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Kirschfink M, Frazer-Abel A, Balogh E, Goseberg S, Weiss N, Prohászka Z. External quality assurance program for diagnostic complement laboratories: evaluation of the results of the past seven years. Front Immunol 2024; 15:1368399. [PMID: 38596685 PMCID: PMC11002221 DOI: 10.3389/fimmu.2024.1368399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 03/07/2024] [Indexed: 04/11/2024] Open
Abstract
Introduction The complement external quality assurance (EQA) program was first organized in 2010 by a group of researchers working in diagnostic complement laboratories. Starting in 2016, INSTAND e.V., a German, non-profit interdisciplinary scientific medical society dedicated to providing expert EQA programs for medical laboratories, started organizing the EQAs for complement diagnostic laboratories together with the same group of experienced scientists and doctors who also work as EQA experts. The aim of the current work is to provide descriptive analysis of the past seven years' complement EQA results and evaluate timeline changes in proficiency testing. Methods Each year, in March and October, blinded samples (normal, pathological) were sent to the participating diagnostic laboratories, where complement parameters were evaluated exactly as in daily routine samples. Since no reference method/target values exist for these parameters, and participants used different units for measurement, the reported results were compared to the stable mean (Algorithm A) of the participants using the same method/measurement units. A reported result was qualified as "passed" if it fell into the 30-50% evaluation/target range around the mean of reported results (depending on the given parameter). Results While the number of participating laboratories has increased in the past years (from around 120 to 347), the number of complement laboratories providing multiple determinations remained mostly unchanged (around 30 worldwide). C3, C4, C1-inhibitor antigen and activity determinations provided the best proficiency results, with >90% passing quotas in the past years, independent of the applied method. Determination of the functional activity of the three activation pathways was good in general, but results showed large variance, especially with the pathological samples. Complement factor C1q and regulators FH and FI are determined by only a few laboratories, with variable outcomes (in general in the 85-90% pass range). Activation products sC5b-9 and Bb were determined in 30 and 10 laboratories, respectively, with typical passing quotas in the 70-90% range, without a clear tendency over the past years. Conclusion With these accumulated data from the past seven years, it is now possible to assess sample-, method-, and evaluation related aspects to further improve proficiency testing and protocolize diagnostic complement determinations.
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Affiliation(s)
- Michael Kirschfink
- Institute of Immunology, University of Heidelberg, Heidelberg, Germany
- Instand eV, Düsseldorf, Germany
| | | | - Emese Balogh
- Department of Pharmaceutics, Semmelweis University, Budapest, Hungary
| | | | | | - Zoltán Prohászka
- Instand eV, Düsseldorf, Germany
- Department of Internal Medicine and Hematology, Füst György Complement Diagnostic Laboratory, Semmelweis University, Budapest, Hungary
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Giang S, Agrawal AK, Oates A. Daratumumab therapy in a pediatric case of C3 nephritic factor-positive proliferative glomerulonephritis with monoclonal IgG deposits. CEN Case Rep 2024:10.1007/s13730-024-00868-0. [PMID: 38517598 DOI: 10.1007/s13730-024-00868-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 03/13/2024] [Indexed: 03/24/2024] Open
Abstract
Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) is an exceedingly rare cause of glomerulonephritis among children for which prognosis is generally poor, with low incidence of remission and high rates of recurrence after transplant. While there are more cases reported in the adult literature, substantial differences in pediatric vs. adult PGNMID render it essential that we further characterize pediatric cases to optimize management. We report the case of a 12-year-old male presenting initially with edema and hypertension who was subsequently diagnosed with IgG3/Kappa-dominant PGNMID. In the absence of any proven therapy and though without a detectable clone, he was empirically treated with daratumumab with positive effect to date. This is the first reported case of daratumumab monotherapy in pediatric PGNMID, as well as the first PGNMID case to detect presence of C3 nephritic factor.
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Affiliation(s)
- Sophia Giang
- Department of Pediatrics, University of California, San Francisco, 550 16th Street, 4th Floor, Mailstop: 3214, San Francisco, CA, 94143, USA.
| | - Anurag K Agrawal
- Department of Pediatrics, University of California, San Francisco, 550 16th Street, 4th Floor, Mailstop: 3214, San Francisco, CA, 94143, USA
| | - Aris Oates
- Department of Pediatrics, University of California, San Francisco, 550 16th Street, 4th Floor, Mailstop: 3214, San Francisco, CA, 94143, USA
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3
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Magno S, Ceccarini G, Corvillo F, Pelosini C, Gilio D, Paoli M, Fornaciari S, Pandolfo G, Sanchez-Iglesias S, Nozal P, Curcio M, Sessa MR, López-Trascasa M, Araújo-Vilar D, Santini F. Clinical Characteristics of Patients With Acquired Partial Lipodystrophy: A Multicenter Retrospective Study. J Clin Endocrinol Metab 2024; 109:e932-e944. [PMID: 38061004 DOI: 10.1210/clinem/dgad700] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Indexed: 02/21/2024]
Abstract
BACKGROUND Barraquer-Simons syndrome (BSS) is a rare, acquired form of lipodystrophy characterized by progressive loss of upper body subcutaneous fat, which affects face, upper limbs, and trunk. The pathogenesis of the disease is not entirely known and may involve autoimmune mechanisms. AIM This study aimed to provide a comprehensive picture of the clinical, immunological, and metabolic features of a large cohort of patients with BSS. Our primary objectives included the validation of existing diagnostic tools, the evaluation of novel diagnostic approaches, and the exploration of potential disease triggers or genetic predispositions. SUBJECTS AND METHODS Twenty-six patients were diagnosed with BSS based on accepted criteria defined by international guidelines. Anthropometric parameters, biochemical tests, organ- and non-organ-specific autoantibodies, HLA status, and screening of the LMNB2 gene were performed. RESULTS Patients were predominantly females (73%); fat loss occurred mostly during childhood (77%) at a median age of 8 years. Among various anthropometric measures, the ratio between the proportion of fat mass in upper limbs and lower limbs showed the best predictive value for diagnosis. A total of 11.5% of patients had diabetes, 34.6% dyslipidemia, and 26.9% hepatic steatosis. Seventy-five percent of children and 50% of adults had C3 hypocomplementemia; 76% of patients were positive for 1 or more autoantibodies. HLA-DRB1 11:03 had higher allelic frequencies compared with the general population. A single variant in the LMNB2 gene was found in 1 patient. CONCLUSION BSS has a childhood onset and is often associated with autoimmune diseases. Skinfold thickness measurements and fat assessment by dual energy X-ray absorptiometry are useful tools to identify the disease. C3 hypocomplementemia and the presence of autoantibodies may be used as additional diagnostic supportive criteria but the prevalence of C3 hypocomplementemia may be lower than previously reported.
