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Azoulay E, Zuber J, Bousfiha AA, Long Y, Tan Y, Luo S, Essafti M, Annane D. Complement system activation: bridging physiology, pathophysiology, and therapy. Intensive Care Med 2024:10.1007/s00134-024-07611-4. [PMID: 39254734 DOI: 10.1007/s00134-024-07611-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Accepted: 08/10/2024] [Indexed: 09/11/2024]
Abstract
The complement system is a set of over 50 proteins that constitutes an essential part of the innate immune system. Complement system activation involves an organized proteolytic cascade. Overactivation of complement system activation is the main pathogenic mechanism of several diseases and contributes to the manifestations of many other conditions. This review describes the normal complement system and the role for complement dysregulation in critical illnesses, notably sepsis and acute respiratory distress syndrome. Complement activation is involved in the immune system response to pathogens but, when excessive, can contribute to tissue damage, runaway inflammation, and capillary leakage syndrome. Complement overactivation may play a key role in severe forms of coronavirus disease 2019 (COVID-19). Two diseases whose manifestations are mainly caused by complement overactivation, namely, atypical hemolytic and uremic syndrome (aHUS) and myasthenia gravis, are discussed. A diagnostic algorithm for aHUS is provided. Early complement-inhibiting therapy has been proven effective. When renal transplantation is required, complement-inhibiting drugs can be used prophylactically to prevent aHUS recurrence. Similarly, acetylcholine-receptor autoantibody-positive generalized myasthenia gravis involves complement system overactivation and responds to complement inhibition. The two main complement inhibitors used in to date routine are eculizumab and ravulizumab. The main adverse event is Neisseria infection, which is rare and preventable, but can be fatal. The complement system is crucial to health but, when overactivated, can cause or contribute to disease. Effective complement inhibitors are now available, although additional data are required to determine optimal regimens. Further research is also needed to better understand the complement system, develop advanced diagnostic tools, and identify markers that allow the personalization of treatment strategies.
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Affiliation(s)
- Elie Azoulay
- Intensive Care Unit, Saint-Louis University Hospital, AP-HP, Paris Cité University, Paris, France.
| | - Julien Zuber
- Department of Kidney and Metabolic Diseases, Transplantation and Clinical Immunology, Necker University Hospital, AP-HP, Paris, France
| | - Ahmed Aziz Bousfiha
- Department of Pediatric Infectious and Immunological Diseases, IbnRochd University Hospital, Casablanca, Morocco
- Laboratory of Clinical Immunology, Inflammation and Allergy (LICIA), Casablanca, Morocco
- School of Medicine and Pharmacy, Hassan II University, Casablanca, Morocco
| | - Yun Long
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Disease, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Ying Tan
- Renal Division, Department of Medicine, Peking University First Hospital, Beijing, PR China
- Institute of Nephrology, Peking University, Beijing, PR China
- Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, PR China
| | - Sushan Luo
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, PR China
- Huashan Rare Diseases Center, Huashan Hospital, Fudan University, Shanghai, PR China
- National Center for Neurological Diseases, Shanghai, PR China
| | - Meriem Essafti
- Intensive Care Department, Mother-Children Center, Mohamed VI University Hospital, Marrakech, Morocco
| | - Djillali Annane
- Department of Intensive Care, Raymond Poincaré Hospital, AP-HP, Garches, France
- Simone Veil School of Medicine, Versailles-Saint Quentin University, Paris-Saclay University, Versaillles, France
- Institut Hospitalo-Universitaire PROMETHEUS & Fédération Hospitalo-Universitaire SEPSIS, Paris-Saclay University, Saclay, France
- INSERM, Garches, France
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Tsuchida M, Goto S, Watanabe H, Goto S, Yamaguchi H, Narita I. Defective C3d caused by C3 p.W1034R in inherited atypical hemolytic uremic syndrome. Mol Genet Genomic Med 2024; 12:e2288. [PMID: 37795781 PMCID: PMC10767574 DOI: 10.1002/mgg3.2288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 09/12/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023] Open
Abstract
INTRODUCTION Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy. Personal genome analyses have revealed numerous aHUS-causing variants, mainly complement-related genes. However, not all aHUS-causing variants have been functionally validated. METHODS An exome sequence analysis of a Japanese multiplex family composed of three patients diagnosed with aHUS in infancy and showing frequent relapses clustered in a dominant transmission mode was performed. Protein interaction between the C3d and C-terminal domains of factor H was analyzed using a quartz crystal microbalance. RESULTS Following filtering by heterozygous variants, amino acid substitutions, and allele frequency, the analysis revealed eight rare variants shared by the affected individuals. Variant prioritization listed C3 p.W1034R as the most likely candidate gene mutation in the affected individuals, despite being classified as a variant of uncertain significance. Binding of recombinant C3d harboring 1034R to recombinant short consensus repeats 15 to 20 of factor H was significantly suppressed compared with that of C3 with 1034W. CONCLUSION C3 p.W1034R results in an inherited form of aHUS that often presents with recurrent episodes, possibly because of impaired interactions between the C3d and C-terminal domains of factor H. Following comprehensive genomic analysis, functional validation of C3 p.W1034R strengthens the molecular basis for aHUS pathophysiology.
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Affiliation(s)
- Masafumi Tsuchida
- Division of Clinical Nephrology and Rheumatology, Kidney Research CenterNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
| | - Shin Goto
- Division of Clinical Nephrology and Rheumatology, Kidney Research CenterNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
| | - Hirofumi Watanabe
- Division of Clinical Nephrology and Rheumatology, Kidney Research CenterNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
| | - Sawako Goto
- Department of Applied Molecular Medicine, Kidney Research CenterNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
| | - Hiroki Yamaguchi
- Division of Clinical Nephrology and Rheumatology, Kidney Research CenterNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
| | - Ichiei Narita
- Division of Clinical Nephrology and Rheumatology, Kidney Research CenterNiigata University Graduate School of Medical and Dental SciencesNiigataJapan
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Heurich M, McCluskey G. Complement and coagulation crosstalk - Factor H in the spotlight. Immunobiology 2023; 228:152707. [PMID: 37633063 DOI: 10.1016/j.imbio.2023.152707] [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: 04/11/2023] [Revised: 07/02/2023] [Accepted: 07/10/2023] [Indexed: 08/28/2023]
Abstract
The immune complement and the coagulation systems are blood-based proteolytic cascades that are activated by pathway-specific triggers, based on protein-protein interactions and enzymatic cleavage reactions. Activation of these systems is finely balanced and controlled through specific regulatory mechanisms. The complement and coagulation systems are generally viewed as distinct, but have common evolutionary origins, and several interactions between these homologous systems have been reported. This complement and coagulation crosstalk can affect activation, amplification and regulatory functions in both systems. In this review, we summarize the literature on coagulation factors contributing to complement alternative pathway activation and regulation and highlight molecular interactions of the complement alternative pathway regulator factor H with several coagulation factors. We propose a mechanism where factor H interactions with coagulation factors may contribute to both complement and coagulation activation and regulation within the haemostatic system and fibrin clot microenvironment and introduce the emerging role of factor H as a modulator of coagulation. Finally, we discuss the potential impact of these protein interactions in diseases associated with factor H dysregulation or deficiency as well as evidence of coagulation dysfunction.
