1
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Hallam TM, Andreadi A, Sharp SJ, Brocklebank V, Gardenal E, Dreismann A, Lotery AJ, Marchbank KJ, Harris CL, Jones AV, Kavanagh D. Comprehensive functional characterization of complement factor I rare variant genotypes identified in the SCOPE geographic atrophy cohort. J Biol Chem 2024; 300:107452. [PMID: 38852887 PMCID: PMC11277764 DOI: 10.1016/j.jbc.2024.107452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 06/11/2024] Open
Abstract
Rare variants (RVs) in the gene encoding the regulatory enzyme complement factor I (CFI; FI) that reduce protein function or levels increase age-related macular degeneration risk. A total of 3357 subjects underwent screening in the SCOPE natural history study for geographic atrophy secondary to age-related macular degeneration, including CFI sequencing and serum FI measurement. Eleven CFI RV genotypes that were challenging to categorize as type I (low serum level) or type II (normal serum level, reduced enzymatic function) were characterized in the context of pure FI protein in C3b and C4b fluid phase cleavage assays and a novel bead-based functional assay (BBFA) of C3b cleavage. Four variants predicted or previously characterized as benign were analyzed by BBFA for comparison. In all, three variants (W51S, C67R, and I370T) resulted in low expression. Furthermore, four variants (P64L, R339Q, G527V, and P528T) were identified as being highly deleterious with IC50s for C3b breakdown >1 log increased versus the WT protein, while two variants (K476E and R474Q) were ∼1 log reduced in function. Meanwhile, six variants (P50A, T203I, K441R, E548Q, P553S, and S570T) had IC50s similar to WT. Odds ratios and BBFA IC50s were positively correlated (r = 0.76, p < 0.01), while odds ratios versus combined annotation dependent depletion (CADD) scores were not (r = 0.43, p = 0.16). Overall, 15 CFI RVs were functionally characterized which may aid future patient stratification for complement-targeted therapies. Pure protein in vitro analysis remains the gold standard for determining the functional consequence of CFI RVs.
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Affiliation(s)
- Thomas M Hallam
- Gyroscope Therapeutics Limited, A Novartis Company, London, UK.
| | - Anneliza Andreadi
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK; National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Scott J Sharp
- Gyroscope Therapeutics Limited, A Novartis Company, London, UK
| | - Vicky Brocklebank
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK; National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | | | - Anna Dreismann
- Gyroscope Therapeutics Limited, A Novartis Company, London, UK
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University Hospital Southampton, University of Southampton, Southampton, UK
| | - Kevin J Marchbank
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK; National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Claire L Harris
- Gyroscope Therapeutics Limited, A Novartis Company, London, UK; Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Amy V Jones
- Gyroscope Therapeutics Limited, A Novartis Company, London, UK
| | - David Kavanagh
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK; National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK; Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK.
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2
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Gerogianni A, Baas LM, Sjöström DJ, van de Kar NCAJ, Pullen M, van de Peppel SJ, Nilsson PH, van den Heuvel LP. Functional evaluation of complement factor I variants by immunoassays and SDS-PAGE. Front Immunol 2023; 14:1279612. [PMID: 37954579 PMCID: PMC10639126 DOI: 10.3389/fimmu.2023.1279612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Accepted: 10/16/2023] [Indexed: 11/14/2023] Open
Abstract
Factor I (FI) is an essential regulator of the complement system. Together with co-factors, FI degrades C3b, which inhibits further complement activation. Genetic mutations in FI are associated with pathological conditions like age-related macular degeneration and atypical hemolytic uremic syndome. Here, we evaluated eight recombinant FI genetic variants found in patients. We assessed FI's co-factor activity in the presence of two co-factors; Factor H and soluble CR1. Different analytical assays were employed; SDS-PAGE to evaluate the degradation of C3b, ELISA to measure the generation of fluid phase iC3b and the degradation of surface-bound C3b using a novel Luminex bead-based assay. We demonstrate that mutations in the FIMAC and SP domains of FI led to significantly reduced protease activity, whereas the two analyzed mutations in the LDLRA2 domain did not result in any profound changes in FI's function. The different assays employed displayed a strong positive correlation, but differences in the activity of the genetic variants Ile55Phe and Gly261Asp could only be observed by combining different methods and co-factors for evaluating FI activity. In conclusion, our results provide a new perspective regarding available diagnostic tools for assessing the impact of mutations in FI.
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Affiliation(s)
- Alexandra Gerogianni
- Linnaeus Centre for Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
- Department of Chemistry and Biomedicine, Linnaeus University, Kalmar, Sweden
| | - Laura M. Baas
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children’s Hospital, Nijmegen, Netherlands
| | - Dick J. Sjöström
- Linnaeus Centre for Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
- Department of Chemistry and Biomedicine, Linnaeus University, Kalmar, Sweden
| | - Nicole C. A. J. van de Kar
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children’s Hospital, Nijmegen, Netherlands
| | - Marit Pullen
- Department of Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Siem J. van de Peppel
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children’s Hospital, Nijmegen, Netherlands
| | - Per H. Nilsson
- Linnaeus Centre for Biomaterials Chemistry, Linnaeus University, Kalmar, Sweden
- Department of Chemistry and Biomedicine, Linnaeus University, Kalmar, Sweden
| | - Lambertus P. van den Heuvel
- Department of Pediatric Nephrology, Radboud University Medical Center, Amalia Children’s Hospital, Nijmegen, Netherlands
- Department of Genetics, Radboud University Medical Center, Nijmegen, 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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3
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Hallam TM, Sharp SJ, Andreadi A, Kavanagh D. Complement factor I: Regulatory nexus, driver of immunopathology, and therapeutic. Immunobiology 2023; 228:152410. [PMID: 37478687 DOI: 10.1016/j.imbio.2023.152410] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/23/2023] [Accepted: 06/01/2023] [Indexed: 07/23/2023]
Abstract
Complement factor I (FI) is the nexus for classical, lectin and alternative pathway complement regulation. FI is an 88 kDa plasma protein that circulates in an inactive configuration until it forms a trimolecular complex with its cofactor and substrate whereupon a structural reorganization allows the catalytic triad to cleave its substrates, C3b and C4b. In keeping with its role as the master complement regulatory enzyme, deficiency has been linked to immunopathology. In the setting of complete FI deficiency, a consumptive C3 deficiency results in recurrent infections with encapsulated microorganisms. Aseptic cerebral inflammation and vasculitic presentations are also less commonly observed. Heterozygous mutations in the factor I gene (CFI) have been demonstrated to be enriched in atypical haemolytic uraemic syndrome, albeit with a very low penetrance. Haploinsufficiency of CFI has also been associated with decreased retinal thickness and is a strong risk factor for the development of age-related macular degeneration. Supplementation of FI using plasma purified or recombinant protein has long been postulated, however, technical difficulties prevented progression into clinical trials. It is only using gene therapy that CFI supplementation has reached the clinic with GT005 in phase I/II clinical trials for geographic atrophy.
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Affiliation(s)
- T M Hallam
- Gyroscope Therapeutics Limited, A Novartis Company, Rolling Stock Yard, London N7 9AS, UK; Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne NE1 7RU, UK; National Renal Complement Therapeutics Centre, Building 26, Royal Victoria Infirmary, UK
| | - S J Sharp
- Gyroscope Therapeutics Limited, A Novartis Company, Rolling Stock Yard, London N7 9AS, UK
| | - A Andreadi
- Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne NE1 7RU, UK; National Renal Complement Therapeutics Centre, Building 26, Royal Victoria Infirmary, UK
| | - D Kavanagh
- Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne NE1 7RU, UK; National Renal Complement Therapeutics Centre, Building 26, Royal Victoria Infirmary, UK; NIHR Newcastle Biomedical Research Centre, Biomedical Research Building, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK.
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4
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Khandelwal P, Joshi A, Mathur A, Puraswani M, Gurjar BS, Sinha A, Hari P, Faruq M, Bagga A. Variants in complement genes are uncommon in patients with anti-factor H autoantibody-associated atypical hemolytic uremic syndrome. Pediatr Nephrol 2023; 38:2659-2668. [PMID: 36622444 DOI: 10.1007/s00467-022-05862-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/13/2022] [Accepted: 12/13/2022] [Indexed: 01/10/2023]
Abstract
BACKGROUND Coexisting genetic variants in patients with anti-factor H (FH)-associated atypical hemolytic uremic syndrome (aHUS) have implications for therapy. We estimated the prevalence of complement genetic variants in children with anti-FH aHUS from a prospective nationwide cohort and determined if significant genetic variants impact long-term kidney outcomes. METHODS Of 436 patients in the database, 77 consecutive patients, 21 with a relapse and 9 with kidney failure and/or death were included. Targeted sequencing, using a 27-gene panel including CFH, CFI, CFB, C3, CD46, PLG, DGKE, and THBD and multiplex ligation-dependent probe amplification of CFH-CFHR region, was performed. The adverse outcome was eGFR < 30 ml/min/1.73 m2 or death. RESULTS Patients had high anti-FH titers 5670 (2177-13,545) AU/ml, relapsing course (42.1%), and adverse outcomes (19.6%). Variants, chiefly of unknown significance, were found in 7 (6.5%; 95% CI 3.1-13.2%); a pathogenic variant was found in one patient. Homozygous deletion of CFHR1 was present in 91.6% compared to 9.8% in 184 healthy controls. Plasma exchanges and immunosuppression showed a trend of improving outcomes, independent of genetic defects (HR 0.32; P = 0.070). Meta-analysis of 18 studies (384 patients) showed that the pooled prevalence of pathogenic and likely pathogenic variants was 3% (95% CI 0-8%). Of 37 total variants in the meta-analysis, 7 (18.9%) each were pathogenic and likely pathogenic; others were variants of unknown significance. CONCLUSIONS Significant variants in complement regulatory genes are rare in patients with anti-FH-associated aHUS. Irrespective of genetic defects, plasma exchanges and immunosuppression showed a statistical trend to improved outcomes. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Priyanka Khandelwal
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Aditi Joshi
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Aradhana Mathur
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Mamta Puraswani
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Bahadur Singh Gurjar
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Mohammed Faruq
- Genomics and Molecular Medicine, CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, ICMR Center for Advanced Research in Nephrology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
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5
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Hallam TM, Cox TE, Smith-Jackson K, Brocklebank V, Baral AJ, Tzoumas N, Steel DH, Wong EKS, Shuttleworth VG, Lotery AJ, Harris CL, Marchbank KJ, Kavanagh D. A novel method for real-time analysis of the complement C3b:FH:FI complex reveals dominant negative CFI variants in age-related macular degeneration. Front Immunol 2022; 13:1028760. [PMID: 36643920 PMCID: PMC9832388 DOI: 10.3389/fimmu.2022.1028760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 11/14/2022] [Indexed: 12/29/2022] Open
Abstract
Age-related macular degeneration (AMD) is linked to 2 main disparate genetic pathways: a chromosome 10 risk locus and the alternative pathway (AP) of complement. Rare genetic variants in complement factor H (CFH; FH) and factor I (CFI; FI) are associated with AMD. FH acts as a soluble cofactor to facilitate FI's cleavage and inactivation of the central molecule of the AP, C3b. For personalised treatment, sensitive assays are required to define the functional significance of individual AP genetic variants. Generation of recombinant FI for functional analysis has thus far been constrained by incomplete processing resulting in a preparation of active and inactive protein. Using an internal ribosomal entry site (IRES)-Furin-CFI expression vector, fully processed FI was generated with activity equivalent to serum purified FI. By generating FI with an inactivated serine protease domain (S525A FI), a real-time surface plasmon resonance assay of C3b:FH:FI complex formation for characterising variants in CFH and CFI was developed and correlated well with standard assays. Using these methods, we further demonstrate that patient-associated rare genetic variants lacking enzymatic activity (e.g. CFI I340T) may competitively inhibit the wild-type FI protein. The dominant negative effect identified in inactive factor I variants could impact on the pharmacological replacement of FI currently being investigated for the treatment of dry AMD.