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Affiliation(s)
- Silvia Magno
- Obesity and Lipodystrophy Center, Endocrinology Unit, University Hospital of Pisa, Pisa 56124, Italy
| | - Giovanni Ceccarini
- Obesity and Lipodystrophy Center, Endocrinology Unit, University Hospital of Pisa, Pisa 56124, Italy
| | - Fernando Corvillo
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Paseo de la Castellana, Madrid 28046, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Madrid 28046, Spain
| | - Caterina Pelosini
- Obesity and Lipodystrophy Center, Endocrinology Unit, University Hospital of Pisa, Pisa 56124, Italy
- Chemistry and Endocrinology Laboratory, Department of Radiological, Nuclear and Laboratory Medicine, University Hospital of Pisa, Pisa 56124, Italy
| | - Donatella Gilio
- Obesity and Lipodystrophy Center, Endocrinology Unit, University Hospital of Pisa, Pisa 56124, Italy
| | - Melania Paoli
- Chemistry and Endocrinology Laboratory, Department of Radiological, Nuclear and Laboratory Medicine, University Hospital of Pisa, Pisa 56124, Italy
| | - Silvia Fornaciari
- Division of Transfusion Medicine and Transplant Biology, Department of Radiological, Nuclear and Laboratory Medicine, University Hospital of Pisa, Pisa 56124, Italy
| | - Giuseppe Pandolfo
- Department of Economics and Statistics, University of Naples Federico II, Naples 80138, Italy
| | - Sofia Sanchez-Iglesias
- Thyroid and Metabolic Diseases Unit (U.E.T.eM.), Centro Singular de Investigación en Medicina Molecular e Enfermidades Crónicas (CIMUS-IDIS), School of Medicine, Universidad de Santiago de Compostela, Santiago de Compostela 15700, Spain
| | - Pilar Nozal
- Immunology Unit, La Paz University Hospital, Madrid 28046, Spain
| | - Michele Curcio
- Division of Transfusion Medicine and Transplant Biology, Department of Radiological, Nuclear and Laboratory Medicine, University Hospital of Pisa, Pisa 56124, Italy
| | - Maria Rita Sessa
- Chemistry and Endocrinology Laboratory, Department of Radiological, Nuclear and Laboratory Medicine, University Hospital of Pisa, Pisa 56124, Italy
| | - Margarita López-Trascasa
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Paseo de la Castellana, Madrid 28046, Spain
- Department of Medicine, Universidad Autónoma de Madrid, Madrid 28046, Spain
| | - David Araújo-Vilar
- Thyroid and Metabolic Diseases Unit (U.E.T.eM.), Centro Singular de Investigación en Medicina Molecular e Enfermidades Crónicas (CIMUS-IDIS), School of Medicine, Universidad de Santiago de Compostela, Santiago de Compostela 15700, Spain
| | - Ferruccio Santini
- Obesity and Lipodystrophy Center, Endocrinology Unit, University Hospital of Pisa, Pisa 56124, Italy
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Hourcade DE, Mitchell LM. A Monoclonal Antibody That Provides a Model for C3 Nephritic Factors. Monoclon Antib Immunodiagn Immunother 2023; 42:9-14. [PMID: 36853837 PMCID: PMC9983123 DOI: 10.1089/mab.2022.0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 01/17/2023] [Indexed: 03/01/2023] Open
Abstract
Complement is a major innate defense system that protects the intravascular space from microbial invasion. Complement activation results in the assembly of C3 convertases, serine proteases that cleave complement protein C3, generating bioactive fragments C3a and C3b. The complement response is rapid and robust, largely due to a positive feedback regulatory loop mediated by alternative pathway (AP) C3 convertase. C3 nephritic factors (C3NEFs) are autoantibodies that stabilize AP convertase, resulting in uncontrolled C3 cleavage, which, in principle, can promote critical tissue injury similar to that seen in certain renal conditions. Investigations of C3NEFs are hampered by a challenging issue: each C3NEF is derived from a different donor source, and there is no method to compare one C3NEF to another. We have identified a widely available mouse anti-C3 mAb that, similar to many C3NEFs, can stabilize functional AP convertase in a form resistant to decay acceleration by multiple complement regulators. The antibody requires the presence of properdin to confer convertase stability, and hampers the activity of Salp20, a tic salivary protein that accelerates convertase dissociation by displacing properdin from the convertase complex. This mAb can serve as an urgently needed standard for the investigation of C3NEFs. This study also provides novel insights into the dynamics of AP convertase.
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Affiliation(s)
- Dennis E. Hourcade
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lynne M. Mitchell
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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Michels MAHM, Wijnsma KL, Kurvers RAJ, Westra D, Schreuder MF, van Wijk JAE, Bouts AHM, Gracchi V, Engels FAPT, Keijzer-Veen MG, Dorresteijn EM, Volokhina EB, van den Heuvel LPWJ, van de Kar NCAJ. Long-term follow-up including extensive complement analysis of a pediatric C3 glomerulopathy cohort. Pediatr Nephrol 2022; 37:601-12. [PMID: 34476601 DOI: 10.1007/s00467-021-05221-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/06/2021] [Accepted: 07/06/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND C3 glomerulopathy (C3G) is a rare kidney disorder characterized by predominant glomerular depositions of complement C3. C3G can be subdivided into dense deposit disease (DDD) and C3 glomerulonephritis (C3GN). This study describes the long-term follow-up with extensive complement analysis of 29 Dutch children with C3G. METHODS Twenty-nine C3G patients (19 DDD, 10 C3GN) diagnosed between 1992 and 2014 were included. Clinical and laboratory findings were collected at presentation and during follow-up. Specialized assays were used to detect rare variants in complement genes and measure complement-directed autoantibodies and biomarkers in blood. RESULTS DDD patients presented with lower estimated glomerular filtration rate (eGFR). C3 nephritic factors (C3NeFs) were detected in 20 patients and remained detectable over time despite immunosuppressive treatment. At presentation, low serum C3 levels were detected in 84% of all patients. During follow-up, in about 50% of patients, all of them C3NeF-positive, C3 levels remained low. Linear mixed model analysis showed that C3GN patients had higher soluble C5b-9 (sC5b-9) and lower properdin levels compared to DDD patients. With a median follow-up of 52 months, an overall benign outcome was observed with only six patients with eGFR below 90 ml/min/1.73 m2 at last follow-up. CONCLUSIONS We extensively described clinical and laboratory findings including complement features of an exclusively pediatric C3G cohort. Outcome was relatively benign, persistent low C3 correlated with C3NeF presence, and C3GN was associated with higher sC5b-9 and lower properdin levels. Prospective studies are needed to further elucidate the pathogenic mechanisms underlying C3G and guide personalized medicine with complement therapeutics.
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Abdul-Aziz R, Deng R, Liu L, Tarsi S, Waz WR, Wu X. Complete Renal Recovery in Pediatric Patient with C3 Glomerulonephritis: A Case Report. Case Rep Nephrol Dial 2021; 11:261-269. [PMID: 34703825 PMCID: PMC8460949 DOI: 10.1159/000518714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/26/2021] [Indexed: 12/03/2022] Open
Abstract
C3 glomerulonephritis (C3GN) is a rare kidney disease resulting from dysregulation of the alternative complement cascade. Without treatment, approximately 70% of affected children and 30–50% of affected adults will develop worsening of proteinuria and progress to end-stage renal disease within 10 years of diagnosis. Here, we describe a 9-year-old Sudanese girl with no significant past medical history who presented to the Emergency Department with a 2-month history of fatigue, poor oral intake, and worsening facial and lower extremity edema, and subsequently found to have anemia, hypoalbuminemia, microscopic hematuria, and proteinuria. Additional laboratory testing revealed that the patient had low C3, high C3 nephritic factor (C3NeF), and high factor H. Renal function was normal. The diagnosis of C3GN was confirmed by renal biopsy. The patient was treated with ACE inhibitor, mycophenolate mofetil (600 mg per m<sup>2</sup> per dose, every 12 h), in combination with “pulse” methylprednisolone at 30 mg/kg/day IV bolus (maximum 1 g) for 3 consecutive days, followed by 2 months of daily oral prednisolone (2 mg/kg/day) and alternate-day prednisolone weaning from 1 mg/kg to 0.1 mg/kg for additional 12 months. Mycophenolate was continued throughout her treatment course and for maintenance therapy. In response to treatment, anemia, microscopic hematuria, hypoalbuminemia, and proteinuria resolved. Complete complement profile before and at 6 months therapy showed normalization of C3NeF, complement regulatory factor H and C3. This present case provides evidence of the full responsiveness of a rare form of complement dysregulation C3GN to a combination of mycophenolate and corticosteroids. The disease has NOT recurred in >2 years after initial presentation.