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Affiliation(s)
- Meike Heurich
- School of Pharmacy and Pharmaceutical Sciences, College of Biomedical and Life Sciences, Cardiff University, United Kingdom.
| | - Geneviève McCluskey
- Université Paris-Saclay, INSERM, Hémostase, Inflammation, Thrombose HITH U1176, 94276 Le Kremlin-Bicêtre, France
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Brocklebank V, Walsh PR, Smith-Jackson K, Hallam TM, Marchbank KJ, Wilson V, Bigirumurame T, Dutt T, Montgomery EK, Malina M, Wong EKS, Johnson S, Sheerin NS, Kavanagh D. Atypical hemolytic uremic syndrome in the era of terminal complement inhibition: an observational cohort study. Blood 2023; 142:1371-1386. [PMID: 37369098 PMCID: PMC10651868 DOI: 10.1182/blood.2022018833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 05/11/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
Historically, the majority of patients with complement-mediated atypical hemolytic uremic syndrome (CaHUS) progress to end-stage kidney disease (ESKD). Single-arm trials of eculizumab with a short follow-up suggested efficacy. We prove, for the first time to our knowledge, in a genotype matched CaHUS cohort that the 5-year cumulative estimate of ESKD-free survival improved from 39.5% in a control cohort to 85.5% in the eculizumab-treated cohort (hazard ratio, 4.95; 95% confidence interval [CI], 2.75-8.90; P = .000; number needed to treat, 2.17 [95% CI, 1.81-2.73]). The outcome of eculizumab treatment is associated with the underlying genotype. Lower serum creatinine, lower platelet count, lower blood pressure, and younger age at presentation as well as shorter time between presentation and the first dose of eculizumab were associated with estimated glomerular filtration rate >60 ml/min at 6 months in multivariate analysis. The rate of meningococcal infection in the treated cohort was 550 times greater than the background rate in the general population. The relapse rate upon eculizumab withdrawal was 1 per 9.5 person years for patients with a pathogenic mutation and 1 per 10.8 person years for those with a variant of uncertain significance. No relapses were recorded in 67.3 person years off eculizumab in those with no rare genetic variants. Eculizumab was restarted in 6 individuals with functioning kidneys in whom it had been stopped, with no individual progressing to ESKD. We demonstrated that biallelic pathogenic mutations in RNA-processing genes, including EXOSC3, encoding an essential part of the RNA exosome, cause eculizumab nonresponsive aHUS. Recessive HSD11B2 mutations causing apparent mineralocorticoid excess may also present with thrombotic microangiopathy.
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Affiliation(s)
- Vicky Brocklebank
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Patrick R. Walsh
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Kate Smith-Jackson
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Thomas M. Hallam
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Kevin J. Marchbank
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Valerie Wilson
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Theophile Bigirumurame
- Population Health Sciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Tina Dutt
- Department of Haematology, Royal Liverpool University Hospital, Liverpool, United Kingdom
| | - Emma K. Montgomery
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Michal Malina
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- Great North Children's Hospital, Sir James Spence Institute, Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Edwin K. S. Wong
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Sally Johnson
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
- Great North Children's Hospital, Sir James Spence Institute, Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Neil S. Sheerin
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David Kavanagh
- National Renal Complement Therapeutics Centre, Newcastle upon Tyne Hospitals National Health Service Foundation Trust, Newcastle upon Tyne, United Kingdom
- Complement Therapeutics Research Group, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- National Institute for Health and Care Research Newcastle Biomedical Research Centre, Biomedical Research Building, Campus for Ageing and Vitality, Newcastle upon Tyne, United Kingdom
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Timmermans SA, van Doorn DP, van Paassen P. Rare Variants in Complement Genes May Not Be That Rare After All. Kidney Int Rep 2023; 8:1911-1913. [PMID: 37850005 PMCID: PMC10577486 DOI: 10.1016/j.ekir.2023.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Accepted: 08/14/2023] [Indexed: 10/19/2023] Open
Affiliation(s)
- Sjoerd A.M.E.G. Timmermans
- Department of Nephrology and Clinical Immunology, Maastricht University Medical Center, Maastricht, Netherlands
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht, Netherlands
| | - Daan P.C. van Doorn
- Department of Nephrology and Clinical Immunology, Maastricht University Medical Center, Maastricht, Netherlands
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht, Netherlands
| | - Pieter van Paassen
- Department of Nephrology and Clinical Immunology, Maastricht University Medical Center, Maastricht, Netherlands
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht, Netherlands
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Huerta A, Arjona E, Portoles J, Lopez-Sanchez P, Cavero T, Fernandez-Cusicanqui J, Blasco M, Cabello V, Calvo N, Diaz M, Herrero-Goñi M, Aguirre M, Elías S, Alcaide MP, Ramos N, Sellares J, Rodríguez de Córdoba S. On the relevance of thrombomodulin variants in atypical hemolytic uremic syndrome. Kidney Int 2023; 104:851-855. [PMID: 37567446 DOI: 10.1016/j.kint.2023.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 07/10/2023] [Accepted: 07/14/2023] [Indexed: 08/13/2023]
Affiliation(s)
- Ana Huerta
- Nephrology Department. Hospital Puerta de Hierro-Majadahonda.IDIPHISA, Madrid, Spain; RedinRen Instituto de Salud Carlos III 16/009/009, Madrid, Spain.
| | - Emi Arjona
- Centro de Investigaciones Biológicas-Margarita Salas (CIB-MS), Madrid, Spain; Ciber de Enfermedades Raras (Ciberer), Madrid, Spain
| | - Jose Portoles
- Nephrology Department. Hospital Puerta de Hierro-Majadahonda.IDIPHISA, Madrid, Spain; RedinRen Instituto de Salud Carlos III 16/009/009, Madrid, Spain
| | - Paula Lopez-Sanchez
- Nephrology Department. Hospital Puerta de Hierro-Majadahonda.IDIPHISA, Madrid, Spain
| | - Teresa Cavero
- Nephrology Department, Hospital Universitario Doce de Octubre, Madrid, Spain
| | | | - Miquel Blasco
- Nephrology Department, Hospital Clinic, Barcelona, Spain
| | - Virginia Cabello
- Nephrology Department, Hospital Virgen del Rocio, Sevilla, Spain
| | | | | | | | - Mireia Aguirre
- Pediatric Nephrology Department, Hospital Cruces, Bizkaia, Spain
| | - Sandra Elías
- Nephrology Department, Hospital Ramon y Cajal, Madrid, Spain
| | | | - Natalia Ramos
- Nephrology Department, Hospital Vall d'Hebron, Barcelona, Spain
| | - Joana Sellares
- Nephrology Department, Hospital Vall d'Hebron, Barcelona, Spain
| | - Santiago Rodríguez de Córdoba
- Centro de Investigaciones Biológicas-Margarita Salas (CIB-MS), Madrid, Spain; Ciber de Enfermedades Raras (Ciberer), Madrid, Spain.