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Affiliation(s)
- Thomas M. Hallam
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Thomas E. Cox
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Kate Smith-Jackson
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Vicky Brocklebank
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - April J. Baral
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Nikolaos Tzoumas
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - David H. Steel
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,Sunderland Eye Infirmary, Sunderland, United Kingdom,Biosciences Institute, Newcastle University, International Centre for Life, Newcastle upon Tyne, United Kingdom
| | - Edwin K. S. Wong
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Victoria G. Shuttleworth
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Andrew J. Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, Southampton General Hospital, University of Southampton, Southampton, United Kingdom
| | - Claire L. Harris
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Kevin J. Marchbank
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - David Kavanagh
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom,National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom,National Institute for Health and Care Research (NIHR) Newcastle Biomedical Research Centre, Biomedical Research Building, Newcastle upon Tyne, United Kingdom,*Correspondence: David Kavanagh,
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6
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de Jong S, de Breuk A, Bakker B, Katti S, Hoyng CB, Nilsson SC, Blom AM, van den Heuvel LP, den Hollander AI, Volokhina EB. Functional Analysis of Variants in Complement Factor I Identified in Age-Related Macular Degeneration and Atypical Hemolytic Uremic Syndrome. Front Immunol 2022; 12:789897. [PMID: 35069568 PMCID: PMC8766660 DOI: 10.3389/fimmu.2021.789897] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/13/2021] [Indexed: 11/23/2022] Open
Abstract
Complement factor I (FI) is a central inhibitor of the complement system, and impaired FI function increases complement activation, contributing to diseases such as age-related macular degeneration (AMD) and atypical hemolytic uremic syndrome (aHUS). Genetic variation in complement factor I (CFI) has been identified in both AMD and aHUS, with more than half of these variants leading to reduced FI secretion levels. For many of the variants with normal FI secretion, however, functional implications are not yet known. Here we studied 11 rare missense variants, with FI secretion levels comparable to wildtype, but a predicted damaging effects based on the Combined Annotation Dependent Depletion (CADD) score. Three variants (p.Pro50Ala, p.Arg339Gln, and p.Ser570Thr) were analyzed in plasma and serum samples of carriers affected by AMD. All 11 variants (nine for the first time in this study) were recombinantly expressed and the ability to degrade C3b was studied with the C3b degradation assay. The amount of degradation was determined by measuring the degradation product iC3b with ELISA. Eight of 11 (73%) mutant proteins (p.Pro50Ala, p.Arg339Gln, p.Ile340Thr, p.Gly342Glu, p.Gly349Arg, p.Arg474Gln, p.Gly487Cys, and p.Gly512Ser) showed significantly impaired C3b degradation, and were therefore classified as likely pathogenic. Our data indicate that genetic variants in CFI with a CADD score >20 are likely to affect FI function, and that monitoring iC3b in a degradation assay is a useful tool to establish the pathogenicity of CFI variants in functional studies.
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Affiliation(s)
- Sarah de Jong
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Anita de Breuk
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Bjorn Bakker
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Suresh Katti
- Gemini Therapeutics Inc., Cambridge, MA, United States
| | - Carel B Hoyng
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands
| | - Sara C Nilsson
- Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Anna M Blom
- Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Lambert P van den Heuvel
- Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
| | - Anneke I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Elena B Volokhina
- Amalia Children's Hospital, Radboud University Medical Center, Nijmegen, Netherlands.,Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, Netherlands
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7
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de Jong S, Volokhina EB, de Breuk A, Nilsson SC, de Jong EK, van der Kar NCAJ, Bakker B, Hoyng CB, van den Heuvel LP, Blom AM, den Hollander AI. Effect of rare coding variants in the CFI gene on Factor I expression levels. Hum Mol Genet 2021; 29:2313-2324. [PMID: 32510551 PMCID: PMC7424754 DOI: 10.1093/hmg/ddaa114] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/29/2020] [Accepted: 06/03/2020] [Indexed: 12/25/2022] Open
Abstract
Factor I (FI) is one of the main inhibitors of complement activity, and numerous rare coding variants have been reported in patients with age-related macular degeneration, atypical hemolytic uremic syndrome and C3 glomerulopathy. Since many of these variants are of unknown clinical significance, this study aimed to determine the effect of rare coding variants in the complement factor I (CFI) gene on FI expression. We measured FI levels in plasma samples of carriers of rare coding variants and in vitro in the supernatants of epithelial cells expressing recombinant FI. FI levels were measured in 177 plasma samples of 155 individuals, carrying 24 different rare coding variants in CFI. In carriers of the variants p.Gly119Arg, p.Leu131Arg, p.Gly188Ala and c.772G>A (r.685_773del), significantly reduced FI plasma levels were detected. Furthermore, recombinant FI expression levels were determined for 126 rare coding variants. Of these variants 68 (54%) resulted in significantly reduced FI expression in supernatant compared to wildtype (WT). The recombinant protein expression levels correlated significantly with the FI level in plasma of carriers of CFI variants. In this study, we performed the most comprehensive FI expression level analysis of rare coding variants in CFI to date. More than half of CFI variants lead to reduced FI expression, which might impair complement regulation in vivo. Our study will aid the interpretation of rare coding CFI variants identified in clinical practice, which is in particular important in light of patient inclusion in ongoing clinical trials for CFI gene supplementation in AMD.
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Affiliation(s)
- Sarah de Jong
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Elena B Volokhina
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.,Amalia Children's Hospital, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Anita de Breuk
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Sara C Nilsson
- Department of Translational Medicine, Lund University, 21428 Malmö, Sweden
| | - Eiko K de Jong
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Nicole C A J van der Kar
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.,Amalia Children's Hospital, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Bjorn Bakker
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Lambert P van den Heuvel
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands.,Department of Laboratory Medicine, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Anna M Blom
- Department of Translational Medicine, Lund University, 21428 Malmö, Sweden
| | - Anneke I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
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8
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Kar S, Krishnamurthy S, Karunakar P, Maya M, Thangaraj A, Agarwal Y. A rare cause of recurrent acute kidney injury in a 3-year-old girl: Answers. Pediatr Nephrol 2021; 36:2033-2037. [PMID: 33427983 DOI: 10.1007/s00467-020-04885-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 11/27/2020] [Indexed: 11/27/2022]
Affiliation(s)
- Shrutiprajna Kar
- Department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, 605006, India
| | - Sriram Krishnamurthy
- Department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, 605006, India.
| | - Pediredla Karunakar
- Department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, 605006, India
| | - Malini Maya
- Department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, 605006, India
| | - Abarna Thangaraj
- Department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, 605006, India
| | - Yamini Agarwal
- Department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Pondicherry, 605006, India
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9
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Khan AH, Sutton J, Cree AJ, Khandhadia S, De Salvo G, Tobin J, Prakash P, Arora R, Amoaku W, Charbel Issa P, MacLaren RE, Bishop PN, Peto T, Mohamed Q, Steel DH, Sivaprasad S, Bailey C, Menon G, Kavanagh D, Lotery AJ. Prevalence and phenotype associations of complement factor I mutations in geographic atrophy. Hum Mutat 2021; 42:1139-1152. [PMID: 34153144 PMCID: PMC9290714 DOI: 10.1002/humu.24242] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/09/2021] [Accepted: 06/13/2021] [Indexed: 12/20/2022]
Abstract
Rare variants in the complement factor I (CFI) gene, associated with low serum factor I (FI) levels, are strong risk factors for developing the advanced stages of age-related macular degeneration (AMD). No studies have been undertaken on the prevalence of disease-causing CFI mutations in patients with geographic atrophy (GA) secondary to AMD. A multicenter, cross-sectional, noninterventional study was undertaken to identify the prevalence of pathogenic rare CFI gene variants in an unselected cohort of patients with GA and low FI levels. A genotype-phenotype study was performed. Four hundred and sixty-eight patients with GA secondary to AMD were recruited to the study, and 19.4% (n = 91) demonstrated a low serum FI concentration (below 15.6 μg/ml). CFI gene sequencing on these patients resulted in the detection of rare CFI variants in 4.7% (n = 22) of recruited patients. The prevalence of CFI variants in patients with low serum FI levels and GA was 25%. Of the total patients recruited, 3.2% (n = 15) expressed a CFI variant classified as pathogenic or likely pathogenic. The presence of reticular pseudodrusen was detected in all patients with pathogenic CFI gene variants. Patients with pathogenic CFI gene variants and low serum FI levels might be suitable for FI supplementation in therapeutic trials.
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Affiliation(s)
- Adnan H Khan
- Division of Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Janice Sutton
- Division of Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Angela J Cree
- Division of Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Samir Khandhadia
- Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Gabriella De Salvo
- Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - John Tobin
- Gyroscope Therapeutics Limited, Stevenage, UK
| | - Priya Prakash
- The Eye Unit, The Princess Alexandra Hospital NHS Trust, Harlow, UK
| | - Rashi Arora
- Department of Ophthalmology, Salisbury District Hospital, Salisbury NHS Foundation Trust, Salisbury, UK
| | - Winfried Amoaku
- Eye and ENT Centre, Queen's Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Peter Charbel Issa
- Oxford Eye Hospital and Oxford NIHR Biomedical Research Centre, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.,Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Robert E MacLaren
- Oxford Eye Hospital and Oxford NIHR Biomedical Research Centre, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.,Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Paul N Bishop
- Division of Evolution and Genomic Sciences, Faculty of Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, UK.,Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - Tunde Peto
- Centre for Public Health, School of Medicine, Institute of Clinical Sciences, Queen's University Belfast, Belfast, UK
| | - Quresh Mohamed
- Department of Ophthalmology, Gloucestershire Royal Hospital, Gloucestershire Hospitals NHS Foundation Trust, Gloucester, UK
| | - David H Steel
- Sunderland Eye Infirmary, South Tyneside and Sunderland NHS Foundation Trust, Sunderland, UK.,Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Sobha Sivaprasad
- Institute of Ophthalmology, University College London, London, UK
| | - Clare Bailey
- Clinical Research Unit, Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Geeta Menon
- Department of Ophthalmology, Frimley Park Hospital, Frimley Health NHS Foundation Trust, Camberley, UK
| | - David Kavanagh
- National Renal Complement Therapeutics Centre, Royal Victoria Infirmary, Newcastle upon Tyne, UK.,Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Andrew J Lotery
- Division of Clinical Neurosciences, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
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10
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de Jong S, Gagliardi G, Garanto A, de Breuk A, Lechanteur YTE, Katti S, van den Heuvel LP, Volokhina EB, den Hollander AI. Implications of genetic variation in the complement system in age-related macular degeneration. Prog Retin Eye Res 2021; 84:100952. [PMID: 33610747 DOI: 10.1016/j.preteyeres.2021.100952] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/08/2021] [Accepted: 02/11/2021] [Indexed: 12/23/2022]
Abstract
Age-related macular degeneration (AMD) is the main cause of vision loss among the elderly in the Western world. While AMD is a multifactorial disease, the complement system was identified as one of the main pathways contributing to disease risk. The strong link between the complement system and AMD was demonstrated by genetic associations, and by elevated complement activation in local eye tissue and in the systemic circulation of AMD patients. Several complement inhibitors have been and are being explored in clinical trials, but thus far with limited success, leaving the majority of AMD patients without treatment options to date. This indicates that there is still a gap of knowledge regarding the functional implications of the complement system in AMD pathogenesis and how to bring these towards clinical translation. Many different experimental set-ups and disease models have been used to study complement activation in vivo and in vitro, and recently emerging patient-derived induced pluripotent stem cells and genome-editing techniques open new opportunities to study AMD disease mechanisms and test new therapeutic strategies in the future. In this review we provide an extensive overview of methods employed to understand the molecular processes of complement activation in AMD pathogenesis. We discuss the findings, advantages and challenges of each approach and conclude with an outlook on how recent, exciting developments can fill in current knowledge gaps and can aid in the development of effective complement-targeting therapeutic strategies in AMD.