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Affiliation(s)
- Rabheh Abdul-Aziz
- Oishei Children's Hospital of Buffalo, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA
| | - Rong Deng
- Oishei Children's Hospital of Buffalo, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA
| | - Lin Liu
- Department of Pathology and Anatomical Sciences, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA
| | - Shauna Tarsi
- Oishei Children's Hospital of Buffalo, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA
| | - Wayne R Waz
- Oishei Children's Hospital of Buffalo, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA
| | - Xiaoyan Wu
- Oishei Children's Hospital of Buffalo, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA
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Abstract
The complement system is a key part of innate immunity. However, if the system becomes dysregulated, damage to healthy host cells can occur, especially to the glomerular cells of the kidney. The convertases of the alternative pathway of the complement system play a crucial role in complement activation. In healthy conditions, their activity is strictly regulated. In patients with diseases caused by complement alternative pathway dysregulation, such as C3 glomerulopathy and atypical hemolytic uremic syndrome, factors can be present in the blood that disturb this delicate balance, leading to convertase overactivity. Such factors include C3 nephritic factors, which are autoantibodies against the C3 convertase that prolong its activity, or genetic variants resulting in a stabilized convertase complex. This chapter describes a method in which the activity and stability of the alternative pathway convertases can be measured to detect aberrant serum factors causing convertase overactivity.
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Affiliation(s)
- Marloes A H M Michels
- Department of Pediatric Nephrology, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Nicole C A J van de Kar
- Department of Pediatric Nephrology, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Elena B Volokhina
- Department of Pediatric Nephrology, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bert L P W J van den Heuvel
- Department of Pediatric Nephrology, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, The Netherlands.
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
- Department of Pediatrics/Pediatric Nephrology, University Hospitals Leuven, Leuven, Belgium.
- Department of Development and Regeneration, University Hospitals Leuven, Leuven, Belgium.
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Defendi F, Thielens NM, Clavarino G, Cesbron JY, Dumestre-Pérard C. The Immunopathology of Complement Proteins and Innate Immunity in Autoimmune Disease. Clin Rev Allergy Immunol 2020; 58:229-51. [PMID: 31834594 DOI: 10.1007/s12016-019-08774-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The complement is a powerful cascade of the innate immunity and also acts as a bridge between innate and acquired immune defence. Complement activation can occur via three distinct pathways, the classical, alternative and lectin pathways, each resulting in the common terminal pathway. Complement activation results in the release of a range of biologically active molecules that significantly contribute to immune surveillance and tissue homeostasis. Several soluble and membrane-bound regulatory proteins restrict complement activation in order to prevent complement-mediated autologous damage, consumption and exacerbated inflammation. The crucial role of complement in the host homeostasis is illustrated by association of both complement deficiency and overactivation with severe and life-threatening diseases. Autoantibodies targeting complement components have been described to alter expression and/or function of target protein resulting in a dysregulation of the delicate equilibrium between activation and inhibition of complement. The spectrum of diseases associated with complement autoantibodies depends on which complement protein and activation pathway are targeted, ranging from autoimmune disorders to kidney and vascular diseases. Nevertheless, these autoantibodies have been identified as differential biomarkers for diagnosis or follow-up of disease only in a small number of clinical conditions. For some autoantibodies, a clear relationship with clinical manifestations has been identified, such as anti-C1q, anti-Factor H, anti-C1 Inhibitor antibodies and C3 nephritic factor. For other autoantibodies, the origin and the functional consequences still remain to be elucidated, questioning about the pathophysiological significance of these autoantibodies, such as anti-mannose binding lectin, anti-Factor I, anti-Factor B and anti-C3b antibodies. The detection of autoantibodies targeting complement components is performed in specialized laboratories; however, there is no consensus on detection methods and standardization of the assays is a real challenge. This review summarizes the current panorama of autoantibodies targeting complement recognition proteins of the classical and lectin pathways, associated proteases, convertases, regulators and terminal components, with an emphasis on autoantibodies clearly involved in clinical conditions.
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Corvillo F, Nozal P, López-Lera A, De Miguel MP, Piñero-Fernández JA, De Lucas R, García-Concepción MD, Beato MJ, Araújo-Vilar D, López-Trascasa M. Evidence of ongoing complement activation on adipose tissue from an 11-year-old girl with Barraquer-Simons syndrome. J Dermatol 2020; 47:1439-1444. [PMID: 32890433 DOI: 10.1111/1346-8138.15570] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 07/28/2020] [Accepted: 07/29/2020] [Indexed: 01/18/2023]
Abstract
Barraquer-Simons syndrome (BSS), a form of acquired partial lipodystrophy, is a rare condition characterized by gradual loss of adipose tissue from the upper body, keeping intact the white adipose tissue of the lower extremities. The etiology of BSS is not well understood, and clinical follow-up studies have not been assessed in these patients. Moreover, no histological studies have been conducted during the active phase of the disease, and complement system activation products have not been sought in the affected areas. The objective of this work was to analyze the clinical, immunological and histological events in an 11-year-old girl with BSS over a 5-year follow-up period. Clinical data were collected during six regular visits for a time period of 5 years. The circulating levels of C3, C3adesArg (a product released upon C3 activation), C4 and immunoglobulins (Ig) were quantified in serum while fat tissue from lipoatrophic areas was examined by immunohistochemical and immunofluorescence approaches. In her regular visits, no clinical or laboratory abnormalities had been observed in the patient, except for the progression of lipoatrophy linked to the C3 hypocomplementemia and the occurrence of C3 nephritic factor. Adipose tissue from the patient showed atrophied and dead adipocytes, an abnormal production of extracellular matrix, and a remarkable accumulation of infiltrating CD68 macrophages and adipocyte precursors (marked by c-Kit positiveness). Simultaneous detection of IgG, C3, C5a and C5b-9 proved the ongoing complement activity and complement-directed injury within the adipose tissue. Our results showed the first evidence that the complement system hyperactivation occurs within the adipose tissue and is linked with fat loss in patients with BSS.
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Affiliation(s)
- Fernando Corvillo
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER U754), Madrid, Spain
| | - Pilar Nozal
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER U754), Madrid, Spain.,Unit of Immunology, La Paz University Hospital, Madrid, Spain
| | - Alberto López-Lera
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER U754), Madrid, Spain
| | - María P De Miguel
- Cell Engineering Laboratory, La Paz University Hospital Research Institute, IdiPAZ, Madrid, Spain
| | | | - Raúl De Lucas
- Departments of, Department of, Dermatology, La Paz University Hospital Madrid, Madrid, Spain
| | | | - María J Beato
- Department of, Pathology, La Paz University Hospital Madrid, Madrid, Spain
| | - David Araújo-Vilar
- Thyroid and Metabolic Diseases Unit (U.E.T.eM.), Centre for Research in Molecular Medicine and Chronic Diseases (CIMUS)-IDIS, University of Santiago de Compostela School of Medicine, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Margarita López-Trascasa
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Madrid, Spain.,Universidad Autónoma de Madrid, Madrid, Spain
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Corvillo F, Ceccarini G, Nozal P, Magno S, Pelosini C, Garrido S, López-Lera A, Moraru M, Vilches C, Fornaciari S, Gabbriellini S, Santini F, Araújo-Vilar D, López-Trascasa M. Immunological features of patients affected by Barraquer-Simons syndrome. Orphanet J Rare Dis 2020; 15:9. [PMID: 31924231 PMCID: PMC6954565 DOI: 10.1186/s13023-019-1292-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 12/29/2019] [Indexed: 01/16/2023] Open
Abstract
Background C3 hypocomplementemia and the presence of C3 nephritic factor (C3NeF), an autoantibody causing complement system over-activation, are common features among most patients affected by Barraquer-Simons syndrome (BSS), an acquired form of partial lipodystrophy. Moreover, BSS is frequently associated with autoimmune diseases. However, the relationship between complement system dysregulation and BSS remains to be fully elucidated. The aim of this study was to provide a comprehensive immunological analysis of the complement system status, autoantibody signatures and HLA profile in BSS. Thirteen subjects with BSS were recruited for the study. The circulating levels of complement components, C3, C4, Factor B (FB) and Properdin (P), as well as an extended autoantibody profile including autoantibodies targeting complement components and regulators were assessed in serum. Additionally, HLA genotyping was carried out using DNA extracted from peripheral blood mononuclear cells. Results C3, C4 and FB levels were significantly reduced in patients with BSS as compared with healthy subjects. C3NeF was the most frequently found autoantibody (69.2% of cases), followed by anti-C3 (38.5%), and anti-P and anti-FB (30.8% each). Clinical data showed high prevalence of autoimmune diseases (38.5%), the majority of patients (61.5%) being positive for at least one of the autoantibodies tested. The HLA allele DRB1*11 was present in 54% of BSS patients, and the majority of them (31%) were positive for *11:03 (vs 1.3% allelic frequency in the general population). Conclusions Our results confirmed the association between BSS, autoimmunity and C3 hypocomplementemia. Moreover, the finding of autoantibodies targeting complement system proteins points to complement dysregulation as a central pathological event in the development of BSS.