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7
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Rydberg V, Aradottir SS, Kristoffersson AC, Svitacheva N, Karpman D. Genetic investigation of Nordic patients with complement-mediated kidney diseases. Front Immunol 2023; 14:1254759. [PMID: 37744338 PMCID: PMC10513385 DOI: 10.3389/fimmu.2023.1254759] [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: 07/07/2023] [Accepted: 08/21/2023] [Indexed: 09/26/2023] Open
Abstract
Background Complement activation in atypical hemolytic uremic syndrome (aHUS), C3 glomerulonephropathy (C3G) and immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) may be associated with rare genetic variants. Here we describe gene variants in the Swedish and Norwegian populations. Methods Patients with these diagnoses (N=141) were referred for genetic screening. Sanger or next-generation sequencing were performed to identify genetic variants in 16 genes associated with these conditions. Nonsynonymous genetic variants are described when they have a minor allele frequency of <1% or were previously reported as being disease-associated. Results In patients with aHUS (n=94, one also had IC-MPGN) 68 different genetic variants or deletions were identified in 60 patients, of which 18 were novel. Thirty-two patients had more than one genetic variant. In patients with C3G (n=40) 29 genetic variants, deletions or duplications were identified in 15 patients, of which 9 were novel. Eight patients had more than one variant. In patients with IC-MPGN (n=7) five genetic variants were identified in five patients. Factor H variants were the most frequent in aHUS and C3 variants in C3G. Seventeen variants occurred in more than one condition. Conclusion Genetic screening of patients with aHUS, C3G and IC-MPGN is of paramount importance for diagnostics and treatment. In this study, we describe genetic assessment of Nordic patients in which 26 novel variants were found.
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Affiliation(s)
| | | | | | | | - Diana Karpman
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
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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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9
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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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Aigner C, Gaggl M, Schmidt S, Kain R, Kozakowski N, Oszwald A, Prohászka Z, Sunder-Plassmann R, Schmidt A, Sunder-Plassmann G. Complement-Mediated Thrombotic Microangiopathy Related to COVID-19 or SARS-CoV-2 Vaccination. Kidney Int Rep 2023:S2468-0249(23)01305-0. [PMID: 37360817 PMCID: PMC10201914 DOI: 10.1016/j.ekir.2023.05.010] [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: 02/13/2023] [Revised: 05/09/2023] [Accepted: 05/15/2023] [Indexed: 06/28/2023] Open
Abstract
Introduction Infectious diseases and vaccinations are trigger factors for thrombotic microangiopathy. Consequently, the COVID-19 pandemic could have an effect on disease manifestation or relapse in patients with atypical hemolytic syndrome/complement-mediated thrombotic microangiopathy (aHUS/cTMA). Methods We employed the Vienna TMA cohort database to examine the incidence of COVID-19 related and of SARS-CoV-2 vaccination-related relapse of aHUS/cTMA among patients previously diagnosed with aHUS/cTMA during the first 2.5 years of the COVID-19 pandemic. We calculated incidence rates, including respective confidence intervals (CIs) and used Cox proportional hazard models for comparison of aHUS/cTMA episodes following infection or vaccination. Results Among 27 patients with aHUS/cTMA, 13 infections triggered 3 (23%) TMA episodes, whereas 70 vaccinations triggered 1 TMA episode (1%; odds ratio 0.04; 95% CI 0.003-0.37, P = 0.01). In total, the incidence of TMA after COVID-19 or SARS-CoV-2 vaccination was 6 cases per 100 patient years (95% CI 0.017-0.164) (4.5/100 patient years for COVID-19 and 1.5/100 patient years for SARS-CoV-2 vaccination). The mean follow-up time was 2.31 ± 0.26 years (total amount: 22,118 days; 62.5 years) to either the end of the follow-up or TMA relapse (outcome). Between 2012 and 2022 we did not find a significant increase in the incidence of aHUS/cTMA. Conclusion COVID-19 is associated with a higher risk for aHUS/cTMA recurrence when compared to SARS-CoV-2 vaccination. Overall, the incidence of aHUS/cTMA after COVID-19 infection or SARS-CoV-2 vaccination is low and comparable to that described in the literature.
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Affiliation(s)
- Christof Aigner
- 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
| | - Sophie Schmidt
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Renate Kain
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | | | - André Oszwald
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - Zoltán Prohászka
- Research Laboratory, Department of Internal Medicine and Hematology, and Research Group for Immunology and Hematology, Semmelweis University- EötvösLoránd Research Network (Office for Supported Research Groups), Budapest, Hungary
| | - Raute Sunder-Plassmann
- Genetics Laboratory, Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| | - Alice Schmidt
- 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
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11
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Moscvin M, Liacos CI, Chen T, Theodorakakou F, Fotiou D, Hossain S, Rowell S, Leblebjian H, Regan E, Czarnecki P, Bagnoli F, Bolli N, Richardson P, Rennke HG, Dimopoulos MA, Kastritis E, Bianchi G. Mutations in the alternative complement pathway in multiple myeloma patients with carfilzomib-induced thrombotic microangiopathy. Blood Cancer J 2023; 13:31. [PMID: 36849497 PMCID: PMC9971259 DOI: 10.1038/s41408-023-00802-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 02/09/2023] [Accepted: 02/15/2023] [Indexed: 02/28/2023] Open
Abstract
Thrombotic microangiopathy (TMA) has been reported to occur in multiple myeloma (MM) patients in association with treatment with carfilzomib, an irreversible proteasome inhibitor (PI). The hallmark of TMA is vascular endothelial damage leading to microangiopathic hemolytic anemia, platelet consumption, fibrin deposition and small-vessel thrombosis with resultant tissue ischemia. The molecular mechanisms underlying carfilzomib-associated TMA are not known. Germline mutations in the complement alternative pathway have been recently shown to portend increased risk for the development of atypical hemolytic uremic syndrome (aHUS) and TMA in the setting of allogeneic stem cell transplant in pediatric patients. We hypothesized that germline mutations in the complement alternative pathway may similarly predispose MM patients to carfilzomib-associated TMA. We identified 10 MM patients with a clinical diagnosis of TMA in the context of carfilzomib treatment and assessed for the presence of germline mutations in the complement alternative pathway. Ten, matched MM patients exposed to carfilzomib but without clinical TMA were used as negative controls. We identified a frequency of deletions in the complement Factor H genes 3 and 1 (delCFHR3-CFHR1) and genes 1 and 4 (delCFHR1-CFHR4) in MM patients with carfilzomib-associated TMA that was higher as compared to the general population and matched controls. Our data suggest that complement alternative pathway dysregulation may confer susceptibility to vascular endothelial injury in MM patients and predispose to development of carfilzomib-associated TMA. Larger, retrospective studies are needed to evaluate whether screening for complement mutations may be indicated to properly counsel patients about TMA risk with carfilzomib use.