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Affiliation(s)
- Sarah de Jong
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Giuliana Gagliardi
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Alejandro Garanto
- Department of Human Genetics, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Pediatrics, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Amalia Children's Hospital, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Anita de Breuk
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Yara T E Lechanteur
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Suresh Katti
- Gemini Therapeutics Inc., Cambridge, MA, 02139, USA
| | - Lambert P van den Heuvel
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Amalia Children's Hospital, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Laboratory Medicine, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Elena B Volokhina
- Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Amalia Children's Hospital, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Laboratory Medicine, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands
| | - Anneke I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands; Department of Human Genetics, Radboud University Medical Center, 6525, GA, Nijmegen, the Netherlands.
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11
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Cai X, Qiu W, Qian M, Feng S, Peng C, Zhang J, Wang Y, Wang Y. A Candidate Prognostic Biomarker Complement Factor I Promotes Malignant Progression in Glioma. Front Cell Dev Biol 2021; 8:615970. [PMID: 33614625 PMCID: PMC7889977 DOI: 10.3389/fcell.2020.615970] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 12/21/2020] [Indexed: 11/20/2022] Open
Abstract
Objectives: Glioma is the most common and aggressive type of primary central nervous system (CNS) tumor in adults and is associated with substantial mortality rates. The aim of our study was to evaluate the prognostic significance and function of the complement factor I (CFI) in glioma. Materials and Methods: The expression levels of CFI in glioma tissues and the survival of the CFIhigh and CFIlow patient groups were analyzed using The Cancer Genome Atlas (TCGA) database and Genotype-Tissue Expression (GTEx). The correlation between CFI expression and clinicopathological features of glioma was determined by univariate and multivariate Cox regression analyses in the Chinese Glioma Genome Atlas (CGGA) database. The functional role of CFI in glioma was established through routine in vitro and in vivo assays. Results: CFI is overexpressed in glioma and its high levels correlated with poor outcomes in both TCGA and CGGA datasets. Furthermore, CFI was identified as an independent prognostic factor of glioma in the CGGA database. CFI knockdown in glioma cell lines inhibited growth in vitro and in vivo, whereas its ectopic expression increased glioma cell proliferation, migration, and invasion in vitro. CFI protein levels were also significantly higher in the glioma tissues resected from patients and correlated to worse prognosis. Conclusions: CFI is a potential prognostic biomarker in glioma and drives malignant progression.
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Affiliation(s)
- Xiaomin Cai
- Department of Neurosurgery, The 904th Hospital of Joint Logistic Support Force of People's Liberation Army (PLA), Clinical Medical College of Anhui Medical University, Wuxi, China
| | - Wenjin Qiu
- Department of Neurosurgery, The Affiliated Hospital of Guizhou Medical University, Guiyang, China
| | - Mengshu Qian
- Department of Emergency, The 904th Hospital of Joint Logistic Support Force of People's Liberation Army (PLA), Clinical Medical College of Anhui Medical University, Wuxi, China
| | - Shuang Feng
- Department of Encephalopathy, The Third Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China
| | - Chenghao Peng
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong, University of Science and Technology, Wuhan, China
| | - Jiale Zhang
- Department of Neurosurgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Yi Wang
- Department of Urology, Affiliated Hospital of Nantong University, Nantong, China
| | - Yuhai Wang
- Department of Neurosurgery, The 904th Hospital of Joint Logistic Support Force of People's Liberation Army (PLA), Clinical Medical College of Anhui Medical University, Wuxi, China
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12
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Timmermans SAMEG, Damoiseaux JGMC, Werion A, Reutelingsperger CP, Morelle J, van Paassen P. Functional and Genetic Landscape of Complement Dysregulation Along the Spectrum of Thrombotic Microangiopathy and its Potential Implications on Clinical Outcomes. Kidney Int Rep 2021; 6:1099-1109. [PMID: 33912760 PMCID: PMC8071658 DOI: 10.1016/j.ekir.2021.01.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Accepted: 01/25/2021] [Indexed: 01/30/2023] Open
Abstract
Introduction The syndromes of thrombotic microangiopathy (TMA) are diverse and represent severe endothelial damage caused by various mechanisms. The complement system plays a major role in a subset of patients with TMA, and its recognition is of clinical importance because it guides choice and duration of treatment. Methods We studied a well-defined cohort of patients with TMA and hypothesized that assessment of serum-induced ex vivo C5b9 formation on the endothelium and screening for rare variants in complement genes can better categorize TMA. Results Massive ex vivo C5b9 formation was found in all patients with primary atypical hemolytic uremic syndrome (n/N = 11/11) and in 59% of patients with TMA and coexisting conditions (n/N = 30/51). Massive ex vivo C5b9 formation was associated with rare genetic variants (45% [n/N = 20/44] vs. 0% [n/N = 0/21] patients with normal ex vivo C5b9 formation; P < 0.001). Massive ex vivo C5b9 formation was associated with favorable renal response to therapeutic complement inhibition in patients with TMA and coexisting conditions (86% [n/N = 12/14] vs. 31% [n/N = 5/16] of untreated patients; P < 0.001), indicating complement-mediated TMA rather than secondary disease. Among treated patients, the odds ratio for 1-year kidney survival was 12.0 (95% confidence interval 1.2-115.4). TMA recurrence was linked to rare genetic variants in all cases. Patients with normal ex vivo C5b9 formation had an acute, nonrelapsing form of TMA. Conclusions Ex vivo C5b9 formation and genetic testing appears to categorize TMAs into different groups because it identifies complement as a driving factor of disease, with potential therapeutic and prognostic implications.
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Affiliation(s)
- Sjoerd A M E G Timmermans
- Department of Nephrology and Clinical Immunology.,Department of Biochemistry, Cardiovascular Research Institute, Maastricht, The Netherlands
| | - Jan G M C Damoiseaux
- Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Alexis Werion
- Division of Nephrology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | | | - Johann Morelle
- Division of Nephrology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.,Institut de Recherche Experimentale et Clinique, UCLouvain, Brussels, Belgium
| | - Pieter van Paassen
- Department of Nephrology and Clinical Immunology.,Department of Biochemistry, Cardiovascular Research Institute, Maastricht, The Netherlands
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13
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Java A, Baciu P, Widjajahakim R, Sung YJ, Yang J, Kavanagh D, Atkinson J, Seddon J. Functional Analysis of Rare Genetic Variants in Complement Factor I ( CFI) using a Serum-Based Assay in Advanced Age-related Macular Degeneration. Transl Vis Sci Technol 2020; 9:37. [PMID: 32908800 PMCID: PMC7453046 DOI: 10.1167/tvst.9.9.37] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/26/2020] [Indexed: 11/24/2022] Open
Abstract
Purpose Factor I (FI) is a serine protease regulator of the complement system. Genetic variants in CFI are associated with advanced age-related macular degeneration (AAMD). However, the clinical and functional impact of these variants is unknown. This study assessed the functional significance of rare CFI variants using a serum-based assay. Methods Carriers of rare variants with (n = 78) and without AAMD (n = 28), and noncarriers with (n = 49) and without AMD (n = 44) were evaluated. Function of FI was determined by measuring the proteolytic cleavage of C3b to iC3b, using the cofactor protein, Factor H. Results CFI variants were categorized into three groups based on antigenic and functional assessments. Type 1 variants (n = 18) in 35 patients with AAMD demonstrated low serum FI levels and a corresponding decrease in FI function. Type 2 variants (n = 6) in 7 individuals demonstrated normal serum FI antigenic levels but reduced degradation of C3b to iC3b. Type 3 variants (n = 15) in 64 individuals demonstrated normal antigenic levels and degradation of C3b to iC3b. However, iC3b generation was low when measured per unit of FI. Thus most rare CFI variants demonstrate either low antigenic levels (type 1) or normal levels but reduced function (types 2 or 3). Conclusions Results provide for the first time a comprehensive functional assessment in serum of CFI rare genetic variants and further establish FI's key role in the pathogenesis of AAMD. Translational Relevance Stratifying patients in the clinic with a rare CFI variant will facilitate screening and targeting patients most likely to benefit from complement therapies.
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Affiliation(s)
- Anuja Java
- Divisions of Nephrology and Rheumatology, Department of Medicine, Washington University, St. Louis, MO, USA
| | | | - Rafael Widjajahakim
- Department of Ophthalmology and Visual Sciences, University of Massachusetts School of Medicine, Worcester, MA, USA
| | - Yun Ju Sung
- Department of Psychiatry and Division of Biostatistics Washington University School of Medicine in St. Louis, MO, USA
| | | | - David Kavanagh
- National Renal Complement Therapeutics Centre, Newcastle University, Newcastle upon Tyne, UK
| | - John Atkinson
- Divisions of Nephrology and Rheumatology, Department of Medicine, Washington University, St. Louis, MO, USA
| | - Johanna Seddon
- Department of Ophthalmology and Visual Sciences, University of Massachusetts School of Medicine, Worcester, MA, USA
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14
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Fayek SA, Allam SR, Martinez E, Pan G, Dao A, Rofaiel G. Atypical Hemolytic Uremic Syndrome After Kidney Transplantation: Lessons Learned From the Good, the Bad, and the Ugly. A Case Series With Literature Review. Transplant Proc 2020; 52:146-152. [PMID: 31924403 DOI: 10.1016/j.transproceed.2019.10.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 10/06/2019] [Indexed: 11/30/2022]
Abstract
Atypical hemolytic uremic syndrome (aHUS) after kidney transplantation is rare and carries a grave outcome. We present a single-center experience of all aHUS cases since the program's inception. Six patients were diagnosed with aHUS, all after kidney transplants, except for 1 patient. All had nonreactive crossmatches. Delayed graft function (DGF) occurred in 2 patients. Five patients developed aHUS after transplant; 4 (80%) of these patients manifested aHUS ≤ 14 days. All were confirmed by allograft biopsy. Genetic testing was abnormal in all patients except for 1 patient. Actual patient and graft survival during the first year was 100% and 83.3%, respectively. A single graft was lost early in the study secondary to aHUS (eculizumab was not used in the treatment process). Prophylactic and therapeutic use of eculizumab salvaged all other cases. At 1 year, mean creatinine level was 1.9 mg/dL (range, 1.3-2.5). After 6 months of eculizumab treatment (halted in 2 cases) 1 patient had recurrence 2 months later and eculizumab was restarted. However, graft function continued to worsen, and the graft was ultimately lost at 20 months after kidney transplantation. High index of suspicion, prompt diagnosis, and utilization of eculizumab are key to successful salvage of allografts in cases of aHUS after kidney transplantation. aHUS can be prevented by prophylactic use of eculizumab. It still needs to be determined when and if eculizumab therapy can be safely discontinued.