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Affiliation(s)
- Fernando Corvillo
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Paseo de la Castellana, 261, 28046, Madrid, Spain. .,Center for Biomedical Network Research on Rare Diseases (CIBERER U754), Madrid, Spain.
| | - Giovanni Ceccarini
- Obesity and Lipodystrophy Centre at the Endocrinology Unit, University Hospital of Pisa, Pisa, Italy
| | - Pilar Nozal
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Paseo de la Castellana, 261, 28046, Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER U754), Madrid, Spain.,Unit of Immunology, La Paz University Hospital, Madrid, Spain
| | - Silvia Magno
- Obesity and Lipodystrophy Centre at the Endocrinology Unit, University Hospital of Pisa, Pisa, Italy
| | - Caterina Pelosini
- Obesity and Lipodystrophy Centre at the Endocrinology Unit, University Hospital of Pisa, Pisa, Italy
| | - Sofía Garrido
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Paseo de la Castellana, 261, 28046, Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER U754), Madrid, Spain.,Unit of Immunology, La Paz University Hospital, Madrid, Spain
| | - Alberto López-Lera
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Paseo de la Castellana, 261, 28046, Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER U754), Madrid, Spain
| | - Manuela Moraru
- Immunogenetics and Histocompatibility, Instituto de Investigación Sanitaria Puerta de Hierro, Madrid, Spain
| | - Carlos Vilches
- Immunogenetics and Histocompatibility, Instituto de Investigación Sanitaria Puerta de Hierro, Madrid, Spain
| | | | | | - Ferruccio Santini
- Obesity and Lipodystrophy Centre at the Endocrinology Unit, University Hospital of Pisa, Pisa, Italy
| | - David Araújo-Vilar
- Thyroid and Metabolic Diseases Unit (U.E.T.eM.), Centro Singular de Investigación en Medicina Molecular e Enfermidades Crónicas (CIMUS-IDIS), School of Medicine, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Margarita López-Trascasa
- Complement Research Group, Hospital La Paz Institute for Health Research (IdiPAZ), La Paz University Hospital, Paseo de la Castellana, 261, 28046, Madrid, Spain.,Universidad Autónoma de Madrid, Madrid, Spain
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11
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Abstract
Glomerulonephritis (GN) refers to a group of renal diseases affecting the glomeruli due to the damage mediated by immunological mechanisms. A large proportion of the disease manifestations are caused by disturbances in the complement system. They can be due to genetic errors, autoimmunity, microbes or abnormal immunoglobulins, like modified IgA or paraproteins. The common denominator in most of the problems is an overactive or misdirected alternative pathway complement activation. An assessment of kidney function, amount of proteinuria and hematuria are crucial elements to evaluate, when glomerulonephritis is suspected. However, the cornerstones of the diagnoses are renal biopsy and careful examination of the complement abnormality. Differential diagnostics between the various forms of GN is not possible based on clinical features, as they may vary greatly. This review describes the known mechanisms of complement dysfunction leading to different forms of primary GN (like IgA glomerulonephritis, dense deposit disease, C3 glomerulonephritis, post-infectious GN, membranous GN) and differences to atypical hemolytic uremic syndrome. It also covers the basic elements of etiology-directed therapy and prognosis of the most common forms of GN. Common principles in the management of GN include treatment of hypertension and reduction of proteinuria, some require immunomodulating treatment. Complement inhibition is an emerging treatment option. A thorough understanding of the basic disease mechanism and a careful follow-up are needed for optimal therapy.
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Affiliation(s)
- Kati Kaartinen
- Department of Nephrology, Abdominal Center, Helsinki University Central Hospital, Helsinki, Finland
| | - Adrian Safa
- Department of Biomedical Sciences, Humanitas University, Milan, Italy; Department of Bacteriology and Immunology, Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Soumya Kotha
- Department of Biomedical Sciences, Humanitas University, Milan, Italy; Department of Bacteriology and Immunology, Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Giorgio Ratti
- Department of Biomedical Sciences, Humanitas University, Milan, Italy; Department of Bacteriology and Immunology, Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Seppo Meri
- Department of Biomedical Sciences, Humanitas University, Milan, Italy; Department of Bacteriology and Immunology, Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; HUSLAB, Helsinki University Central Hospital, Helsinki, Finland.
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12
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Garam N, Prohászka Z, Szilágyi Á, Aigner C, Schmidt A, Gaggl M, Sunder-Plassmann G, Bajcsi D, Brunner J, Dumfarth A, Cejka D, Flaschberger S, Flögelova H, Haris Á, Hartmann Á, Heilos A, Mueller T, Rusai K, Arbeiter K, Hofer J, Jakab D, Sinkó M, Szigeti E, Bereczki C, Janko V, Kelen K, Reusz GS, Szabó AJ, Klenk N, Kóbor K, Kojc N, Knechtelsdorfer M, Laganovic M, Lungu AC, Meglic A, Rus R, Kersnik-Levart T, Macioniene E, Miglinas M, Pawłowska A, Stompór T, Podracka L, Rudnicki M, Mayer G, Romana Rysava, Reiterova J, Saraga M, Tomáš Seeman, Zieg J, Sládková E, Szabó T, Capitanescu A, Stancu S, Tisljar M, Galesic K, Tislér A, Vainumäe I, Windpessl M, Zaoral T, Zlatanova G, Csuka D. C4 nephritic factor in patients with immune-complex-mediated membranoproliferative glomerulonephritis and C3-glomerulopathy. Orphanet J Rare Dis 2019; 14:247. [PMID: 31703608 PMCID: PMC6839100 DOI: 10.1186/s13023-019-1237-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/22/2019] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Acquired or genetic abnormalities of the complement alternative pathway are the primary cause of C3glomerulopathy(C3G) but may occur in immune-complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) as well. Less is known about the presence and role of C4nephritic factor(C4NeF) which may stabilize the classical pathway C3-convertase. Our aim was to examine the presence of C4NeF and its connection with clinical features and with other pathogenic factors. RESULTS One hunfe IC-MPGN/C3G patients were enrolled in the study. C4NeF activity was determined by hemolytic assay utilizing sensitized sheep erythrocytes. Seventeen patients were positive for C4NeF with lower prevalence of renal impairment and lower C4d level, and higher C3 nephritic factor (C3NeF) prevalence at time of diagnosis compared to C4NeF negative patients. Patients positive for both C3NeF and C4NeF had the lowest C3 levels and highest terminal pathway activation. End-stage renal disease did not develop in any of the C4NeF positive patients during follow-up period. Positivity to other complement autoantibodies (anti-C1q, anti-C3) was also linked to the presence of nephritic factors. Unsupervised, data-driven cluster analysis identified a group of patients with high prevalence of multiple complement autoantibodies, including C4NeF. CONCLUSIONS In conclusion, C4NeF may be a possible cause of complement dysregulation in approximately 10-15% of IC-MPGN/C3G patients.