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Affiliation(s)
- Maria Moscvin
- Amyloidosis Program, Division of Hematology, Brigham and Women's Hospital, Boston, MA, USA
- Stanford Health Care, Stanford, CA, USA
| | - Christine Ivy Liacos
- Department of Clinical Therapeutics, National Kapodistrian University of Athens, Athens, Greece
| | - Tianzeng Chen
- Amyloidosis Program, Division of Hematology, Brigham and Women's Hospital, Boston, MA, USA
| | - Foteini Theodorakakou
- Department of Clinical Therapeutics, National Kapodistrian University of Athens, Athens, Greece
| | - Despina Fotiou
- Department of Clinical Therapeutics, National Kapodistrian University of Athens, Athens, Greece
| | - Shahrier Hossain
- Department of Clinical Therapeutics, National Kapodistrian University of Athens, Athens, Greece
| | - Sean Rowell
- Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Houry Leblebjian
- Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Eileen Regan
- Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Peter Czarnecki
- Renal Division, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Filippo Bagnoli
- Department of Oncology and Onco-Hematology, University of Milan, Milan, Italy
- Hematology Division, Fondazione IRCCS Ca' Grande Ospedale Maggiore Policlinico, Milan, Italy
| | - Niccolo' Bolli
- Department of Oncology and Onco-Hematology, University of Milan, Milan, Italy
- Hematology Division, Fondazione IRCCS Ca' Grande Ospedale Maggiore Policlinico, Milan, Italy
| | - Paul Richardson
- Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Helmut G Rennke
- Amyloidosis Program, Division of Hematology, Brigham and Women's Hospital, Boston, MA, USA
| | - Meletios A Dimopoulos
- Department of Clinical Therapeutics, National Kapodistrian University of Athens, Athens, Greece
| | - Efstathios Kastritis
- Department of Clinical Therapeutics, National Kapodistrian University of Athens, Athens, Greece
| | - Giada Bianchi
- Amyloidosis Program, Division of Hematology, Brigham and Women's Hospital, Boston, MA, USA.
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12
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Abstract
Uncontrolled alternative pathway activation is the primary driver of several diseases, and it contributes to the pathogenesis of many others. Consequently, diagnostic tests to monitor this arm of the complement system are increasingly important. Defects in alternative pathway regulation are strong risk factors for disease, and drugs that specifically block the alternative pathway are entering clinical use. A range of diagnostic tests have been developed to evaluate and monitor the alternative pathway, including assays to measure its function, expression of alternative pathway constituents, and activation fragments. Genetic studies have also revealed many disease-associated variants in alternative pathway genes that predict the risk of disease and prognosis. Newer imaging modalities offer the promise of non-invasively detecting and localizing pathologic complement activation. Together, these various tests help in the diagnosis of disease, provide important prognostic information, and can help guide therapy with complement inhibitory drugs.
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Affiliation(s)
- Joshua M. Thurman
- Department of Medicine, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, USA
| | - Veronique Fremeaux-Bacchi
- Assistance Publique-Hôpitaux de Paris, European Hospital Georges Pompidou, Department of Immunology Biology and INSERM UMRS1138, Centre de Recherche des Cordeliers, Team "Inflammation, Complement and Cancer", Paris, France
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13
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Zhang Y, Goodfellow RX, Ghiringhelli Borsa N, Dunlop HC, Presti SA, Meyer NC, Shao D, Roberts SM, Jones MB, Pitcher GR, Taylor AO, Nester CM, Smith RJH. Complement Factor I Variants in Complement-Mediated Renal Diseases. Front Immunol 2022; 13:866330. [PMID: 35619721 PMCID: PMC9127439 DOI: 10.3389/fimmu.2022.866330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/08/2022] [Indexed: 11/26/2022] Open
Abstract
C3 glomerulopathy (C3G) and atypical hemolytic uremic syndrome (aHUS) are two rare diseases caused by dysregulated activity of the alternative pathway of complement secondary to the presence of genetic and/or acquired factors. Complement factor I (FI) is a serine protease that downregulates complement activity in the fluid phase and/or on cell surfaces in conjunction with one of its cofactors, factor H (FH), complement receptor 1 (CR1/CD35), C4 binding protein (C4BP) or membrane cofactor protein (MCP/CD46). Because altered FI activity is causally related to the pathogenesis of C3G and aHUS, we sought to test functional activity of select CFI missense variants in these two patient cohorts. We identified 65 patients (16, C3G; 48, aHUS; 1 with both) with at least one rare variant in CFI (defined as a MAF < 0.1%). Eight C3G and eleven aHUS patients also carried rare variants in either another complement gene, ADAMTS13 or THBD. We performed comprehensive complement analyses including biomarker profiling, pathway activity and autoantibody testing, and developed a novel FI functional assay, which we completed on 40 patients. Seventy-eight percent of rare CFI variants (31/40) were associated with FI protein levels below the 25th percentile; in 22 cases, FI levels were below the lower limit of normal (type 1 variants). Of the remaining nine variants, which associated with normal FI levels, two variants reduced FI activity (type 2 variants). No patients carried currently known autoantibodies (including FH autoantibodies and nephritic factors). We noted that while rare variants in CFI predispose to complement-mediated diseases, phenotypes are strongly contingent on the associated genetic background. As a general rule, in isolation, a rare CFI variant most frequently leads to aHUS, with the co-inheritance of a CD46 loss-of-function variant driving the onset of aHUS to the younger age group. In comparison, co-inheritance of a gain-of-function variant in C3 alters the phenotype to C3G. Defects in CFH (variants or fusion genes) are seen with both C3G and aHUS. This variability underscores the complexity and multifactorial nature of these two complement-mediated renal diseases.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Richard J. H. Smith
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA, United States
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14
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Hanna RM, Henriksen K, Kalantar-Zadeh K, Ferrey A, Burwick R, Jhaveri KD. Thrombotic Microangiopathy Syndromes-Common Ground and Distinct Frontiers. Adv Chronic Kidney Dis 2022; 29:149-160.e1. [PMID: 35817522 DOI: 10.1053/j.ackd.2021.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 11/02/2021] [Accepted: 11/18/2021] [Indexed: 11/11/2022]
Abstract
Thrombotic microangiopathies (TMAs) have in common a terminal phenotype of microangiopathic hemolytic anemia with end-organ dysfunction. Thrombotic thrombocytopenic purpura results from von Willebrand factor multimerization, Shiga toxin-mediated hemolytic uremic syndrome causes toxin-induced endothelial dysfunction, while atypical hemolytic uremic syndrome results from complement system dysregulation. Drug-induced TMA, rheumatological disease-induced TMA, and renal-limited TMA exist in an intermediate space that represents secondary complement activation and may overlap with atypical hemolytic uremic syndrome clinically. The existence of TMA without microangiopathic hemolytic features, renal-limited TMA, represents an undiscovered syndrome that responds incompletely and inconsistently to complement blockade. Hematopoietic stem cell transplant-TMA represents another more resistant form of TMA with different therapeutic needs and clinical course. It has become apparent that TMA syndromes are an emerging field in nephrology, rheumatology, and hematology. Much work remains in genetics, molecular biology, and therapeutics to unravel the puzzle of the relationships and distinctions apparent between the different subclasses of TMA syndromes.