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Affiliation(s)
- Sameh A Fayek
- Department of Surgery, Section of Abdominal Transplantation, Inova Fairfax Medical Campus, Falls Church, VA, Unites States; Department of Surgery, Faculty of Medicine, Cairo University, Egypt.
| | - Sridhar R Allam
- Department of Transplantation, Medical City Fort Worth, Fort Worth, Texas, United States
| | - Eryberto Martinez
- Department of Surgery, Division of Transplantation and Advanced Hepatobiliary Surgery, University of Utah, Salt Lake City, Utah, United States
| | - Gilbert Pan
- Department of Surgery, Division of Transplantation and Advanced Hepatobiliary Surgery, University of Utah, Salt Lake City, Utah, United States
| | - Ann Dao
- Department of Transplantation, Medical City Fort Worth, Fort Worth, Texas, United States
| | - George Rofaiel
- Department of Surgery, Division of Transplantation and Advanced Hepatobiliary Surgery, University of Utah, Salt Lake City, Utah, United States
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15
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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] [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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16
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Valoti E, Alberti M, Iatropoulos P, Piras R, Mele C, Breno M, Cremaschi A, Bresin E, Donadelli R, Alizzi S, Amoroso A, Benigni A, Remuzzi G, Noris M. Rare Functional Variants in Complement Genes and Anti-FH Autoantibodies-Associated aHUS. Front Immunol 2019; 10:853. [PMID: 31118930 PMCID: PMC6504697 DOI: 10.3389/fimmu.2019.00853] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/02/2019] [Indexed: 01/06/2023] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare disease characterized by microangiopathic hemolytic anemia, thrombocytopenia and renal failure. It is caused by genetic or acquired defects of the complement alternative pathway. Factor H autoantibodies (anti-FHs) have been reported in 10% of aHUS patients and are associated with the deficiency of factor H-related 1 (FHR1). However, FHR1 deficiency is not enough to cause aHUS, since it is also present in about 5% of Caucasian healthy subjects. In this study we evaluated the prevalence of genetic variants in CFH, CD46, CFI, CFB, C3, and THBD in aHUS patients with anti-FHs, using healthy subjects with FHR1 deficiency, here defined “supercontrols,” as a reference group. “Supercontrols” are more informative than general population because they share at least one risk factor (FHR1 deficiency) with aHUS patients. We analyzed anti-FHs in 305 patients and 30 were positive. The large majority were children (median age: 7.7 [IQR, 6.6–9.9] years) and 83% lacked FHR1 (n = 25, cases) due to the homozygous CFHR3-CFHR1 deletion (n = 20), or the compound heterozygous CFHR3-CFHR1 and CFHR1-CFHR4 deletions (n = 4), or the heterozygous CFHR3-CFHR1 deletion combined with a frameshift mutation in CFHR1 that generates a premature stop codon (n = 1). Of the 960 healthy adult subjects 48 had the FHR1 deficiency (“supercontrols”). Rare likely pathogenetic variants in CFH, THBD, and C3 were found in 24% of cases (n = 6) compared to 2.1% of the “supercontrols” (P-value = 0.005). We also found that the CFH H3 and the CD46GGAAC haplotypes are not associated with anti-FHs aHUS, whereas these haplotypes are enriched in aHUS patients without anti-FHs, which highlights the differences in the genetic basis of the two forms of the disease. Finally, we confirm that common infections are environmental factors that contribute to the development of anti-FHs aHUS in genetically predisposed individuals, which fits with the sharp peak of incidence during scholar-age. Further studies are needed to fully elucidate the complex genetic and environmental factors underlying anti-FHs aHUS and to establish whether the combination of anti-FHs with likely pathogenetic variants or other risk factors influences disease outcome and response to therapies.
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Affiliation(s)
- Elisabetta Valoti
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Marta Alberti
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Paraskevas Iatropoulos
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Rossella Piras
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Caterina Mele
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Matteo Breno
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Alessandra Cremaschi
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Elena Bresin
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Roberta Donadelli
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Silvia Alizzi
- Azienda Ospedaliera-Universitaria, Città della Salute e della Scienza and Department of Medical Sciences, University of Turin, Turin, Italy
| | - Antonio Amoroso
- Azienda Ospedaliera-Universitaria, Città della Salute e della Scienza and Department of Medical Sciences, University of Turin, Turin, Italy
| | - Ariela Benigni
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Giuseppe Remuzzi
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy.,'L. Sacco' Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Marina Noris
- Clinical Research Center for Rare Diseases 'Aldo e Cele Daccò', Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
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17
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Yoshida Y, Kato H, Ikeda Y, Nangaku M. Pathogenesis of Atypical Hemolytic Uremic Syndrome. J Atheroscler Thromb 2018; 26:99-110. [PMID: 30393246 PMCID: PMC6365154 DOI: 10.5551/jat.rv17026] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a type of thrombotic microangiopathy (TMA) defined by thrombocytopenia, microangiopathic hemolytic anemia, and renal failure. aHUS is caused by uncontrolled complement activation in the alternative pathway (AP). A variety of genetic defects in complement-related factors or acquired autoantibodies to the complement regulators have been found in 50 to 60% of all cases. Recently, however, the classification and diagnosis of aHUS are becoming more complicated. One reason for this is that some factors, which have not been regarded as complement-related factors, have been reported as predisposing factors for phenotypic aHUS. Given that genotype is highly correlated with the phenotype of aHUS, careful analysis of underlying genetic abnormalities or acquired factors is needed to predict the prognosis or to decide an optimal treatment for the disease. Another reason is that complement dysregulation in the AP have also been found in a part of other types of TMA such as transplantation-related TMA and pregnancy-related complication. Based on these findings, it is now time to redefine aHUS according to the genetic or acquired background of abnormalities.Here, we review the pathogeneses and the corresponding phenotypes of aHUS and complement-related TMAs.
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Affiliation(s)
- Yoko Yoshida
- Division of Nephrology and Endocrinology, the University of Tokyo Hospital
| | - Hideki Kato
- Department of Prevention of Diabetes and Lifestyle-Related Diseases Graduate School of Medicine, the University of Tokyo
| | - Yoichiro Ikeda
- Division of Nephrology and Endocrinology, the University of Tokyo Hospital
| | - Masaomi Nangaku
- Division of Nephrology and Endocrinology, the University of Tokyo Hospital
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18
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Nanthapisal S, Eleftheriou D, Gilmour K, Leone V, Ramnath R, Omoyinmi E, Hong Y, Klein N, Brogan PA. Cutaneous Vasculitis and Recurrent Infection Caused by Deficiency in Complement Factor I. Front Immunol 2018; 9:735. [PMID: 29696024 PMCID: PMC5904195 DOI: 10.3389/fimmu.2018.00735] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 03/26/2018] [Indexed: 11/23/2022] Open
Abstract
Cutaneous leukocytoclastic vasculitis arises from immune complex deposition and dysregulated complement activation in small blood vessels. There are many causes, including dysregulated host response to infection, drug reactions, and various autoimmune conditions. It is increasingly recognised that some monogenic autoinflammatory diseases cause vasculitis, although genetic causes of vasculitis are extremely rare. We describe a child of consanguineous parents who presented with chronic cutaneous leukocytoclastic vasculitis, recurrent upper respiratory tract infection, and hypocomplementaemia. A homozygous p.His380Arg mutation in the complement factor I (CFI) gene CFI was identified as the cause, resulting in complete absence of alternative complement pathway activity, decreased classical complement activity, and low levels of serum factor I, C3, and factor H. C4 and C2 levels were normal. The same homozygous mutation and immunological defects were also identified in an asymptomatic sibling. CFI deficiency is thus now added to the growing list of monogenic causes of vasculitis and should always be considered in vasculitis patients found to have persistently low levels of C3 with normal C4.
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Affiliation(s)
- Sira Nanthapisal
- Infection Inflammation and Rheumatology Section, Great Ormond Street Institute of Child Health, University College London, Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom.,Department of Pediatrics, Faculty of Medicine, Thammasat University, Pathumthani, Thailand
| | - Despina Eleftheriou
- Infection Inflammation and Rheumatology Section, Great Ormond Street Institute of Child Health, University College London, Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Kimberly Gilmour
- Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Valentina Leone
- Department of Paediatric Rheumatology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
| | - Radhika Ramnath
- Department of Histopathology, St. James University Hospital, Leeds, United Kingdom
| | - Ebun Omoyinmi
- Infection Inflammation and Rheumatology Section, Great Ormond Street Institute of Child Health, University College London, Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Ying Hong
- Infection Inflammation and Rheumatology Section, Great Ormond Street Institute of Child Health, University College London, Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Nigel Klein
- Infection Inflammation and Rheumatology Section, Great Ormond Street Institute of Child Health, University College London, Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Paul A Brogan
- Infection Inflammation and Rheumatology Section, Great Ormond Street Institute of Child Health, University College London, Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
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19
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Wong EKS, Kavanagh D. Diseases of complement dysregulation-an overview. Semin Immunopathol 2018; 40:49-64. [PMID: 29327071 PMCID: PMC5794843 DOI: 10.1007/s00281-017-0663-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/01/2017] [Indexed: 02/07/2023]
Abstract
Atypical hemolytic uremic syndrome (aHUS), C3 glomerulopathy (C3G), and paroxysmal nocturnal hemoglobinuria (PNH) are prototypical disorders of complement dysregulation. Although complement overactivation is common to all, cell surface alternative pathway dysregulation (aHUS), fluid phase alternative pathway dysregulation (C3G), or terminal pathway dysregulation (PNH) predominates resulting in the very different phenotypes seen in these diseases. The mechanism underlying the dysregulation also varies with predominant acquired autoimmune (C3G), somatic mutations (PNH), or inherited germline mutations (aHUS) predisposing to disease. Eculizumab has revolutionized the treatment of PNH and aHUS although has been less successful in C3G. With the next generation of complement therapeutic in late stage development, these archetypal complement diseases will provide the initial targets.
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Affiliation(s)
- Edwin K S Wong
- The National Renal Complement Therapeutics Centre, aHUS Service, Building 26, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, UK.,Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - David Kavanagh
- The National Renal Complement Therapeutics Centre, aHUS Service, Building 26, Royal Victoria Infirmary, Queen Victoria Road, Newcastle upon Tyne, NE1 4LP, UK. .,Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK.
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20
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Roumenina LT, Rayes J, Frimat M, Fremeaux-Bacchi V. Endothelial cells: source, barrier, and target of defensive mediators. Immunol Rev 2017; 274:307-329. [PMID: 27782324 DOI: 10.1111/imr.12479] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Endothelium is strategically located at the interface between blood and interstitial tissues, placing thus endothelial cell as a key player in vascular homeostasis. Endothelial cells are in a dynamic equilibrium with their environment and constitute concomitantly a source, a barrier, and a target of defensive mediators. This review will discuss the recent advances in our understanding of the complex crosstalk between the endothelium, the complement system and the hemostasis in health and in disease. The first part will provide a general introduction on endothelial cells heterogeneity and on the physiologic role of the complement and hemostatic systems. The second part will analyze the interplay between complement, hemostasis and endothelial cells in physiological conditions and their alterations in diseases. Particular focus will be made on the prototypes of thrombotic microangiopathic disorders, resulting from complement or hemostasis dysregulation-mediated endothelial damage: atypical hemolytic uremic syndrome and thrombotic thrombocytopenic purpura. Novel aspects of the pathophysiology of the thrombotic microangiopathies will be discussed.
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Affiliation(s)
- Lubka T Roumenina
- INSERM UMRS 1138, Cordeliers Research Center, Université Pierre et Marie Curie (UPMC-Paris-6) and Université Paris Descartes Sorbonne Paris-Cité, Paris, France.
| | - Julie Rayes
- Institute of Cardiovascular Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Marie Frimat
- INSERM UMR 995, Lille, France.,Nephrology Department, CHU Lille, Lille, France
| | - Veronique Fremeaux-Bacchi
- INSERM UMRS 1138, Cordeliers Research Center, Université Pierre et Marie Curie (UPMC-Paris-6) and Université Paris Descartes Sorbonne Paris-Cité, Paris, France.,Assistance Publique - Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital Européen Georges Pompidou, Paris, France
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21
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Abstract
The complement system is an essential part of the innate immune system that requires careful regulation to ensure responses are appropriately directed against harmful pathogens, while preventing collateral damage to normal host cells and tissues. While deficiency in some components of the complement pathway is associated with increased susceptibility to certain infections, it has also become clear that inappropriate activation of complement is an important contributor to human disease. A number of hematologic disorders are driven by complement, and these disorders may be termed "complementopathies". This includes paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), cold agglutinin disease (CAD) and other related disorders, which will be the focus of this review. A better understanding of the central role of the complement system in the pathophysiology of these disorders may allow for application of therapies directed at blocking the complement cascade.