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Affiliation(s)
- Nóra Garam
- Research Laboratory, 3rd Department of Internal Medicine, and MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Kútvölgyi St 4, Budapest, H-1125, Hungary
| | - Zoltán Prohászka
- Research Laboratory, 3rd Department of Internal Medicine, and MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Kútvölgyi St 4, Budapest, H-1125, Hungary.
| | - Ágnes Szilágyi
- Research Laboratory, 3rd Department of Internal Medicine, and MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Kútvölgyi St 4, Budapest, H-1125, Hungary
| | - Christof Aigner
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Alice Schmidt
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Martina Gaggl
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Gere Sunder-Plassmann
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Dóra Bajcsi
- 1st Department of Internal Medicine, University of Szeged, Szeged, Hungary
| | - Jürgen Brunner
- Department of Pediatrics, Medical University of Innsbruck, Innsbruck, Austria
| | - Alexandra Dumfarth
- Department of Medicine III: Nephrology, Transplant Medicine and Rheumatology, Geriatric Department, Ordensklinikum Linz - Elisabethinen, Linz, Austria
| | - Daniel Cejka
- Department of Medicine III: Nephrology, Transplant Medicine and Rheumatology, Geriatric Department, Ordensklinikum Linz - Elisabethinen, Linz, Austria
| | | | - Hana Flögelova
- Division of Nephrology, Department of Pediatrics, Faculty of Medicine, Palacky University and Faculty Hospital in Olomouc, Moravia, Czech Republic
| | - Ágnes Haris
- Department of Nephrology, Szent Margit Hospital, Budapest, Hungary
| | - Ágnes Hartmann
- Department of Pediatrics, University of Pécs, Pécs, Hungary
| | - Andreas Heilos
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Nephrology and Gastroenterology, Medical University of Vienna, Vienna, Austria
| | - Thomas Mueller
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Nephrology and Gastroenterology, Medical University of Vienna, Vienna, Austria
| | - Krisztina Rusai
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Nephrology and Gastroenterology, Medical University of Vienna, Vienna, Austria
| | - Klaus Arbeiter
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Nephrology and Gastroenterology, Medical University of Vienna, Vienna, Austria
| | - Johannes Hofer
- Department of Pediatrics, Medical University of Innsbruck, Innsbruck, Austria
- Institute of Neurology of Senses and Language, Hospital of St John of God, Linz, Austria
- Research Institute for Developmental Medicine, Johannes Kepler University Linz, Linz, Austria
| | - Dániel Jakab
- Department of Pediatrics, University of Szeged, Szeged, Hungary
| | - Mária Sinkó
- Department of Pediatrics, University of Szeged, Szeged, Hungary
| | - Erika Szigeti
- Department of Pediatrics, University of Szeged, Szeged, Hungary
| | - Csaba Bereczki
- Department of Pediatrics, University of Szeged, Szeged, Hungary
| | | | - Kata Kelen
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - György S Reusz
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Attila J Szabó
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Nóra Klenk
- FMC Center of Dialysis, Miskolc, Hungary
| | | | - Nika Kojc
- Institute of Pathology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | | | - Mario Laganovic
- Department of Nephrology, Arterial Hypertension, Dialysis and Transplantation, University Hopital Center Zagreb, School of Medicine University of Zagreb, Zagreb, Croatia
| | | | - Anamarija Meglic
- Department of Pediatric Nephrology, Division of Pediatrics, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Rina Rus
- Department of Pediatric Nephrology, Division of Pediatrics, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Tanja Kersnik-Levart
- Department of Pediatric Nephrology, Division of Pediatrics, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Ernesta Macioniene
- Nephrology Center, Santaros Klinikos, Medical Faculty, Vilnius University, Vilnius, Lithuania
| | - Marius Miglinas
- Nephrology Center, Santaros Klinikos, Medical Faculty, Vilnius University, Vilnius, Lithuania
| | - Anna Pawłowska
- Department of Nephrology, Hypertension and Internal Medicine, School of Medicine, Collegium Medicum, University of Warmia and Mazury, Olsztyn, Poland
| | - Tomasz Stompór
- Department of Nephrology, Hypertension and Internal Medicine, School of Medicine, Collegium Medicum, University of Warmia and Mazury, Olsztyn, Poland
| | | | - Michael Rudnicki
- Dept. of Internal Medicine IV - Nephrology and Hypertension, Medical University Innsbruck, Innsbruck, Austria
| | - Gert Mayer
- Dept. of Internal Medicine IV - Nephrology and Hypertension, Medical University Innsbruck, Innsbruck, Austria
| | - Romana Rysava
- Nephrology Clinic, 1st Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Jana Reiterova
- Nephrology Clinic, 1st Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Marijan Saraga
- Department of Pathology, University Hospital Split University of Split, School of Medicine, Split, Croatia
| | - Tomáš Seeman
- Department of Pediatrics, 2nd Faculty of Medicine, Charles University Prague, University Hospital Motol, Prague, Czech Republic
| | - Jakub Zieg
- Department of Pediatrics, 2nd Faculty of Medicine, Charles University Prague, University Hospital Motol, Prague, Czech Republic
| | - Eva Sládková
- Department of Pediatrics, Charles University in Prague, Faculty of Medicine in Pilsen, Prague, Czech Republic
| | - Tamás Szabó
- Department of Pediatrics, University of Debrecen, Debrecen, Hungary
| | | | - Simona Stancu
- Carol Davila Nephrology Hospital, Bucharest, Romania
| | - Miroslav Tisljar
- Department of Nephrology, Dubrava University Hospital, Zagreb, Croatia
| | - Kresimir Galesic
- Department of Nephrology, Dubrava University Hospital, Zagreb, Croatia
| | - András Tislér
- 1st Department of Internal Medicine, Semmelweis University, Budapest, Hungary
| | - Inga Vainumäe
- Department of Pathology of Tartu University Hospital, Tartu, Estonia
| | - Martin Windpessl
- Internal Medicine IV, Section of Nephrology, Klinikum Wels-Grieskirchen, Wels, Austria
| | - Tomas Zaoral
- Department of Pediatrics, University Hospital and Faculty of Medicine Ostrava, Ostrava, Czech Republic
| | - Galia Zlatanova
- University Children's Hospital Medical University, Sofia, Bulgaria
| | - Dorottya Csuka
- Research Laboratory, 3rd Department of Internal Medicine, and MTA-SE Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Kútvölgyi St 4, Budapest, H-1125, Hungary
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13
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Michels MAHM, van de Kar NCAJ, van den Bos RM, van der Velden TJAM, van Kraaij SAW, Sarlea SA, Gracchi V, Oosterveld MJS, Volokhina EB, van den Heuvel LPWJ. Novel Assays to Distinguish Between Properdin-Dependent and Properdin-Independent C3 Nephritic Factors Provide Insight Into Properdin-Inhibiting Therapy. Front Immunol 2019; 10:1350. [PMID: 31263464 PMCID: PMC6590259 DOI: 10.3389/fimmu.2019.01350] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 05/28/2019] [Indexed: 01/01/2023] Open
Abstract
C3 glomerulopathy (C3G) is an umbrella classification for severe renal diseases characterized by predominant staining for complement component C3 in the glomeruli. The disease is caused by a dysregulation of the alternative pathway (AP) of the complement system. In more than half of C3G patients C3 nephritic factors (C3NeFs) are found. These autoantibodies bind to the AP C3 convertase, prolonging its activity. C3NeFs can be dependent or independent of the complement regulator properdin for their convertase-stabilizing function. However, studies to determine the properdin-dependency of C3NeFs are rare and not part of routine patient workup. Until recently, only supportive treatments for C3G were available. Complement-directed therapies are now being investigated. We hypothesized that patients with properdin-dependent C3NeFs may benefit from properdin-inhibiting therapy to normalize convertase activity. Therefore, in this study we validated two methods to distinguish between properdin-dependent and properdin-independent C3NeFs. These methods are hemolytic assays for measuring convertase activity and stability in absence of properdin. The first assay assesses convertase stabilization by patient immunoglobulins in properdin-depleted serum. The second assay measures convertase stabilization directly in patient serum supplemented with the properdin-blocking agent Salp20. Blood samples from 13 C3NeF-positive C3G patients were tested. Three patients were found to have properdin-dependent C3NeFs, whereas the C3NeF activity of the other ten patients was independent of properdin. The convertase-stabilizing activity in the samples of the patients with properdin-dependent C3NeFs disappeared in absence of properdin. These data indicate that inhibition of properdin in patients with properdin-dependent C3NeFs can normalize convertase activity and could represent a novel therapy for normalizing AP hyperactivity. Our assays provide a tool for identifying C3G patients who may benefit from properdin-inhibiting therapy and can be incorporated into standard C3G laboratory investigations.