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Affiliation(s)
- Ramy M Hanna
- UCI Medical Center Department of Medicine, Division of Nephrology, University of California Irvine, Orange, CA.
| | - Kammi Henriksen
- Department of Pathology, University of Chicago Medical Center, Chicago, IL
| | - Kamyar Kalantar-Zadeh
- UCI Medical Center Department of Medicine, Division of Nephrology, University of California Irvine, Orange, CA
| | - Antoney Ferrey
- UCI Medical Center Department of Medicine, Division of Nephrology, University of California Irvine, Orange, CA
| | - Richard Burwick
- Department of Obstetrics and Gynecology, Maternal-Fetal Medicine, Cedars Sinai Medical Center, Los Angeles, CA
| | - Kenar D Jhaveri
- Glomerular Disease Center at Northwell Health, Division of Kidney Diseases and Hypertension, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Great Neck, NY
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15
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Freiwald T, Afzali B. Renal diseases and the role of complement: Linking complement to immune effector pathways and therapeutics. Adv Immunol 2021; 152:1-81. [PMID: 34844708 PMCID: PMC8905641 DOI: 10.1016/bs.ai.2021.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The complement system is an ancient and phylogenetically conserved key danger sensing system that is critical for host defense against pathogens. Activation of the complement system is a vital component of innate immunity required for the detection and removal of pathogens. It is also a central orchestrator of adaptive immune responses and a constituent of normal tissue homeostasis. Once complement activation occurs, this system deposits indiscriminately on any cell surface in the vicinity and has the potential to cause unwanted and excessive tissue injury. Deposition of complement components is recognized as a hallmark of a variety of kidney diseases, where it is indeed associated with damage to the self. The provenance and the pathophysiological role(s) played by complement in each kidney disease is not fully understood. However, in recent years there has been a renaissance in the study of complement, with greater appreciation of its intracellular roles as a cell-intrinsic system and its interplay with immune effector pathways. This has been paired with a profusion of novel therapeutic agents antagonizing complement components, including approved inhibitors against complement components (C)1, C3, C5 and C5aR1. A number of clinical trials have investigated the use of these more targeted approaches for the management of kidney diseases. In this review we present and summarize the evidence for the roles of complement in kidney diseases and discuss the available clinical evidence for complement inhibition.
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Affiliation(s)
- Tilo Freiwald
- Immunoregulation Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Bethesda, MD, United States; Department of Nephrology, University Hospital Frankfurt, Goethe-University, Frankfurt am Main, Germany
| | - Behdad Afzali
- Department of Nephrology, University Hospital Frankfurt, Goethe-University, Frankfurt am Main, Germany.
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16
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Fakhouri F, Frémeaux-Bacchi V. Thrombotic microangiopathy in aHUS and beyond: clinical clues from complement genetics. Nat Rev Nephrol 2021; 17:543-553. [PMID: 33953366 DOI: 10.1038/s41581-021-00424-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2021] [Indexed: 02/02/2023]
Abstract
Studies of complement genetics have changed the landscape of thrombotic microangiopathies (TMAs), particularly atypical haemolytic uraemic syndrome (aHUS). Knowledge of complement genetics paved the way for the design of the first specific treatment for aHUS, eculizumab, and is increasingly being used to aid decisions regarding discontinuation of anti-complement treatment in this setting. Complement genetic studies have also been used to investigate the pathogenic mechanisms that underlie other forms of HUS and provided evidence that contributed to the reclassification of pregnancy- and postpartum-associated HUS within the spectrum of complement-mediated aHUS. By contrast, complement genetics has not provided definite evidence of a link between constitutional complement dysregulation and secondary forms of HUS. Therefore, the available data do not support systematic testing of complement genes in patients with typical HUS or secondary HUS. The potential relevance of complement genetics for distinguishing the underlying mechanisms of malignant hypertension-associated TMA should be assessed with caution owing to the overlap between aHUS and other causes of malignant hypertension. In all cases, the interpretation of complement genetics results remains complex, as even complement-mediated aHUS is not a classical monogenic disease. Such interpretation requires the input of trained geneticists and experts who have a comprehensive view of complement biology.
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Affiliation(s)
- Fadi Fakhouri
- Service of Nephrology and Hypertension, Department of Medicine, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
| | - Véronique Frémeaux-Bacchi
- Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Service d'Immunologie, Paris, France
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17
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The Syndromes of Thrombotic Microangiopathy: A Critical Appraisal on Complement Dysregulation. J Clin Med 2021; 10:jcm10143034. [PMID: 34300201 PMCID: PMC8307963 DOI: 10.3390/jcm10143034] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 01/12/2023] Open
Abstract
Thrombotic microangiopathy (TMA) is a rare and potentially life-threatening condition that can be caused by a heterogeneous group of diseases, often affecting the brain and kidneys. TMAs should be classified according to etiology to indicate targets for treatment. Complement dysregulation is an important cause of TMA that defines cases not related to coexisting conditions, that is, primary atypical hemolytic uremic syndrome (HUS). Ever since the approval of therapeutic complement inhibition, the approach of TMA has focused on the recognition of primary atypical HUS. Recent advances, however, demonstrated the pivotal role of complement dysregulation in specific subtypes of patients considered to have secondary atypical HUS. This is particularly the case in patients presenting with coexisting hypertensive emergency, pregnancy, and kidney transplantation, shifting the paradigm of disease. In contrast, complement dysregulation is uncommon in patients with other coexisting conditions, such as bacterial infection, drug use, cancer, and autoimmunity, among other disorders. In this review, we performed a critical appraisal on complement dysregulation and the use of therapeutic complement inhibition in TMAs associated with coexisting conditions and outline a pragmatic approach to diagnosis and treatment. For future studies, we advocate the term complement-mediated TMA as opposed to the traditional atypical HUS-type classification.