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Affiliation(s)
- Andrea C Baines
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
| | - Robert A Brodsky
- Division of Hematology, Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
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22
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Abstract
Haemolytic uraemic syndrome (HUS) is defined by the simultaneous occurrence of nonimmune haemolytic anaemia, thrombocytopenia and acute renal failure. This leads to the pathological lesion termed thrombotic microangiopathy, which mainly affects the kidney, as well as other organs. HUS is associated with endothelial cell injury and platelet activation, although the underlying cause may differ. Most cases of HUS are associated with gastrointestinal infection with Shiga toxin-producing enterohaemorrhagic Escherichia coli (EHEC) strains. Atypical HUS (aHUS) is associated with complement dysregulation due to mutations or autoantibodies. In this review, we will describe the causes of HUS. In addition, we will review the clinical, pathological, haematological and biochemical features, epidemiology and pathogenetic mechanisms as well as the biochemical, microbiological, immunological and genetic investigations leading to diagnosis. Understanding the underlying mechanisms of the different subtypes of HUS enables tailoring of appropriate treatment and management. To date, there is no specific treatment for EHEC-associated HUS but patients benefit from supportive care, whereas patients with aHUS are effectively treated with anti-C5 antibody to prevent recurrences, both before and after renal transplantation.
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Affiliation(s)
- Diana Karpman
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Sebastian Loos
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Ramesh Tati
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Ida Arvidsson
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
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23
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Liszewski MK, Java A, Schramm EC, Atkinson JP. Complement Dysregulation and Disease: Insights from Contemporary Genetics. ANNUAL REVIEW OF PATHOLOGY 2017; 12:25-52. [PMID: 27959629 PMCID: PMC6020056 DOI: 10.1146/annurev-pathol-012615-044145] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The vertebrate complement system consists of sequentially interacting proteins that provide for a rapid and powerful host defense. Nearly 60 proteins comprise three activation pathways (classical, alternative, and lectin) and a terminal cytolytic pathway common to all. Attesting to its potency, nearly half of the system's components are engaged in its regulation. An emerging theme over the past decade is that variations in these inhibitors predispose to two scourges of modern humans. One, occurring most often in childhood, is a rare but deadly thrombomicroangiopathy called atypical hemolytic uremic syndrome. The other, age-related macular degeneration, is the most common form of blindness in the elderly. Their seemingly unrelated clinical presentations and pathologies share the common theme of overactivity of the complement system's alternative pathway. This review summarizes insights gained from contemporary genetics for understanding how dysregulation of this powerful innate immune system leads to these human diseases.
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Affiliation(s)
- M Kathryn Liszewski
- Division of Rheumatology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110;
| | - Anuja Java
- Division of Nephrology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | | | - John P Atkinson
- Division of Rheumatology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110;
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24
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Geerlings MJ, de Jong EK, den Hollander AI. The complement system in age-related macular degeneration: A review of rare genetic variants and implications for personalized treatment. Mol Immunol 2016; 84:65-76. [PMID: 27939104 PMCID: PMC5380947 DOI: 10.1016/j.molimm.2016.11.016] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/12/2016] [Accepted: 11/18/2016] [Indexed: 01/18/2023]
Abstract
The complement system plays a central role in age-related macular degeneration (AMD). Common and rare genetic variants in complement genes have been identified in AMD. Several of the rare variants affect the functioning of the complement system. However, a genetic association with AMD cannot always be proven. Functional assays can help identify patients for complement inhibiting therapies.
Age-related macular degeneration (AMD) is a progressive retinal disease and the major cause of irreversible vision loss in the elderly. Numerous studies have found both common and rare genetic variants in the complement pathway to play a role in the pathogenesis of AMD. In this review we provide an overview of rare variants identified in AMD patients, and summarize the functional consequences of rare genetic variation in complement genes on the complement system. Finally, we discuss the relevance of this work in light of ongoing clinical trials that study the effectiveness of complement inhibitors against AMD.
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Affiliation(s)
- Maartje J Geerlings
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Eiko K de Jong
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Anneke I den Hollander
- Department of Ophthalmology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands.
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25
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Roy N, Ohtani K, Hidaka Y, Amano Y, Matsuda Y, Mori K, Hwang I, Inoue N, Wakamiya N. Three pentraxins C-reactive protein, serum amyloid p component and pentraxin 3 mediate complement activation using Collectin CL-P1. Biochim Biophys Acta Gen Subj 2016; 1861:1-14. [PMID: 27864148 DOI: 10.1016/j.bbagen.2016.11.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/02/2016] [Accepted: 11/14/2016] [Indexed: 01/06/2023]
Abstract
BACKGROUND Pentraxins (PTXs) are a superfamily of multifunctional conserved proteins involved in acute-phase responses. Recently, we have shown that collectin placenta 1 (CL-P1) and C-reactive protein (CRP) mediated complement activation and failed to form terminal complement complex (TCC) in normal serum conditions because of complement factor H inhibition. METHODS We used CL-P1 expressing CHO/ldlA7 cells to study the interaction with PTXs. Soluble type CL-P1 was used in an ELISA assay for the binding, C3 and TCC deposition experiments. Furthermore, we used our previously established CL-P1 expressing HEK293 cells for the C3 fragment and TCC deposition assay. RESULTS We demonstrated that CL-P1 also bound serum amyloid p component (SAP) and pentraxin 3 (PTX3) to activate the classical pathway and the alternative pathway using factor B. CRP and PTX3 further amplified complement deposition by properdin. We found that CRP and PTX3 recruit CFH, whereas SAP recruits C4 binding protein on CL-P1 expressing cell surfaces to prevent the formation of TCC in normal serum conditions. In addition, depletion of CFH, C4BP and complement factor I (CFI) failed to prevent TCC formation both in ELISA and cell experiments. Furthermore, soluble complement receptor 1, an inhibitor of all complement pathways prevents PTX induced TCC formation. CONCLUSION Our current study hypothesizes that the interaction of pentraxins with CL-P1 is involved in complement activation. GENERAL SIGNIFICANCE CL-P1 might generally inhibit PTX induced complement activation and host damage to protect self-tissues.
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Affiliation(s)
- Nitai Roy
- Department of Microbiology & Immunochemistry, Asahikawa Medical University, Asahikawa 078-8510, Japan
| | - Katsuki Ohtani
- Department of Microbiology & Immunochemistry, Asahikawa Medical University, Asahikawa 078-8510, Japan
| | - Yoshihiko Hidaka
- Department of Pediatrics, School of Medicine, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
| | - Yoshiro Amano
- Department of Pediatrics, Nagano Red Cross Hospital, 5-22-1 Wakasato, Nagano 380-8582, Japan
| | - Yasuyuki Matsuda
- Department of Microbiology & Immunochemistry, Asahikawa Medical University, Asahikawa 078-8510, Japan
| | - Kenichiro Mori
- Department of Microbiology & Immunochemistry, Asahikawa Medical University, Asahikawa 078-8510, Japan
| | - Insu Hwang
- Department of Microbiology & Immunochemistry, Asahikawa Medical University, Asahikawa 078-8510, Japan
| | - Norimitsu Inoue
- Department of Tumor Immunology, Research Institute, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka 537-8511, Japan
| | - Nobutaka Wakamiya
- Department of Microbiology & Immunochemistry, Asahikawa Medical University, Asahikawa 078-8510, Japan.
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26
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Gleeson PJ, Wilson V, Cox TE, Sharma SD, Smith-Jackson K, Strain L, Lappin D, McHale T, Kavanagh D, Goodship THJ. Chromosomal rearrangement-A rare cause of complement factor I associated atypical haemolytic uraemic syndrome. Immunobiology 2016; 221:1124-30. [PMID: 27268256 DOI: 10.1016/j.imbio.2016.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 03/30/2016] [Accepted: 05/08/2016] [Indexed: 10/21/2022]
Abstract
Chromosomal rearrangements affecting the genes encoding complement factor H and the factor H related proteins have been described in aHUS patients. To date such disorders have not been described in other aHUS associated genes. We describe here a heterozygous 875,324bp deletion encompassing the gene (CFI) encoding complement factor I and ten other genes. The index case presented with aHUS and did not recover renal function. No abnormalities were detected on Sanger sequencing of CFI but a low factor I level led to a multiplex ligation-dependent probe amplification assay being undertaken. This showed a complete heterozygous deletion of CFI. The extent of the deletion and the breakpoint was defined. In the Newcastle aHUS cohort we have identified and report here 32 different CFI variants in 56 patients but to date this is the only deletion that we have identified. This finding although rare does suggest that screening for chromosomal rearrangements affecting CFI should be undertaken in all aHUS patients particularly if the factor I level is unexplainably low.
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Affiliation(s)
- Patrick J Gleeson
- Departments of Nephrology and Histopathology, University Hospital Galway, Galway, Ireland
| | - Valerie Wilson
- Northern Molecular Genetics Service, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Thomas E Cox
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Seema D Sharma
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Kate Smith-Jackson
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Lisa Strain
- Northern Molecular Genetics Service, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - David Lappin
- Departments of Nephrology and Histopathology, University Hospital Galway, Galway, Ireland
| | - Teresa McHale
- Departments of Nephrology and Histopathology, University Hospital Galway, Galway, Ireland
| | - David Kavanagh
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
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27
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Xiang J, Li X, Chen Y, Lu Y, Yu M, Chen X, Zhang W, Zeng Y, Sun L, Chen S, Sha Z. Complement factor I from flatfish half-smooth tongue (Cynoglossus semilaevis) exhibited anti-microbial activities. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2015; 53:199-209. [PMID: 26148855 DOI: 10.1016/j.dci.2015.06.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 05/30/2015] [Accepted: 06/06/2015] [Indexed: 06/04/2023]
Abstract
Complement factor I (Cfi) is a soluble serine protease which plays a crucial role in the modulation of complement cascades. In the presence of substrate modulating cofactors (such as complement factor H, C4bp, CR1, etc), Cfi cleaves and inactivates C3b and C4b, thereby controlling the complement-mediated processes. In this study, we sequenced and characterized Cfi gene from Cynoglossus Semilaevis (designated as CsCfi) for the first time. The full-length cDNA of CsCfi was 2230 bp in length, including a 98 bp 5'-untranslated region (UTR), a 164 bp 3'-UTR and a 1968 bp open reading frame (ORF). It encoded a polypeptide of 656 amino acids, with a molecular mass of 72.28 kDa and an isoelectric point of 7.71. A signal peptide was defined at N-terminus, resulting in a 626-residue mature protein. Multiple sequence alignment revealed that Cfi proteins were well conserved with the typical modular architecture and identical active sites throughout the vertebrates, which suggested the conserved function of Cfi. Phylogenetic analysis indicated that CsCfi and the homologous Cfi sequences from teleosts clustered into a clade, separating from another clade from the cartilaginous fish and other vertebrates. Tissue expression profile analysis by quantitative real-time PCR (qRT-PCR) showed that CsCfi mRNA constitutively expressed in all tested tissues, with the predominant expression in liver and the lowest in stomach. Temporal expression levels of CsCfi after challenging with Vibrio anguillarum showed different expression patterns in intestine, spleen, skin, blood, head kidney and liver. The recombinant CsCfi (rCsCfi) protein showed broad-spectrum antimicrobial activities against the Gram-positive bacteria Staphylococcus aureus and the Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa and Shewanella putrefaciens. The research revealed that CsCfi plays an important role in C. Semilaevis immunity.
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Affiliation(s)
- Jinsong Xiang
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Colleage of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China; Function Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, China
| | - Xihong Li
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, National Lab for Ocean Science and Technology, Qingdao 266235, China
| | - Yadong Chen
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, China
| | - Yang Lu
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, China
| | - Mengjun Yu
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, China; Colleage of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China
| | - Xuejie Chen
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Colleage of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China; Function Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, China
| | - Wenting Zhang
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Colleage of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China
| | - Yan Zeng
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Colleage of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China
| | - Luming Sun
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Colleage of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China
| | - Songlin Chen
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, National Lab for Ocean Science and Technology, Qingdao 266235, China
| | - Zhenxia Sha
- Key Laboratory for Sustainable Development of Marine Fisheries, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China; Function Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266235, China.