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Affiliation(s)
- Marloes A H M Michels
- Department of Pediatric Nephrology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Nijmegen, Netherlands
| | - Nicole C A J van de Kar
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children's Hospital, Nijmegen, Netherlands
| | - Ramon M van den Bos
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Thea J A M van der Velden
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children's Hospital, Nijmegen, Netherlands
| | - Sanne A W van Kraaij
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Sebastian A Sarlea
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children's Hospital, Nijmegen, Netherlands
| | - Valentina Gracchi
- Department of Pediatric Nephrology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Michiel J S Oosterveld
- Department of Pediatric Nephrology, Emma Children's Hospital, Amsterdam University Medical Center, Amsterdam, Netherlands
| | - Elena B Volokhina
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children's Hospital, Nijmegen, Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Lambertus P W J van den Heuvel
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children's Hospital, Nijmegen, Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Pediatrics/Pediatric Nephrology and Department of Development and Regeneration, University Hospitals Leuven, Leuven, Belgium
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14
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Corvillo F, Akinci B. An overview of lipodystrophy and the role of the complement system. Mol Immunol 2019; 112:223-232. [PMID: 31177059 DOI: 10.1016/j.molimm.2019.05.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 05/28/2019] [Accepted: 05/29/2019] [Indexed: 12/19/2022]
Abstract
The complement system is a major component of innate immunity playing essential roles in the destruction of pathogens, the clearance of apoptotic cells and immune complexes, the enhancement of phagocytosis, inflammation, and the modulation of adaptive immune responses. During the last decades, numerous studies have shown that the complement system has key functions in the biology of certain tissues. For example, complement contributes to normal brain and embryonic development and to the homeostasis of lipid metabolism. However, the complement system is subjected to the effective balance between activation-inactivation to maintain complement homeostasis and to prevent self-injury to cells or tissues. When this control is disrupted, serious pathologies eventually develop, such as C3 glomerulopathy, autoimmune conditions and infections. Another heterogeneous group of ultra-rare diseases in which complement abnormalities have been described are the lipodystrophy syndromes. These diseases are characterized by the loss of adipose tissue throughout the entire body or partially. Complement over-activation has been reported in most of the patients with acquired partial lipodystrophy (also called Barraquer-Simons Syndrome) and in some cases of the generalized variety of the disease (Lawrence Syndrome). Even so, the mechanism through which the complement system induces adipose tissue abnormalities remains unclear. This review focuses on describing the link between the complement system and certain forms of lipodystrophy. In addition, we present an overview regarding the clinical presentation, differential diagnosis, classification, and management of patients with lipodystrophy associated with complement abnormalities.
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Affiliation(s)
- F Corvillo
- Complement Research Group, La Paz University Hospital Research Institute (IdiPAZ), La Paz University Hospital, Madrid, Spain; Center for Biomedical Network Research on Rare Diseases (CIBERER U754), Madrid, Spain.
| | - B Akinci
- Division of Endocrinology, Department of Internal Medicine, Dokuz Eylul University, Izmir, Turkey; Brehm Center for Diabetes Research, Division of Metabolism, Endocrinology & Diabetes, Department of Internal Medicine, University of Michigan, 1000 Wall Street, Room 5313, Ann Arbor, MI, 48105, USA
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15
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Michels MAHM, van de Kar NCAJ, Okrój M, Blom AM, van Kraaij SAW, Volokhina EB, van den Heuvel LPWJ. Overactivity of Alternative Pathway Convertases in Patients With Complement-Mediated Renal Diseases. Front Immunol 2018; 9:612. [PMID: 29670616 PMCID: PMC5893837 DOI: 10.3389/fimmu.2018.00612] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 03/12/2018] [Indexed: 01/06/2023] Open
Abstract
Overactivation of the alternative pathway of the complement system is associated with the renal diseases atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy (C3G). C3 nephritic factors (C3NeF) play an important role in C3G pathogenesis by stabilizing the key enzymatic complex of complement, the C3 convertase. However, the reliability of assays detecting these autoantibodies is limited. Therefore, in this study, we validated and optimized a prototype hemolytic method for robust detection and characterization of factors causing convertase overactivity in large patient cohorts. The assay assesses convertase activity directly in the physiological milieu of serum and therefore is not restricted to detection of stabilizing autoantibodies such as C3NeF but may also reveal genetic variants resulting in prolonged convertase activity. We first defined clear cutoff values based on convertase activity in healthy controls. Next, we evaluated 27 C3G patient samples and found 16 positive for prolonged convertase activity, indicating the presence of factors influencing convertase stability. In three patients, the overactive convertase profile was persistent over disease course while in another patient the increased stability normalized in remission. In all these four patients, the convertase-stabilizing activity resided in the purified immunoglobulin (Ig) fraction, demonstrating the autoantibody nature. By contrast, the Igs of a familial aHUS patient carrying the complement factor B mutation p.Lys323Glu did not reveal convertase stabilization. However, in serum prolonged convertase activity was observed and segregated with the mutation in both affected and unaffected family members. In conclusion, we present a robust and reliable method for the detection, characterization, and evaluation over time of factors prolonging convertase activity (C3NeF or certain mutations) in patient cohorts. This assay may provide new insights in disease pathogenesis and may contribute to the development of more personalized treatment strategies.
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Affiliation(s)
- Marloes A H M Michels
- Department of Pediatric Nephrology, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, Netherlands
| | - Nicole C A J van de Kar
- Department of Pediatric Nephrology, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, Netherlands
| | - Marcin Okrój
- Department of Medical Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
| | - Anna M Blom
- Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Sanne A W van Kraaij
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Elena B Volokhina
- Department of Pediatric Nephrology, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Lambertus P W J van den Heuvel
- Department of Pediatric Nephrology, Radboud Institute for Molecular Life Sciences, Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Pediatrics/Pediatric Nephrology and Department of Development and Regeneration, University Hospitals Leuven, Leuven, Belgium
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16
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Yurova VA, Bobrova LA, Kozlovskaya NL, Korotchaeva YV, Serova AG, Kozlov LV, Andina SS, Demyanova KA, Kuchieva AM, Roshchupkina SV. [Changes in the complement system in membranoproliferative glomerulonephritis]. TERAPEVT ARKH 2017; 89:69-77. [PMID: 28745692 DOI: 10.17116/terarkh201789669-77] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
AIM To compare the clinical manifestations membranoproliferative glomerulonephritis (MPGN) in its idiopathic variant, lupus nephritis (LN), and C3 glomerulopathy (C3-GP), by comparing them with changes in the complement system. SUBJECTS AND METHODS The clinic of nephrology followed up 42 patients with different types of MPGN in 2013 to 2015. The study included 35 patients divided into 3 groups: 1) 8 patients with C3-GP, 2) 13 with idiopathic MPGN; 3) 14 with Class IV LN. The investigators studied the blood and urine levels of components and markers for activation of the classical and alternative pathways (C3 and C4, С3а, C5a, CFH, CFB, and CFD) of the terminal complement complex (TCC). RESULTS The detection rate of C3-GP was 19%. The patients with C3-GP were noted to have the lowest blood concentration of S3 and the highest urinary level of С3а, C5a, TCC, CFH, CFB, and CFD. C3 nephritic factor was detected in 2 patients from the C3-GP (dense deposit disease) group. CONCLUSION Alternative complement pathway dysregulation caused by genetic or autoimmune factors plays a leading role in the pathogenesis of C3-GP.
