremic syndrome (aHUS), but new putative links to systemic lupus erythematosus, glomerulonephritis, and pregnancy-related disorders among others have also been identified. This review summarizes our current knowledge of disease-associated mutations in this complement inhibitor.
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Affiliation(s)
- M Kathryn Liszewski
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, 660 South Euclid, Saint Louis, MO, 63110, USA.
| | - John P Atkinson
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, 660 South Euclid, Saint Louis, MO, 63110, 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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Masahara H, Nakazawa M, Kawamura E, Eguchi S. Exclusion of influences of ARMS2 polymorphisms on the central visual field in retinitis pigmentosa. Ophthalmologica 2013; 231:51-7. [PMID: 24217333 DOI: 10.1159/000355093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 07/23/2013] [Indexed: 11/19/2022]
Abstract
PURPOSE To investigate the effects of polymorphisms of the age-related maculopathy susceptibility 2 (ARMS2) gene on the central visual field defects in retinitis pigmentosa (RP). SUBJECTS AND METHODS The visual field was evaluated using the 10-2 Swedish Interactive Threshold Algorithm Fast Program and mean deviation (MD) slope, and regression coefficients of average sensitivity of the central 4 points (Cent4) were compared between each genetic subgroup. RESULTS The MD slope (right/left) was as follows: GG, -1.37 ± 2.18/ -0.89 ± 1.15; GT, -0.56 ± 1.40/-0.77 ± 1.04; TT, -0.75 ± 0.64/ -0.38 ± 0.92 dB/year. The Cent4 was as follows: GG, -1.34 ± 2.37/-1.60 ± 3.21; GT, -1.15 ± 2.08/1.07 ± 1.80; TT, -1.20 ± 0.91/-0.65 ± 1.37 dB/year. No significant differences in the degree of progression were observed when comparing groups. CONCLUSIONS These data suggest that polymorphisms of the ARMS2 do not modify the progression of the central field of vision in RP patients.
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Affiliation(s)
- Hidetaka Masahara
- Department of Ophthalmology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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Thompson IA, Liu B, Sen HN, Jiao X, Katamay R, Li Z, Hu M, Hejtmancik F, Nussenblatt RB. Association of complement factor H tyrosine 402 histidine genotype with posterior involvement in sarcoid-related uveitis. Am J Ophthalmol 2013; 155:1068-1074.e1. [PMID: 23497844 DOI: 10.1016/j.ajo.2013.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 01/12/2013] [Accepted: 01/16/2013] [Indexed: 10/27/2022]
Abstract
PURPOSE To determine whether the complement factor H (CFH) tyrosine 402 histidine (Y402H) variant, recently shown to be associated with age-related macular degeneration (AMD) and multifocal choroiditis, is associated with specific ocular sarcoidosis clinical phenotypes in black and white persons. DESIGN Case-control study. METHODS The CFH Y402H polymorphism (rs1061170) was genotyped in 41 subjects with ocular sarcoidosis and 393 control subjects. Allele frequencies in the ocular sarcoidosis cases were compared with controls using chi-square score tests. Genotypic model-based (dominant, recessive, and additive) associations of the rs1061170 allele were tested using multivariate logistic regression. Bayesian information criteria were used to formalize model selection. Genotypes were correlated with disease characteristics and severity of ocular inflammation. RESULTS The C allele (rs1061170) was found in 35% of controls, but occurred with a significantly higher frequency (48.7%) in ocular sarcoidosis cases (odds ratio, 1.72; 95% confidence interval, 1.09 to 2.78; P = .018). Logistic regression demonstrated an association between rs1061170 and ocular sarcoidosis in 2 of 3 genetic models (additive, P = .0078; recessive, P = .0018). Posterior uveitis and panuveitis were overrepresented significantly in cases with the homozygous variant genotype (CC, 91%; P = .047). The population-attributable risk related to this CFH risk variant was 20%. CONCLUSIONS The Y402H polymorphism of CFH seems to be associated with ocular sarcoidosis in black and white persons. Carriage of the CFH Y402H polymorphism in both alleles is associated with an increased risk for posterior uveitis and panuveitis presentation. The prognostic importance of this genotype will require prolonged follow-up studies.
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Foltyn Zadura A, Zipfel PF, Bokarewa MI, Sturfelt G, Jönsen A, Nilsson SC, Hillarp A, Saxne T, Trouw LA, Blom AM. Factor H autoantibodies and deletion of Complement Factor H-Related protein-1 in rheumatic diseases in comparison to atypical hemolytic uremic syndrome. Arthritis Res Ther 2012; 14:R185. [PMID: 22894814 PMCID: PMC3580581 DOI: 10.1186/ar4016] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 08/15/2012] [Indexed: 12/18/2022] Open
Abstract
Introduction Complement activation is involved in rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and atypical hemolytic uremic syndrome (aHUS). Autoantibodies to complement inhibitor factor H (FH), particularly in association with deletions of the gene coding for FH-related protein 1 (CFHR1), are associated with aHUS. Methods Autoantibodies against FH, factor I (FI) and C4b-binding protein (C4BP) were measured by ELISA, while CFHR1 homozygous deletion was determined with Western blotting of sera. Epitopes for FH autoantibodies were mapped using recombinant fragments of FH. Results FH autoantibodies were detected in SLE (6.7%, n = 60, RA patients (16.5%, n = 97 in the Swedish cohort and 9.2%, n = 217 in the Dutch cohort) and thrombosis patients positive for the lupus anticoagulants (LA+) test (9.4%, n = 64) compared with aHUS patients (11.7%, n = 103). In the control groups (n = 354), an average of 4% of individuals were positive for FH autoantibodies. The frequencies observed in both RA cohorts and LA+ patients were statistically significantly higher than in controls. We also found that an average of 15.2% of the FH-autoantibody positive individuals in all studied disease groups had homozygous deficiency of CFHR1 compared with 3.8% of the FH autoantibody negative patients. The levels of FH autoantibodies varied in individual patients over time. FH autoantibodies found in LA+, SLE and RA were directed against several epitopes across FH in contrast to those found in aHUS, which bound mainly to the C-terminus. Autoantibodies against FI and C4BP were detected in some patients and controls but they were not associated with any of the diseases analyzed in this study. Conclusions Autoantibodies against FH are not specific for aHUS but are present at a significant frequency in rheumatic diseases where they could be involved in pathophysiological mechanisms.
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Abstract
The complement system has vital protective functions as a humoral component of the innate immune system and also through interactions with the adaptive immune system; however, when inappropriately activated or regulated, complement can cause inflammation and organ damage, and such processes are involved in the pathogenesis of many inflammatory conditions, not least rheumatic diseases. Furthermore, states of complement deficiency can predispose not only to infections, but also to autoimmune disorders, including rheumatic diseases such as systemic lupus erythematosus. In this Review, the mechanisms behind the pathogenic activities of complement in rheumatic diseases are discussed. Potential approaches to therapeutic intervention that focus on regulating complement activities in these disorders are also considered.
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