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18
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Willrich MAV, Braun KMP, Moyer AM, Jeffrey DH, Frazer-Abel A. Complement testing in the clinical laboratory. Crit Rev Clin Lab Sci 2021; 58:447-478. [PMID: 33962553 DOI: 10.1080/10408363.2021.1907297] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The complement system is the human's first line of defense against microbial pathogens because of its important housekeeping and infection/inflammation roles. It is composed of a series of soluble and cell-bound proteins that are activated in a cascade effect, similar to the coagulation pathways. There are different pattern recognizing molecules that activate the complement system in response to stimuli or threats, acting through three initiation pathways: classical, lectin, and alternative. All three activation pathways converge at the C3 component and share the terminal pathway. The main outputs of the complement system action are lytic killing of microbes, the release of pro-inflammatory anaphylatoxins, and opsonization of targets. Laboratory testing is relevant in the setting of suspected complement deficiencies, as well as in the emerging number of diseases related to dysregulation (over-activation) of complement. Most common assays measure complement lytic activity and the different complement component concentrations. Specialized testing includes the evaluation of autoantibodies against complement components, activation fragments, and genetic studies. In this review, we cover laboratory testing for complement and the conditions with complement involvement, as well as current challenges in the field.
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Affiliation(s)
| | - Karin M P Braun
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Ann M Moyer
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - David H Jeffrey
- Exsera Biolabs, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ashley Frazer-Abel
- Exsera Biolabs, Department of Medicine, University of Colorado School of Medicine, Aurora, CO, USA
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19
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Eculizumab discontinuation in children and adults with atypical hemolytic-uremic syndrome: a prospective multicenter study. Blood 2021; 137:2438-2449. [PMID: 33270832 DOI: 10.1182/blood.2020009280] [Citation(s) in RCA: 88] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 11/23/2020] [Indexed: 12/21/2022] Open
Abstract
The optimal duration of eculizumab treatment in patients with atypical hemolytic uremic syndrome (aHUS) remains poorly defined. We conducted a prospective national multicenter open-label study to assess eculizumab discontinuation in children and adults with aHUS. Fifty-five patients (including 19 children) discontinued eculizumab (mean treatment duration, 16.5 months). Twenty-eight patients (51%) had rare variants in complement genes, mostly in MCP (n = 12; 22%), CFH (n = 6; 11%), and CFI (n = 6; 10%). At eculizumab discontinuation, 17 (30%) and 4 patients (7%) had stage 3 and 4 chronic kidney disease, respectively. During follow-up, 13 patients (23%; 6 children and 7 adults) experienced aHUS relapse. In multivariable analysis, female sex and presence of a rare variant in a complement gene were associated with an increased risk of aHUS relapse, whereas requirement for dialysis during a previous episode of acute aHUS was not. In addition, increased sC5b-9 plasma level at eculizumab discontinuation was associated with a higher risk of aHUS relapse in all patients and in the subset of carriers with a complement gene rare variant, both by log-rank test and in multivariable analysis. Of the 13 relapsing patients, all of whom restarted eculizumab, 11 regained their baseline renal function and 2 had a worsening of their preexisting chronic kidney disease, including 1 patient who progressed to end-stage renal disease. A strategy of eculizumab discontinuation in aHUS patients based on complement genetics is reasonable and safe. It improves the management and quality of life of a sizeable proportion of aHUS patients while reducing the cost of treatment. This trial was registered at www.clinicaltrials.gov as #NCT02574403.
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20
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Furmańczyk-Zawiska A, Kubiak-Dydo A, Użarowska-Gąska E, Kotlarek-Łysakowska M, Salata K, Kolanowska M, Świerniak M, Gaj P, Leszczyńska B, Daniel M, Jażdżewski K, Durlik M, Wójcicka A. Compound Haplotype Variants in CFH and CD46 Genes Determine Clinical Outcome of Atypical Hemolytic Uremic Syndrome (aHUS)-A Series of Cases from a Single Family. J Pers Med 2021; 11:jpm11040304. [PMID: 33920896 PMCID: PMC8071215 DOI: 10.3390/jpm11040304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/11/2021] [Accepted: 04/12/2021] [Indexed: 11/16/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare disease triggered by dysregulation of the alternative complement pathway, consisting of a characteristic triad of nonimmune hemolytic anemia, thrombocytopenia, and renal failure. The risk of aHUS onset, recurrence, and allograft loss depends on the genetic background of a patient. We show a series of cases from a single family whose five members were affected by aHUS and presented distinct clinical outcomes. Next-generation sequencing revealed combined mutations in both complement factor H and membrane cofactor protein CD46. Out of eight siblings, aHUS affected three adult brothers, and, subsequently, affected two children of an unaffected sister. The first patient died due to aHUS, and two other brothers underwent successful kidney transplantation with no aHUS recurrence. The younger, 10-month-old child presented with a severe course of the disease with cardiac involvement and persistent hemolytic anemia limited by eculizumab, while the 2-year-old recovered completely on eculizumab. The study shows a highly variable disease penetrance.
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Affiliation(s)
- Agnieszka Furmańczyk-Zawiska
- Department of Transplantation Medicine, Nephrology and Internal Diseases, Medical University of Warsaw, 02-006 Warsaw, Poland; (A.F.-Z.); (M.D.)
| | - Anna Kubiak-Dydo
- Warsaw Genomics INC, 01-682 Warsaw, Poland; (A.K.-D.); (E.U.-G.); (M.K.-Ł.); (K.S.); (M.K.); (M.Ś.); (P.G.); (K.J.)
| | - Ewelina Użarowska-Gąska
- Warsaw Genomics INC, 01-682 Warsaw, Poland; (A.K.-D.); (E.U.-G.); (M.K.-Ł.); (K.S.); (M.K.); (M.Ś.); (P.G.); (K.J.)