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Affiliation(s)
- V A Yurova
- I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia, Moscow, Russia
| | - L A Bobrova
- I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia, Moscow, Russia
| | - N L Kozlovskaya
- I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia, Moscow, Russia
| | - Yu V Korotchaeva
- I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia, Moscow, Russia
| | - A G Serova
- I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia, Moscow, Russia
| | - L V Kozlov
- G.N.Gabrichevsky Moscow Research Institute of Epidemiology and Microbiology, Russian Federal Service for Supervision of Consumer Rights Protection and Human Welfare, Moscow, Russia
| | - S S Andina
- G.N.Gabrichevsky Moscow Research Institute of Epidemiology and Microbiology, Russian Federal Service for Supervision of Consumer Rights Protection and Human Welfare, Moscow, Russia
| | - K A Demyanova
- I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia, Moscow, Russia
| | - A M Kuchieva
- I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia, Moscow, Russia
| | - S V Roshchupkina
- I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia, Moscow, Russia
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17
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Levy Erez D, Meyers KE, Sullivan KE. C3 nephritic factors: A changing landscape. J Allergy Clin Immunol 2017; 140:57-59. [PMID: 28322851 DOI: 10.1016/j.jaci.2017.02.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 02/14/2017] [Accepted: 02/24/2017] [Indexed: 10/20/2022]
Affiliation(s)
- Daniella Levy Erez
- Division of Nephrology, Children's Hospital of Philadelphia, Philadelphia, Pa; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa.
| | - Kevin E Meyers
- Division of Nephrology, Children's Hospital of Philadelphia, Philadelphia, Pa; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Kathleen E Sullivan
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pa; Division of Allergy and Immunology, Children's Hospital of Philadelphia, Philadelphia, Pa
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Bettoni S, Bresin E, Remuzzi G, Noris M, Donadelli R. Insights into the Effects of Complement Factor H on the Assembly and Decay of the Alternative Pathway C3 Proconvertase and C3 Convertase. J Biol Chem 2016; 291:8214-30. [PMID: 26903516 DOI: 10.1074/jbc.m115.693119] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Indexed: 12/12/2022] Open
Abstract
The activated fragment of C3 (C3b) and factor B form the C3 proconvertase (C3bB), which is cleaved by factor D to C3 convertase (C3bBb). Older studies (Conrad, D. H., Carlo, J. R., and Ruddy, S. (1978)J. Exp. Med.147, 1792-1805; Pangburn, M. K., and Müller-Eberhard, H. J. (1978)Proc. Natl. Acad. Sci. U.S.A.75, 2416-2420; Kazatchkine, M. D., Fearon, D. T., and Austen, K. F. (1979)J. Immunol.122, 75-81) indicated that the complement alternative pathway regulator factor H (FH) competes with factor B for C3b binding; however, the capability of FH to prevent C3bB assembly has not been formally investigated. Moreover, in the few published studies FH did not favor C3bB dissociation. Whether FH may affect C3bBb formation from C3bB is unknown. We set up user-friendly assays based on combined microplate/Western blotting techniques that specifically detect either C3bB or C3bBb, with the aim of investigating the effect of FH on C3bB assembly and decay and C3bBb formation and decay. We document that FH does not affect C3bB assembly, indicating that FH does not efficiently compete with factor B for C3b binding. We also found that FH does not dissociate C3bB. FH showed a strong C3bBb decay-accelerating activity, as reported previously, and also exerted an apparent inhibitory effect on C3bBb formation. The latter effect was not fully attributable to a rapid FH-mediated dissociation of C3bBb complexes, because blocking decay with properdin and C3 nephritic factor did not restore C3bBb formation. FH almost completely prevented release of the smaller cleavage subunit of FB (Ba), without modifying the amount of C3bB complexes, suggesting that FH inhibits the conversion of C3bB to C3bBb. Thus, the inhibitory effect of FH on C3bBb formation is likely the sum of inhibition of C3bB conversion to C3bBb and of C3bBb decay acceleration. Further studies are required to confirm these findings in physiological cell-based settings.
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Affiliation(s)
- Serena Bettoni
- From the IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, 24020 Ranica, Bergamo
| | - Elena Bresin
- From the IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, 24020 Ranica, Bergamo
| | - Giuseppe Remuzzi
- From the IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, 24020 Ranica, Bergamo, the Azienda Ospedaliera Papa Giovanni XXIII, Unit of Nephrology and Dialysis, 24127 Bergamo, and the Department of Biomedical and Clinical Sciences, University of Milan, 20157 Milan, Italy
| | - Marina Noris
- From the IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, 24020 Ranica, Bergamo,
| | - Roberta Donadelli
- From the IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, 24020 Ranica, Bergamo
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Corvillo F, Bravo García-Morato M, Nozal P, Garrido S, Tortajada A, Rodríguez de Córdoba S, López-Trascasa M. Serum properdin consumption as a biomarker of C5 convertase dysregulation in C3 glomerulopathy. Clin Exp Immunol 2016; 184:118-25. [PMID: 26660535 DOI: 10.1111/cei.12754] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 12/03/2015] [Accepted: 12/03/2015] [Indexed: 12/11/2022] Open
Abstract
Properdin (P) stabilizes the alternative pathway (AP) convertases, being the only known positive regulator of the complement system. In addition, P is a pattern recognition molecule able to initiate directly the AP on non-self surfaces. Although P deficiencies have long been known to be associated with Neisseria infections and P is often found deposited at sites of AP activation and tissue injury, the potential role of P in the pathogenesis of complement dysregulation-associated disorders has not been studied extensively. Serum P levels were measured in 49 patients with histological and clinical evidence of C3 glomerulopathy (C3G). Patients were divided into two groups according to the presence or absence of C3 nephritic factor (C3NeF), an autoantibody that stabilizes the AP C3 convertase. The presence of this autoantibody results in a significant reduction in circulating C3 (P < 0·001) and C5 levels (P < 0·05), but does not alter factor B, P and sC5b-9 levels. Interestingly, in our cohort, serum P levels were low in 17 of the 32 C3NeF-negative patients. This group exhibited significant reduction of C3 (P < 0·001) and C5 (P < 0·001) and increase of sC5b-9 (P < 0·001) plasma levels compared to the control group. Also, P consumption was correlated significantly with C3 (r = 0·798, P = 0·0001), C5 (r = 0·806, P < 0·0001), sC5b-9 (r = -0·683, P = 0·043) and a higher degree of proteinuria (r = -0·862, P = 0·013). These results illustrate further the heterogeneity among C3G patients and suggest that P serum levels could be a reliable clinical biomarker to identify patients with underlying surface AP C5 convertase dysregulation.