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Merle NS, Noe R, Halbwachs-Mecarelli L, Fremeaux-Bacchi V, Roumenina LT. Complement System Part II: Role in Immunity. Front Immunol 2015; 6:257. [PMID: 26074922 PMCID: PMC4443744 DOI: 10.3389/fimmu.2015.00257] [Citation(s) in RCA: 655] [Impact Index Per Article: 72.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 05/09/2015] [Indexed: 12/14/2022] Open
Abstract
The complement system has been considered for a long time as a simple lytic cascade, aimed to kill bacteria infecting the host organism. Nowadays, this vision has changed and it is well accepted that complement is a complex innate immune surveillance system, playing a key role in host homeostasis, inflammation, and in the defense against pathogens. This review discusses recent advances in the understanding of the role of complement in physiology and pathology. It starts with a description of complement contribution to the normal physiology (homeostasis) of a healthy organism, including the silent clearance of apoptotic cells and maintenance of cell survival. In pathology, complement can be a friend or a foe. It acts as a friend in the defense against pathogens, by inducing opsonization and a direct killing by C5b–9 membrane attack complex and by triggering inflammatory responses with the anaphylatoxins C3a and C5a. Opsonization plays also a major role in the mounting of an adaptive immune response, involving antigen presenting cells, T-, and B-lymphocytes. Nevertheless, it can be also an enemy, when pathogens hijack complement regulators to protect themselves from the immune system. Inadequate complement activation becomes a disease cause, as in atypical hemolytic uremic syndrome, C3 glomerulopathies, and systemic lupus erythematosus. Age-related macular degeneration and cancer will be described as examples showing that complement contributes to a large variety of conditions, far exceeding the classical examples of diseases associated with complement deficiencies. Finally, we discuss complement as a therapeutic target.
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Affiliation(s)
- Nicolas S Merle
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France
| | - Remi Noe
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France ; Ecole Pratique des Hautes Études (EPHE) , Paris , France
| | - Lise Halbwachs-Mecarelli
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France
| | - Veronique Fremeaux-Bacchi
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France ; Service d'Immunologie Biologique, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges-Pompidou , Paris , France
| | - Lubka T Roumenina
- UMRS 1138, Centre de Recherche des Cordeliers, INSERM , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Paris Cité, Université Paris Descartes , Paris , France ; UMRS 1138, Centre de Recherche des Cordeliers, Sorbonne Universités, UPMC Université Paris 06 , Paris , France
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Okroj M, Holmquist E, Nilsson E, Anagnostaki L, Jirström K, Blom AM. Local expression of complement factor I in breast cancer cells correlates with poor survival and recurrence. Cancer Immunol Immunother 2015; 64:467-78. [PMID: 25618258 PMCID: PMC11029147 DOI: 10.1007/s00262-015-1658-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/12/2015] [Indexed: 01/23/2023]
Abstract
Tumor cells often evade killing by the complement system by overexpressing membrane-bound complement inhibitors. However, production of soluble complement inhibitors in cells other than hepatocytes was rarely reported. We screened several breast cancer cell lines for expression of soluble complement inhibitor, complement factor I (FI). We also analyzed local production of FI in tissue microarrays with tumors from 130 breast cancer patients by in situ hybridization and immunohistochemistry. We found expression of FI in breast adenocarcinoma cell line MDA-MB-468 and confirmed its functional activity. Expression of FI at mRNA and protein levels was also confirmed in tumor cells and tumor stroma, both in fibroblasts and infiltrating immune cells. Multivariate Cox regression analyses revealed that high expression of FI protein in tumor cells was correlated with significantly shorter cancer-specific survival (HR 2.8; 95 % CI 1.0-7.5; p = 0.048) and recurrence-free survival (HR 3.4; 95 % CI 1.5-7.4; p = 0.002). High FI expression was positively correlated with tumor size (p < 0.001), and Nottingham histological grade (p = 0.015) and associated with estrogen and progesterone receptor status (p = 0.03 and p = 0.009, respectively). Our data show that FI is expressed in breast cancer and is associated with unfavorable clinical outcome.
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MESH Headings
- Adult
- Aged
- Aged, 80 and over
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Blotting, Western
- Breast Neoplasms/metabolism
- Breast Neoplasms/mortality
- Breast Neoplasms/pathology
- Carcinoma, Ductal, Breast/metabolism
- Carcinoma, Ductal, Breast/mortality
- Carcinoma, Ductal, Breast/pathology
- Complement Factor I/genetics
- Complement Factor I/metabolism
- Female
- Follow-Up Studies
- Humans
- Immunoenzyme Techniques
- In Situ Hybridization
- Middle Aged
- Neoplasm Recurrence, Local/metabolism
- Neoplasm Recurrence, Local/mortality
- Neoplasm Recurrence, Local/pathology
- Neoplasm Staging
- Prognosis
- RNA, Messenger/genetics
- Real-Time Polymerase Chain Reaction
- Receptors, Estrogen/genetics
- Receptors, Estrogen/metabolism
- Receptors, Progesterone/genetics
- Receptors, Progesterone/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Survival Rate
- Tissue Array Analysis
- Tumor Cells, Cultured
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Affiliation(s)
- Marcin Okroj
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Inga Maria Nilssons Street 53, Floor 4, 20502 Malmö, Sweden
- Laboratory Medicine, Clinical Chemistry, Region Skåne, Inga Maria Nilssons Street 53, 20502 Malmö, Sweden
| | - Emelie Holmquist
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Inga Maria Nilssons Street 53, Floor 4, 20502 Malmö, Sweden
| | - Elise Nilsson
- Section of Pathology, Department of Laboratory Medicine Malmö, Lund University, Jan Waldenström Street 59, 20502 Malmö, Sweden
| | - Lola Anagnostaki
- Laboratory Medicine, Clinical Pathology, Region Skåne, Jan Waldenström Street 59, 20502 Malmö, Sweden
| | - Karin Jirström
- Division of Oncology and Pathology, Department of Clinical Sciences Lund, Lund University, Sölvegatan 25, 22185 Lund, Sweden
| | - Anna M. Blom
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Inga Maria Nilssons Street 53, Floor 4, 20502 Malmö, Sweden
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Kavanagh D, Yu Y, Schramm EC, Triebwasser M, Wagner EK, Raychaudhuri S, Daly MJ, Atkinson JP, Seddon JM. Rare genetic variants in the CFI gene are associated with advanced age-related macular degeneration and commonly result in reduced serum factor I levels. Hum Mol Genet 2015; 24:3861-70. [PMID: 25788521 PMCID: PMC4459386 DOI: 10.1093/hmg/ddv091] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/09/2015] [Indexed: 12/13/2022] Open
Abstract
To assess a potential diagnostic and therapeutic biomarker for age-related macular degeneration (AMD), we sequenced the complement factor I gene (CFI) in 2266 individuals with AMD and 1400 without, identifying 231 individuals with rare genetic variants. We evaluated the functional impact by measuring circulating serum factor I (FI) protein levels in individuals with and without rare CFI variants. The burden of very rare (frequency <1/1000) variants in CFI was strongly associated with disease (P = 1.1 × 10−8). In addition, we examined eight coding variants with counts ≥5 and saw evidence for association with AMD in three variants. Individuals with advanced AMD carrying a rare CFI variant had lower mean FI compared with non-AMD subjects carrying a variant (P < 0.001). Further new evidence that FI levels drive AMD risk comes from analyses showing individuals with a CFI rare variant and low FI were more likely to have advanced AMD (P = 5.6 × 10−5). Controlling for covariates, low FI increased the risk of advanced AMD among those with a variant compared with individuals without advanced AMD with a rare CFI variant (OR 13.6, P = 1.6 × 10−4), and also compared with control individuals without a rare CFI variant (OR 19.0, P = 1.1 × 10−5). Thus, low FI levels are strongly associated with rare CFI variants and AMD. Enhancing FI activity may be therapeutic and measuring FI provides a screening tool for identifying patients who are most likely to benefit from complement inhibitory therapy.
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Affiliation(s)
- David Kavanagh
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Newcastle upon Tyne, UK
| | - Yi Yu
- Ophthalmic Epidemiology and Genetics Service, New England Eye Center, Tufts Medical Center, Boston, MA, USA
| | - Elizabeth C Schramm
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Michael Triebwasser
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Erin K Wagner
- Ophthalmic Epidemiology and Genetics Service, New England Eye Center, Tufts Medical Center, Boston, MA, USA
| | - Soumya Raychaudhuri
- Partners HealthCare Center for Personalized Genetic Medicine, Boston, MA, USA, Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA, Division of Genetics, 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
- Partners HealthCare Center for Personalized Genetic Medicine, Boston, MA, USA, Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA, Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA
| | - John P Atkinson
- Division of Rheumatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - 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 and Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, USA
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Alasfar S, Alachkar N. Atypical hemolytic uremic syndrome post-kidney transplantation: two case reports and review of the literature. Front Med (Lausanne) 2014; 1:52. [PMID: 25593925 PMCID: PMC4292050 DOI: 10.3389/fmed.2014.00052] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 11/29/2014] [Indexed: 01/09/2023] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare disorder characterized by over-activation and dysregulation of the alternative complement pathway. Its estimated prevalence is 1–2 per million. The disease is characterized by thrombotic microangiopathy, which causes anemia, thrombocytopenia, and acute renal failure. aHUS has more severe course compared to typical (infection-induced) HUS and is frequently characterized by relapses that leads to end stage renal disease. For a long time, kidney transplantation for these patients was contraindicated because of high rate of recurrence and subsequent renal graft loss. The post-kidney transplantation recurrence rate largely depends on the pathogenetic mechanisms involved. However, over the past several years, advancements in the understanding and therapeutics of aHUS have allowed successful kidney transplantation in these patients. Eculizumab, which is a complement C5 antibody that inhibits complement factor 5a and subsequent formation of the membrane-attack complex, has been used in prevention and treatment of post-transplant aHUS recurrence. In this paper, we present two new cases of aHUS patients who underwent successful kidney transplantation in our center with the use of prophylactic and maintenance eculizumab therapy that have not been published before. The purpose of reporting these two cases is to emphasize the importance of using eculizumab as a prophylactic therapy to prevent aHUS recurrence post-transplant in high-risk patients. We will also review the current understanding of the genetics of aHUS, the pathogenesis of its recurrence after kidney transplantation, and strategies for prevention and treatment of post-transplant aHUS recurrence.
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Affiliation(s)
- Sami Alasfar
- Department of Medicine, Division of Nephrology, The Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Nada Alachkar
- Department of Medicine, Division of Nephrology, The Johns Hopkins University School of Medicine , Baltimore, MD , USA
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Syndrome hémolytique et urémique atypique : pour qui l’éculizumab ? MEDECINE INTENSIVE REANIMATION 2014. [DOI: 10.1007/s13546-014-0928-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abstract
Hemolytic uremic syndrome (HUS) is a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. The atypical form of HUS is a disease characterized by complement overactivation. Inherited defects in complement genes and acquired autoantibodies against complement regulatory proteins have been described. Incomplete penetrance of mutations in all predisposing genes is reported, suggesting that a precipitating event or trigger is required to unmask the complement regulatory deficiency. The underlying genetic defect predicts the prognosis both in native kidneys and after renal transplantation. The successful trials of the complement inhibitor eculizumab in the treatment of atypical HUS will revolutionize disease management.
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Affiliation(s)
- David Kavanagh
- The Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.
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Abstract
Factor I (FI) is a soluble, 88 kDa glycoprotein present in plasma at a concentration of approximately 35 mg/L. FI inhibits all complement pathways as it degrades activated C4b and C3b when these are bound to a cofactor such as C4b-binding protein or factor H. Here, we describe a method for purification of FI from human plasma, which is based on affinity chromatography followed by anion exchange chromatography. We also describe a functional assay, in which activity of FI can be assessed.