- Postgraduate School of Molecular Medicine, Medical University of Warsaw, 02-091 Warsaw, Poland
| | - Marta Kotlarek-Łysakowska
- Warsaw Genomics INC, 01-682 Warsaw, Poland; (A.K.-D.); (E.U.-G.); (M.K.-Ł.); (K.S.); (M.K.); (M.Ś.); (P.G.); (K.J.)
| | - Katarzyna Salata
- Warsaw Genomics INC, 01-682 Warsaw, Poland; (A.K.-D.); (E.U.-G.); (M.K.-Ł.); (K.S.); (M.K.); (M.Ś.); (P.G.); (K.J.)
| | - Monika Kolanowska
- Warsaw Genomics INC, 01-682 Warsaw, Poland; (A.K.-D.); (E.U.-G.); (M.K.-Ł.); (K.S.); (M.K.); (M.Ś.); (P.G.); (K.J.)
| | - Michał Świerniak
- Warsaw Genomics INC, 01-682 Warsaw, Poland; (A.K.-D.); (E.U.-G.); (M.K.-Ł.); (K.S.); (M.K.); (M.Ś.); (P.G.); (K.J.)
| | - Paweł Gaj
- Warsaw Genomics INC, 01-682 Warsaw, Poland; (A.K.-D.); (E.U.-G.); (M.K.-Ł.); (K.S.); (M.K.); (M.Ś.); (P.G.); (K.J.)
| | - Beata Leszczyńska
- Department of Pediatrics Nephrology, Medical University of Warsaw, 02-091 Warsaw, Poland; (B.L.); (M.D.)
| | - Maria Daniel
- Department of Pediatrics Nephrology, Medical University of Warsaw, 02-091 Warsaw, Poland; (B.L.); (M.D.)
| | - Krystian Jażdżewski
- Warsaw Genomics INC, 01-682 Warsaw, Poland; (A.K.-D.); (E.U.-G.); (M.K.-Ł.); (K.S.); (M.K.); (M.Ś.); (P.G.); (K.J.)
- Laboratory of Human Cancer Genetics, University of Warsaw, 02-089 Warsaw, Poland
| | - Magdalena Durlik
- Department of Transplantation Medicine, Nephrology and Internal Diseases, Medical University of Warsaw, 02-006 Warsaw, Poland; (A.F.-Z.); (M.D.)
| | - Anna Wójcicka
- Warsaw Genomics INC, 01-682 Warsaw, Poland; (A.K.-D.); (E.U.-G.); (M.K.-Ł.); (K.S.); (M.K.); (M.Ś.); (P.G.); (K.J.)
- Correspondence:
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21
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Pregnancy-triggered atypical hemolytic uremic syndrome (aHUS): a Global aHUS Registry analysis. J Nephrol 2021; 34:1581-1590. [PMID: 33826112 PMCID: PMC8494679 DOI: 10.1007/s40620-021-01025-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/10/2021] [Indexed: 11/09/2022]
Abstract
Background Atypical hemolytic uremic syndrome (aHUS) is a rare disease in which uncontrolled terminal complement activation leads to systemic thrombotic microangiopathy (TMA). Pregnancy can trigger aHUS and, without complement inhibition, many women with pregnancy-triggered aHUS (p-aHUS) progress to end-stage renal disease (ESRD) with a high risk of morbidity. Owing to relatively small patient numbers, published characterizations of p-aHUS have been limited, thus the Global aHUS Registry (NCT01522183, April 2012) provides a unique opportunity to analyze data from a large single cohort of women with p-aHUS. Methods The demographics and clinical characteristics of women with p-aHUS (n = 51) were compared with those of women of childbearing age with aHUS and no identified trigger (non-p-aHUS, n = 397). Outcome evaluations, including renal survival according to time to ESRD, were compared for patients with and without eculizumab treatment (a complement C5 inhibitor) in both aHUS groups. Results Baseline demographics and clinical characteristics were broadly similar in both groups. The proportion of women with p-aHUS and non-p-aHUS with pathogenic variant(s) in complement genes and/or anti-complement factor H antibodies was similar (45% and 43%, respectively), as was the proportion with a family history of aHUS (12% and 13%, respectively). Eculizumab treatment led to significantly improved renal outcomes in women with aHUS, regardless of whether aHUS was triggered by pregnancy or not: adjusted hazard ratio for time to ESRD was 0.06 (p = 0.006) in the p-aHUS group and 0.20 (p < 0.0001) in the non-p-aHUS group. Conclusion Findings from this study support the characterization of p-aHUS as a complement-mediated TMA. Graphic abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1007/s40620-021-01025-x.
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22
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Åkesson A, Martin M, Blom AM, Rossing M, Gabrielaite M, Zetterberg E, Klintman J. Clinical characterization and identification of rare genetic variants in atypical hemolytic uremic syndrome: A Swedish retrospective observational study. Ther Apher Dial 2021; 25:988-1000. [PMID: 33609329 DOI: 10.1111/1744-9987.13634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/27/2021] [Accepted: 02/18/2021] [Indexed: 11/30/2022]
Abstract
Complement-mediated atypical hemolytic uremic syndrome (aHUS) is an ultra-rare renal disease primarily caused by genetic alterations in complement proteins. The genetic work-up required for confirmation of diagnosis is complicated and not always logistically accessible. The aim of the present study was to apply a diagnostic scheme compliant with the American College of Medical Genetics and Genomics guidelines to investigate the prevalence of complement-mediated aHUS among subjects formerly included in a retrospective cohort of clinically suspected aHUS. Clinical outcomes and genetic correlations to complement analyses were assessed. Subjects were investigated with medical record reviewing, inquiries, and laboratory analyses composed of whole genome sequencing; enzyme-linked immunosorbent assays for factor I, factor H, and factor H-specific antibodies; nephelometry for complement components three of four; flow cytometry for CD46 surface expression and immunoblotting for the presence of factor H-related protein 1. In total, 45% (n = 60/134) of the subjects were deceased at the time of study. Twenty of the eligible subjects consented to study participation. Based on genetic sequencing and clinical characteristics, six were categorized as definite/highly suspected complement-mediated aHUS, 10 as non-complement-mediated aHUS and four as having an HUS-like phenotype. In the complement-mediated aHUS group, two subjects had not received an aHUS diagnosis during the routine clinical management. Disease-contributing/likely disease-contributing genetic variants were identified in five subjects, including a novel missense variant in the complement factor H gene (c.3450A>G, p.I1150M). This study illustrates the risk for misdiagnosis in the management of patients with complement-mediated aHUS and the importance of a comprehensive assessment of both phenotype and genotype to reach a diagnosis.