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Affiliation(s)
- F Corvillo
- Unidad de Inmunología, IdiPAZ, Hospital Universitario La Paz, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER U754), Madrid, Spain
| | | | - P Nozal
- Unidad de Inmunología, IdiPAZ, Hospital Universitario La Paz, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER U754), Madrid, Spain
| | - S Garrido
- Unidad de Inmunología, IdiPAZ, Hospital Universitario La Paz, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER U754), Madrid, Spain
| | - A Tortajada
- Centro De Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain (CIB-CSIC), Centro de Investigación Biomédica en Red de Enfermedades Raras (CBERER U738), Madrid, Spain
| | - S Rodríguez de Córdoba
- Centro De Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain (CIB-CSIC), Centro de Investigación Biomédica en Red de Enfermedades Raras (CBERER U738), Madrid, Spain
| | - M López-Trascasa
- Unidad de Inmunología, IdiPAZ, Hospital Universitario La Paz, Madrid, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER U754), Madrid, Spain
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Oosterveld MJS, Garrelfs MR, Hoppe B, Florquin S, Roelofs JJTH, van den Heuvel LP, Amann K, Davin JC, Bouts AHM, Schriemer PJ, Groothoff JW. Eculizumab in Pediatric Dense Deposit Disease. Clin J Am Soc Nephrol 2015; 10:1773-82. [PMID: 26316621 DOI: 10.2215/cjn.01360215] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 07/01/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Dense deposit disease (DDD), a subtype of C3 glomerulopathy, is a rare disease affecting mostly children. Treatment options are limited. Debate exists whether eculizumab, a monoclonal antibody against complement factor C5, is effective in DDD. Reported data are scarce, especially in children. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS The authors analyzed clinical and histologic data of five pediatric patients with a native kidney biopsy diagnosis of DDD. Patients received eculizumab as therapy of last resort for severe nephritic or nephrotic syndrome with alternative pathway complement activation; this therapy was given only when the patients had not or only marginally responded to immunosuppressive therapy. Outcome measures were kidney function, proteinuria, and urine analysis. RESULTS In all, seven disease episodes were treated with eculizumab (six episodes of severe nephritic syndrome [two of which required dialysis] and one nephrotic syndrome episode). Median age at treatment start was 8.4 (range, 5.9-13) years. For three treatment episodes, eculizumab was the sole immunosuppressive treatment. In all patients, both proteinuria and renal function improved significantly within 12 weeks of treatment (median urinary protein-to-creatinine ratio of 8.5 [range, 2.2-17] versus 1.1 [range, 0.2-2.0] g/g, P<0.005, and eGFR of 58 [range, 17-114] versus 77 [range, 50-129] ml/min per 1.73 m(2), P<0.01). A striking finding was the disappearance of leukocyturia within 1 week after the first eculizumab dose in all five episodes with leukocyturia at treatment initiation. CONCLUSIONS In this case series of pediatric patients with DDD, eculizumab treatment was associated with reduction in proteinuria and increase in eGFR. Leukocyturia resolved within 1 week of initiation of eculizumab treatment. These results underscore the need for a randomized trial of eculizumab in DDD.
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Affiliation(s)
| | | | - Bernd Hoppe
- Department of Pediatrics, Division of Pediatric Nephrology, University Hospital Bonn, Bonn, Germany
| | - Sandrine Florquin
- Department of Pathology, Emma Children's Hospital/Academic Medical Center, Amsterdam, The Netherlands
| | - Joris J T H Roelofs
- Department of Pathology, Emma Children's Hospital/Academic Medical Center, Amsterdam, The Netherlands
| | - L P van den Heuvel
- Department of Pediatric Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands; and
| | - Kerstin Amann
- Department of Pathology, University Hospital Erlangen, Erlangen, Germany
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Zipfel PF, Skerka C, Chen Q, Wiech T, Goodship T, Johnson S, Fremeaux-Bacchi V, Nester C, de Córdoba SR, Noris M, Pickering M, Smith R. The role of complement in C3 glomerulopathy. Mol Immunol 2015; 67:21-30. [PMID: 25929733 DOI: 10.1016/j.molimm.2015.03.012] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 03/09/2015] [Accepted: 03/10/2015] [Indexed: 12/12/2022]
Abstract
C3 glomerulopathy describes a spectrum of disorders with glomerular pathology associated with C3 cleavage product deposition and with defective complement action and regulation (Fakhouri et al., 2010; Sethi et al., 2012b). Kidney biopsies from these patients show glomerular accumulation or deposition of C3 cleavage fragments, but no or minor deposition of immunoglobulins (Appel et al., 2005; D'Agati and Bomback, 2012; Servais et al., 2007; Sethi and Fervenza, 2011). At present the current situation asks for a better definition of the underlining disease mechanisms, for precise biomarkers, and for a treatment for this disease. The complement system is a self activating and propelling enzymatic cascade type system in which inactive, soluble plasma components are activated spontaneously and lead into an amplification loop (Zipfel and Skerka, 2009). Activation of the alternative pathway is spontaneous, occurs by default, and cascade progression leads to amplification by complement activators. The system however is self-controlled by multiple regulators and inhibitors, like Factor H that control cascade progression in fluid phase and on surfaces. The activated complement system generates a series of potent effector components and activation products, which damage foreign-, as well as modified self cells, recruit innate immune cells to the site of action, coordinate inflammation and the response of the adaptive immune system in form of B cells and T lymphocytes (Kohl, 2006; Medzhitov and Janeway, 2002; Ogden and Elkon, 2006; Carroll, 2004; Kemper and Atkinson, 2007; Morgan, 1999; Muller-Eberhard, 1986; Ricklin et al., 2010). Complement controls homeostasis and multiple reactions in the vertebrate organism including defense against microbial infections (Diaz-Guillen et al., 1999; Mastellos and Lambris, 2002; Nordahl et al., 2004; Ricklin et al., 2010). In consequence defective control of the spontaneous self amplifying cascade or regulation is associated with numerous human disorders (Ricklin and Lambris, 2007; Skerka and Zipfel, 2008; Zipfel et al., 2006). Understanding the exact action and regulation of this sophisticated homeotic cascade system is relevant to understand disease pathology of various complement associated human disorders. Furthermore this knowledge is relevant for a better diagnosis and appropriate therapy. At present diagnosis of C3 glomerulopathy is primarily based on the kidney biopsy, and histological, immmunohistological and electron microscopical evaluation (D'Agati and Bomback, 2012; Fakhouri et al., 2010; Medjeral-Thomas et al., 2014a,b; Sethi et al., 2012b). The challenge is to define the actual cause of the diverse glomerular changes or damages, to define how C3 deposition results in the reported glomerular changes, the location of the cell damage and the formation of deposits.
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Affiliation(s)
- Peter F Zipfel
- Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany; Friedrich Schiller University Jena, Germany.
| | - Christine Skerka
- Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Qian Chen
- Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Thorsten Wiech
- Institute for Pathology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Tim Goodship
- Institute of Human Genetics, University of Newcastle upon Tyne, United Kingdom
| | - Sally Johnson
- Institute of Human Genetics, University of Newcastle upon Tyne, United Kingdom
| | - Veronique Fremeaux-Bacchi
- Assistance Publique-Hopitaux de Paris, Hospital European Georges-Pompidou and INSERM UMRS 1138, "Complement and Diseases" Team, Cordelier Research Center, Paris, France
| | - Clara Nester
- University of Iowa Carver College of Medicine, Otolaryngology, Iowa City, IA 52242, USA
| | - Santiago Rodríguez de Córdoba
- Departamento de Medicina Celular y Molecular, and Ciber de Enfermedades Raras, Centro de Investigaciones Biológicas, Ramiro de Maeztu 9, 28040 Madrid, Spain
| | - Marina Noris
- Mario Negri Institute for Pharmacological Research, Ranica, Bergamo, Italy
| | | | - Richard Smith
- University of Iowa Carver College of Medicine, Otolaryngology, Iowa City, IA 52242, USA
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