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Affiliation(s)
- Sara C Nilsson
- Department of Laboratory Medicine, Section of Medical Protein Chemistry, The Wallenberg Laboratory, Lund University, Skåne University Hospital, Malmö, Sweden
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35
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Haerynck F, Stordeur P, Vandewalle J, Van Coster R, Bordon V, De Baets F, Schelstraete P, Javaux C, Bouvry MR, Fremeaux-Bacchi V, Dehoorne J. Complete Factor I Deficiency Due to Dysfunctional Factor I with Recurrent Aseptic Meningo-Encephalitis. J Clin Immunol 2013; 33:1293-301. [DOI: 10.1007/s10875-013-9944-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 09/30/2013] [Indexed: 11/29/2022]
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Salvadori M, Bertoni E. Update on hemolytic uremic syndrome: Diagnostic and therapeutic recommendations. World J Nephrol 2013; 2:56-76. [PMID: 24255888 PMCID: PMC3832913 DOI: 10.5527/wjn.v2.i3.56] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 06/26/2013] [Accepted: 08/13/2013] [Indexed: 02/06/2023] Open
Abstract
Hemolytic uremic syndrome (HUS) is a rare disease. In this work the authors review the recent findings on HUS, considering the different etiologic and pathogenetic classifications. New findings in genetics and, in particular, mutations of genes that encode the complement-regulatory proteins have improved our understanding of atypical HUS. Similarly, the complement proteins are clearly involved in all types of thrombotic microangiopathy: typical HUS, atypical HUS and thrombotic thrombocytopenic purpura (TTP). Furthermore, several secondary HUS appear to be related to abnormalities in complement genes in predisposed patients. The authors highlight the therapeutic aspects of this rare disease, examining both “traditional therapy” (including plasma therapy, kidney and kidney-liver transplantation) and “new therapies”. The latter include anti-Shiga-toxin antibodies and anti-C5 monoclonal antibody “eculizumab”. Eculizumab has been recently launched for the treatment of the atypical HUS, but it appears to be effective in the treatment of typical HUS and in TTP. Future therapies are in phases I and II. They include anti-C5 antibodies, which are more purified, less immunogenic and absorbed orally and, anti-C3 antibodies, which are more powerful, but potentially less safe. Additionally, infusions of recombinant complement-regulatory proteins are a potential future therapy.
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Wong EKS, Goodship THJ, Kavanagh D. Complement therapy in atypical haemolytic uraemic syndrome (aHUS). Mol Immunol 2013; 56:199-212. [PMID: 23810412 PMCID: PMC3899040 DOI: 10.1016/j.molimm.2013.05.224] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Accepted: 05/10/2013] [Indexed: 12/22/2022]
Abstract
Central to the pathogenesis of atypical haemolytic uraemic syndrome (aHUS) is over-activation of the alternative pathway of complement. Inherited defects in complement genes and autoantibodies against complement regulatory proteins have been described. The use of plasma exchange to replace non-functioning complement regulators and hyper-functional complement components in addition to the removal of CFH-autoantibodies made this the ‘gold-standard’ for management of aHUS. In the last 4 years the introduction of the complement inhibitor Eculizumab has revolutionised the management of aHUS. In this review we shall discuss the available literature on treatment strategies to date.
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Affiliation(s)
- Edwin K S Wong
- The Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
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Eculizumab in the treatment of atypical haemolytic uraemic syndrome and other complement-mediated renal diseases. Curr Opin Pediatr 2013; 25:225-31. [PMID: 23486421 DOI: 10.1097/mop.0b013e32835df4a3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW This review considers the use of eculizumab in the treatment of atypical haemolytic uraemic syndrome (aHUS) as well as the other complement-mediated renal diseases, including dense deposit disease (DDD) and C3 glomerulonephritis (C3GN). In addition, a brief discussion of the effectiveness of eculizumab for the prevention of antibody-mediated rejection (AMR) in the setting of renal transplant and the treatment of shiga toxin associated haemolytic uraemic syndrome (STEC HUS) is also provided. RECENT FINDINGS No randomized controlled trials exist to support the use of eculizumab in renal disease. The results of two unpublished, prospective adult and adolescent trials support its utility in aHUS, whereas retrospective data support the effectiveness in paediatric aHUS. These two data sets form the basis of the sole renal indication for eculizumab. One small, single-centre trial and a growing number of case reports support the use of eculizumab in C3 glomerulopathy (C3G). There are limited trial data in AMR and renal transplant. Finally, there are conflicting data for the use of eculizumab in STEC HUS. SUMMARY The cumulative published data establish the effectiveness of eculizumab in a select group of renal diseases that have at the centre of their disease either abnormal complement control or maladaptive complement activation.
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Broderick L, Gandhi C, Mueller JL, Putnam CD, Shayan K, Giclas PC, Peterson KS, Aceves SS, Sheets RM, Peterson BM, Newbury RO, Hoffman HM, Bastian JF. Mutations of complement factor I and potential mechanisms of neuroinflammation in acute hemorrhagic leukoencephalitis. J Clin Immunol 2012; 33:162-71. [PMID: 22926405 DOI: 10.1007/s10875-012-9767-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 08/09/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE Acute Hemorrhagic Leukoencephalitis (AHLE) is a rare demyelinating disorder of acute onset, rapid deterioration and significant morbidity and mortality. Most often described as a post-infectious complication of an upper respiratory illness, its precise pathophysiology remains unclear. We describe two pediatric patients with AHLE with partial complement factor I (FI) deficiency whose successful treatment included the interleukin-1 (IL-1) receptor antagonist, anakinra, implicating a role for FI and IL-1 in this disorder. METHODS Extensive clinical workup of two patients presenting with AHLE revealed complement abnormalities, specifically related to the alternative pathway and its regulator, FI. Aggressive management with steroids, immunoglobulin, and anakinra ultimately led to improvement of clinical status and near return to neurologic baseline in both patients. Genetic sequencing of the FI coding regions of the patients and their families was performed. In vitro protein expression studies and immunohistochemistry of fixed brain tissue was used to investigate pathogenic mechanisms. RESULTS Two novel mutations in FI were identified in our patients, which result in failure to secrete FI. Immunohistochemical evaluation of brain tissue demonstrated positive staining for C3, membrane attack complex (MAC) and IL-1. CONCLUSIONS We propose AHLE is an unreported, rare phenotype for partial FI deficiency. The upregulation of C3, MAC and IL-1 with subsequent demyelination support a pathologic role for complement activation in AHLE, and suggest anakinra as an important adjunctive therapy in this disease.
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Affiliation(s)
- Lori Broderick
- Division of Rheumatology, Allergy and Immunology, Department of Medicine, University of California-San Diego, 9500 Gilman Dr. MC 0635, La Jolla, CA 92093, USA
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Servais A, Noël LH, Roumenina LT, Le Quintrec M, Ngo S, Dragon-Durey MA, Macher MA, Zuber J, Karras A, Provot F, Moulin B, Grünfeld JP, Niaudet P, Lesavre P, Frémeaux-Bacchi V. Acquired and genetic complement abnormalities play a critical role in dense deposit disease and other C3 glomerulopathies. Kidney Int 2012; 82:454-64. [PMID: 22456601 DOI: 10.1038/ki.2012.63] [Citation(s) in RCA: 375] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Dense deposit disease and glomerulonephritis with isolated C3 deposits are glomerulopathies characterized by deposits of C3 within or along the glomerular basement membrane. Previous studies found a link between dysregulation of the complement alternative pathway and the pathogenesis of these diseases. We analyzed the role of acquired and genetic complement abnormalities in a cohort of 134 patients, of whom 29 have dense deposit disease, 56 have glomerulonephritis with isolated C3 deposits, and 49 have primary membranoproliferative glomerulonephritis type I, with adult and pediatric onset. A total of 53 patients presented with a low C3 level, and 65 were positive for C3 nephritic factor that was significantly more frequently detected in patients with dense deposit disease than in other histological types. Mutations in CFH and CFI genes were identified in 24 patients associated with a C3 nephritic factor in half the cases. We found evidence for complement alternative pathway dysregulation in 26 patients with membranoproliferative glomerulonephritis type I. The complement factor H Y402H variant was significantly increased in dense deposit disease. We identified one at-risk membrane cofactor protein (MCP) haplotype for glomerulonephritis with isolated C3 deposits and membranoproliferative glomerulonephritis type I. Thus, our results suggest a critical role of fluid-phase alternative pathway dysregulation in the pathogenesis of C3 glomerulopathies as well as in immune complex-mediated glomerular diseases. The localization of the C3 deposits may be under the influence of MCP expression.
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Affiliation(s)
- Aude Servais
- Department of Nephrology, Hôpital Necker-Enfants Malades AP-HP, Paris, France.
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41
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Sanchez-Gallego JI, Groeneveld TWL, Krentz S, Nilsson SC, Villoutreix BO, Blom AM. Analysis of binding sites on complement factor I using artificial N-linked glycosylation. J Biol Chem 2012; 287:13572-83. [PMID: 22393059 DOI: 10.1074/jbc.m111.326298] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Factor I (FI) is a serine protease that inhibits all complement pathways by degrading activated complement components C3b and C4b. FI functions only in the presence of several cofactors, such as factor H, C4b-binding protein, complement receptor 1, and membrane cofactor protein. FI is composed of two chains linked by a disulfide bridge; the light chain comprises only the serine protease (SP) domain, whereas the heavy chain contains the FI membrane attack complex domain (FIMAC), CD5 domain, and low density lipoprotein receptor 1 (LDLr1) and LDLr2 domains. To better understand how FI inhibits complement, we used homology-based three-dimensional models of FI domains in an attempt to identify potential protein-protein interaction sites. Specific amino acids were then mutated to yield 20 recombinant mutants of FI carrying additional surface-exposed N-glycosylation sites that were expected to sterically hinder interactions. The Michaelis constant (K(m)) of all FI mutants toward a small substrate was not increased. We found that many mutations in the FIMAC and SP domains nearly abolished the ability of FI to degrade C4b and C3b in the fluid phase and on the surface, irrespective of the cofactor used. On the other hand, only a few alterations in the CD5 and LDLr1/2 domains impaired this activity. In conclusion, all analyzed cofactors form similar trimolecular complexes with FI and C3b/C4b, and the accessibility of FIMAC and SP domains is crucial for the function of FI.
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Affiliation(s)
- Jose I Sanchez-Gallego
- Department of Laboratory Medicine, Medical Protein Chemistry, Malmö University Hospital, Lund University, S-205 02 Malmö, Sweden
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Kavanagh D, Pappworth IY, Anderson H, Hayes CM, Moore I, Hunze EM, Bennaceur K, Roversi P, Lea S, Strain L, Ward R, Plant N, Nailescu C, Goodship THJ, Marchbank KJ. Factor I autoantibodies in patients with atypical hemolytic uremic syndrome: disease-associated or an epiphenomenon? Clin J Am Soc Nephrol 2012; 7:417-26. [PMID: 22223611 DOI: 10.2215/cjn.05750611] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND OBJECTIVES Atypical hemolytic uremic syndrome is a disease associated with mutations in the genes encoding the complement regulators factors H and I. In addition, factor H autoantibodies have been reported in ∼10% of patients with atypical hemolytic uremic syndrome. This study searched for the presence of factor I autoantibodies in atypical hemolytic uremic syndrome. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study screened 175 atypical hemolytic uremic syndrome patients for factor I autoantibodies using ELISA with confirmatory Western blotting. Functional studies using purified immunoglobulin from one patient were subsequently undertaken. RESULTS Factor I autoantibodies were detected in three patients. In one patient with a high titer of autoantibody, the titer was tracked over time and was found to have no association with disease activity. This study found evidence of an immune complex of antibody and factor I in this patient, but purified IgG, isolated from current serum samples, had only a minor effect on fluid phase and cell surface complement regulation. Genetic analysis of the three patients with factor I autoantibodies revealed that they had two copies of the genes encoding factor H-related proteins 1 and 3 and therefore, did not have a deletion commonly associated with factor H autoantibodies in atypical hemolytic uremic syndrome. Two patients, however, had functionally significant mutations in complement factor H. CONCLUSIONS These findings reinforce the concept of multiple concurrent risk factors being associated with atypical hemolytic uremic syndrome but question whether autoantibodies per se predispose to atypical hemolytic uremic syndrome.
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Affiliation(s)
- David Kavanagh
- Institutes of Cellular and Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom
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Ermini L, Goodship TH, Strain L, Weale ME, Sacks SH, Cordell HJ, Fremeaux-Bacchi V, Sheerin NS. Common genetic variants in complement genes other than CFH, CD46 and the CFHRs are not associated with aHUS. Mol Immunol 2012; 49:640-8. [PMID: 22153652 PMCID: PMC3438446 DOI: 10.1016/j.molimm.2011.11.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 11/10/2011] [Indexed: 01/15/2023]
Abstract
It is well established that common genetic variants in CFH, CD46 and the CFHRs are additional risk factors for the development of aHUS. To examine the hypothesis that common variants in other complement genes have a similar effect we genotyped 501 SNPs in 47 complement genes in 94 aHUS patients from Newcastle, 126 aHUS patients from Paris, 374 UK controls and 165 French controls. We replicated the associations in CFH, CD46 and the CFHRs but found no association with any other complement gene. The strongest associations replicated in both cohorts were found for four SNPs within CD46 (p-value<10(-3)) and five SNPs within CFH (p-value<5×10(-3)). Significant replicable associations with single SNPs in CFHR2, CFHR4 and an intergenic SNP (CR1-CD46) were also found. Analysis of the Paris cohort showed that the association with CD46 SNPs was only present in those patients with complement mutations. Haplotype analysis showed at-risk and protective haplotypes in both CD46 and CFH. The CD46 haplotype was only disease-associated in those patients with mutations.
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Affiliation(s)
- Luca Ermini
- Institute of Cellular Medicine, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Timothy H.J. Goodship
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Lisa Strain
- Northern Molecular Genetics Service, Newcastle upon Tyne Hospitals NHS Foundation Trust, United Kingdom
| | - Michael E. Weale
- Department of Medical and Molecular Genetics, King's College London, Guy's Hospital, London SE1 9RT, United Kingdom
| | - Steven H. Sacks
- MRC Centre for Transplantation, King's College London, School of Medicine at Guy's, King's and St. Thomas’ Hospitals, London, United Kingdom
| | - Heather J. Cordell
- Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne NE2 4HH, United Kingdom
| | - Veronique Fremeaux-Bacchi
- Assistance Publique-Hopitaux de Paris, Hôpital Européen Georges-Pompidou, Service d‘Immunologie Biologique, Paris, France
| | - Neil S. Sheerin
- Institute of Cellular Medicine, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, United Kingdom
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Abstract
Hemolytic uremic syndrome (HUS) is defined by the triad of mechanical hemolytic anemia, thrombocytopenia and renal impairment. Atypical HUS (aHUS) defines non Shiga-toxin-HUS and even if some authors include secondary aHUS due to Streptococcus pneumoniae or other causes, aHUS designates a primary disease due to a disorder in complement alternative pathway regulation. Atypical HUS represents 5 -10% of HUS in children, but the majority of HUS in adults. The incidence of complement-aHUS is not known precisely. However, more than 1000 aHUS patients investigated for complement abnormalities have been reported. Onset is from the neonatal period to the adult age. Most patients present with hemolytic anemia, thrombocytopenia and renal failure and 20% have extra renal manifestations. Two to 10% die and one third progress to end-stage renal failure at first episode. Half of patients have relapses. Mutations in the genes encoding complement regulatory proteins factor H, membrane cofactor protein (MCP), factor I or thrombomodulin have been demonstrated in 20-30%, 5-15%, 4-10% and 3-5% of patients respectively, and mutations in the genes of C3 convertase proteins, C3 and factor B, in 2-10% and 1-4%. In addition, 6-10% of patients have anti-factor H antibodies. Diagnosis of aHUS relies on 1) No associated disease 2) No criteria for Shigatoxin-HUS (stool culture and PCR for Shiga-toxins; serology for anti-lipopolysaccharides antibodies) 3) No criteria for thrombotic thrombocytopenic purpura (serum ADAMTS 13 activity > 10%). Investigation of the complement system is required (C3, C4, factor H and factor I plasma concentration, MCP expression on leukocytes and anti-factor H antibodies; genetic screening to identify risk factors). The disease is familial in approximately 20% of pedigrees, with an autosomal recessive or dominant mode of transmission. As penetrance of the disease is 50%, genetic counseling is difficult. Plasmatherapy has been first line treatment until presently, without unquestionable demonstration of efficiency. There is a high risk of post-transplant recurrence, except in MCP-HUS. Case reports and two phase II trials show an impressive efficacy of the complement C5 blocker eculizumab, suggesting it will be the next standard of care. Except for patients treated by intensive plasmatherapy or eculizumab, the worst prognosis is in factor H-HUS, as mortality can reach 20% and 50% of survivors do not recover renal function. Half of factor I-HUS progress to end-stage renal failure. Conversely, most patients with MCP-HUS have preserved renal function. Anti-factor H antibodies-HUS has favourable outcome if treated early.
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45
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Complement factor I in health and disease. Mol Immunol 2011; 48:1611-20. [DOI: 10.1016/j.molimm.2011.04.004] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 04/06/2011] [Accepted: 04/06/2011] [Indexed: 02/02/2023]
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Abstract
Complement is a part of the body's innate immune system that helps defend the host from microbial infection. It is tightly controlled by a number of cell surface and fluid-phase proteins so that under normal circumstances injury to autologous tissues is avoided. In many pathological settings, such as when the complement regulatory mechanisms are dysfunctional or overwhelmed, complement attack of autologous tissues can occur with severe, sometimes life-threatening consequences. The kidney appears to be particularly vulnerable to complement-mediated inflammatory injury and many kidney pathologies have been linked to abnormal complement activation. Clinical and experimental studies have shown that complement attack can be a primary cause in rare, genetically predisposed kidney diseases or a significant contributor to kidney injury caused by other etiological factors. Here we provide a brief review of recent advances on the activation and regulation of the complement system in kidney disease, with a particular emphasis on the relevance of complement regulatory proteins.
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Affiliation(s)
- Allison M Lesher
- Institute for Translational Medicine and Therapeutics and Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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47
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Schejbel L, Schmidt IM, Kirchhoff M, Andersen CB, Marquart HV, Zipfel P, Garred P. Complement factor H deficiency and endocapillary glomerulonephritis due to paternal isodisomy and a novel factor H mutation. Genes Immun 2011; 12:90-9. [PMID: 21270828 DOI: 10.1038/gene.2010.63] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Complement factor H (CFH) is a regulator of the alternative complement activation pathway. Mutations in the CFH gene are associated with atypical hemolytic uremic syndrome, membranoproliferative glomerulonephritis type II and C3 glomerulonephritis. Here, we report a 6-month-old CFH-deficient child presenting with endocapillary glomerulonephritis rather than membranoproliferative glomerulonephritis (MPGN) or C3 glomerulonephritis. Sequence analyses showed homozygosity for a novel CFH missense mutation (Pro139Ser) associated with severely decreased CFH plasma concentration (<6%) but normal mRNA splicing and expression. The father was heterozygous carrier of the mutation, but the mother was a non-carrier. Thus, a large deletion in the maternal CFH locus or uniparental isodisomy was suspected. Polymorphic markers across chromosome 1 showed homozygosity for the paternal allele in all markers and a lack of the maternal allele in six informative markers. This combined with a comparative genomic hybridization assay demonstrated paternal isodisomy. Uniparental isodisomy increases the risk of homozygous variations in other genes on the affected chromosome. Therefore, we analyzed other susceptibility genes on chromosome 1 and found no sequence variation in membrane cofactor protein, but homozygosity for the common deletion of CFH-related proteins 1 and 3, which may contribute to the early onset of disease.
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Affiliation(s)
- L Schejbel
- Department of Clinical Immunology, Laboratory of Molecular Medicine, Rigshospitalet, Copenhagen, Denmark.
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48
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Roumenina LT, Loirat C, Dragon-Durey MA, Halbwachs-Mecarelli L, Sautes-Fridman C, Fremeaux-Bacchi V. Alternative complement pathway assessment in patients with atypical HUS. J Immunol Methods 2011; 365:8-26. [PMID: 21215749 DOI: 10.1016/j.jim.2010.12.020] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 10/31/2010] [Accepted: 12/30/2010] [Indexed: 01/02/2023]
Abstract
The atypical Hemolytic Uremic Syndrome (aHUS) is a rare thrombotic microangiopathy leading to end stage renal disease in approximately 60% of patients. Over the last decade, a clear link has been demonstrated between this disease and defective complement regulation. The hallmark of the aHUS is the association with mutations in complement alternative pathway genes. Endothelial damage is related to complement dysregulation, but the exact mechanism is just starting to be elucidated. Screening for and characterization of mutations in the components of the C3 convertase (C3 and FB) or its regulators (FH, FI, MCP, and Thrombomodulin) or anti-FH antibodies has become an indispensable part of the disease's diagnostic. This review will initially summarize current knowledge on the understanding of complement activation and regulation, followed by a description on the genetic analysis as well as the methods used for complement protein quantification. Another part of this review will focus on the mechanisms of action of aHUS-associated mutations. We will emphasize on when and why some mutations lead to protein deficiency, while others result in - to dysfunctional but normally expressed proteins. Finally, we will discuss how the therapy of aHUS patients can be modified according to the functional consequences of each particular genetic defect.
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49
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Waters AM, Licht C. aHUS caused by complement dysregulation: new therapies on the horizon. Pediatr Nephrol 2011; 26:41-57. [PMID: 20556434 PMCID: PMC2991208 DOI: 10.1007/s00467-010-1556-4] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2010] [Revised: 04/23/2010] [Accepted: 04/26/2010] [Indexed: 12/19/2022]
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a heterogeneous disease that is caused by defective complement regulation in over 50% of cases. Mutations have been identified in genes encoding both complement regulators [complement factor H (CFH), complement factor I (CFI), complement factor H-related proteins (CFHR), and membrane cofactor protein (MCP)], as well as complement activators [complement factor B (CFB) and C3]. More recently, mutations have also been identified in thrombomodulin (THBD), an anticoagulant glycoprotein that plays a role in the inactivation of C3a and C5a. Inhibitory autoantibodies to CFH account for an additional 5-10% of cases and can occur in isolation or in association with mutations in CFH, CFI, CFHR 1, 3, 4, and MCP. Plasma therapies are considered the mainstay of therapy in aHUS secondary to defective complement regulation and may be administered as plasma infusions or plasma exchange. However, in certain cases, despite initiation of plasma therapy, renal function continues to deteriorate with progression to end-stage renal disease and renal transplantation. Recently, eculizumab, a humanized monoclonal antibody against C5, has been described as an effective therapeutic strategy in the management of refractory aHUS that has failed to respond to plasma therapy. Clinical trials are now underway to further evaluate the efficacy of eculizumab in the management of both plasma-sensitive and plasma-resistant aHUS.
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Affiliation(s)
- Aoife M. Waters
- Department of Nephrology, Great Ormond Street Hospital, London, WC1N 3JH UK ,University College London, Institute of Child Health, London, UK
| | - Christoph Licht
- Division of Nephrology, Hospital for Sick Children, Toronto, ON Canada ,Department of Paediatrics, University of Toronto, Toronto, ON Canada
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50
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Abstract
Central to the pathogenesis of atypical hemolytic uremic syndrome (aHUS) is over-activation of the alternative pathway of complement. Following the initial discovery of mutations in the complement regulatory protein, factor H, mutations have been described in factor I, membrane cofactor protein and thrombomodulin, which also result in decreased complement regulation. Autoantibodies to factor H have also been reported to impair complement regulation in aHUS. More recently, gain of function mutations in the complement components C3 and Factor B have been seen. This review focuses on the genetic causes of aHUS, their functional consequences, and clinical effect.
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