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Affiliation(s)
- Alexander Åkesson
- The Clinical Coagulation Research Unit, Department of Translational Medicine, Lund University, Skane University Hospital, Malmo, Sweden
| | - Myriam Martin
- The Medical Protein Chemistry Research Group, Department of Translational Medicine, Lund University, Malmo, Sweden
| | - Anna M Blom
- The Medical Protein Chemistry Research Group, Department of Translational Medicine, Lund University, Malmo, Sweden
| | - Maria Rossing
- Centre for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Migle Gabrielaite
- Centre for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Eva Zetterberg
- The Clinical Coagulation Research Unit, Department of Translational Medicine, Lund University, Skane University Hospital, Malmo, Sweden
| | - Jenny Klintman
- The Clinical Coagulation Research Unit, Department of Translational Medicine, Lund University, Skane University Hospital, Malmo, Sweden
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23
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Enjeti AK, de Malmanche T, Chapman K, Ziolkowski A. Genomic investigation of inherited thrombotic microangiopathy-aHUS and TTP. Int J Lab Hematol 2021; 42 Suppl 1:33-40. [PMID: 32543063 DOI: 10.1111/ijlh.13201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/16/2020] [Accepted: 03/19/2020] [Indexed: 12/12/2022]
Abstract
Thrombotic microangiopathies (TMA) are a heterogeneous group of red cell fragmentation syndromes characterized by a tendency for thrombosis and pathognomonic red cell fragments in peripheral blood, which results in thrombosis in the microvasculature due to endothelial damage. Genomic investigations into inherited TMAs are of diagnostic, prognostic and therapeutic value. Here, we present two cases that capture the importance of performing genomic testing in rare disorders. Treatment options for these conditions, such as plasma exchange and monoclonal antibodies against complement factors, are intensive and expensive health care interventions. The results of genomic investigation into rare TMAs can better inform the clinicians and their patients of prognosis and suitable personalized treatment options.
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Affiliation(s)
- Anoop K Enjeti
- NSW Health Pathology North, John Hunter Campus, New Lambton Heights, NSW, Australia.,Calvary Mater Newcastle, Waratah, NSW, Australia.,School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, Australia.,Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
| | - Theo de Malmanche
- NSW Health Pathology North, John Hunter Campus, New Lambton Heights, NSW, Australia.,School of Medicine and Public Health, University of Newcastle, Callaghan, NSW, Australia
| | - Kent Chapman
- NSW Health Pathology North, John Hunter Campus, New Lambton Heights, NSW, Australia
| | - Andrew Ziolkowski
- NSW Health Pathology North, John Hunter Campus, New Lambton Heights, NSW, Australia.,Hunter Medical Research Institute, New Lambton Heights, NSW, Australia
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24
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Zhang Y, Ghiringhelli Borsa N, Shao D, Dopler A, Jones MB, Meyer NC, Pitcher GR, Taylor AO, Nester CM, Schmidt CQ, Smith RJH. Factor H Autoantibodies and Complement-Mediated Diseases. Front Immunol 2020; 11:607211. [PMID: 33384694 PMCID: PMC7770156 DOI: 10.3389/fimmu.2020.607211] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/05/2020] [Indexed: 12/25/2022] Open
Abstract
Factor H (FH), a member of the regulators-of-complement-activation (RCA) family of proteins, circulates in human plasma at concentrations of 180–420 mg/L where it controls the alternative pathway (AP) of complement in the fluid phase and on cell surfaces. When the regulatory function of FH is impaired, complement-mediated tissue injury and inflammation occur, leading to diseases such as atypical hemolytic uremic syndrome (a thrombotic microangiopathy or TMA), C3 glomerulopathy (C3G) and monoclonal gammopathy of renal significance (MGRS). A pathophysiological cause of compromised FH function is the development of autoantibodies to various domains of the FH protein. FH autoantibodies (FHAAs) are identified in 10.9% of patients with aHUS, 3.2% of patients with C3G, and rarely in patients with MGRS. The phenotypic variability of FHAA-mediated disease reflects both the complexity of FH and the epitope specificity of FHAA for select regions of the native protein. In this paper, we have characterized FHAA epitopes in a large cohort of patients diagnosed with TMA, C3G or MGRS. We explore the epitopes recognized by FHAAs in these diseases and the association of FHAAs with the genetic deletion of both copies of the CFHR1 gene to show how these disease phenotypes are associated with this diverse spectrum of autoantibodies.
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Affiliation(s)
- Yuzhou Zhang
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA, United States
| | - Nicolo Ghiringhelli Borsa
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA, United States
| | - Dingwu Shao
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA, United States
| | - Arthur Dopler
- Institute of Pharmacology of Natural Products & Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Michael B Jones
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA, United States
| | - Nicole C Meyer
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA, United States
| | - Gabriella R Pitcher
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA, United States
| | - Amanda O Taylor
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA, United States
| | - Carla M Nester
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA, United States
| | - Christoph Q Schmidt
- Institute of Pharmacology of Natural Products & Clinical Pharmacology, Ulm University, Ulm, Germany
| | - Richard J H Smith
- Molecular Otolaryngology and Renal Research Laboratories, University of Iowa, Iowa City, IA, United States
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25
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Avila Bernabeu AI, Cavero Escribano T, Cao Vilarino M. Atypical Hemolytic Uremic Syndrome: New Challenges in the Complement Blockage Era. Nephron Clin Pract 2020; 144:537-549. [PMID: 32950988 DOI: 10.1159/000508920] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/22/2020] [Indexed: 11/19/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare cause of thrombotic microangiopathy (TMA), characterized by microangiopathic hemolytic anemia, consumptive thrombocytopenia, and multisystem end organ involvement, most commonly affecting the kidney. Diagnosis is clinical, after exclusion of other TMA causes. Primary aHUS arises from genetic abnormalities, resulting in uncontrolled complement activity, while a variety of clinical scenarios cause secondary aHUS, including infection, pregnancy, malignancy, autoimmune disease, and medications. They can also induce a temporary complement deregulation with an overlap between both scenarios, which can make differential diagnosis difficult. Primary aHUS can be sporadic or familial and is associated with a high rate of progression to ESRD. Many aHUS patients relapse in the native or transplanted kidneys, leading to kidney failure. The introduction of eculizumab has changed the prognosis of aHUS, by inducing hematologic remission, improving or stabilizing kidney functions, and preventing graft failure. The early institution of appropriate therapy can prevent multiorgan damage, so is essential to recognize and differentiate the TMA syndromes. Eculizumab is considered now the first-line treatment, and it is recommended lifelong therapy. However, the high cost of therapy has led to make efforts to develop precise complement functional and genetic studies that help physicians to determine the appropriate duration of eculizumab therapy. Nowadays, more studies are needed to select candidates to adjustment of therapy.
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26
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Wilson PC, Love-Gregory L, Corliss M, McNulty S, Heusel JW, Gaut JP. Beyond Panel-Based Testing: Exome Analysis Increases Sensitivity for Diagnosis of Genetic Kidney Disease. KIDNEY360 2020; 1:772-780. [PMID: 35372954 PMCID: PMC8815744 DOI: 10.34067/kid.0001342020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 05/12/2020] [Indexed: 05/16/2023]
Abstract
BACKGROUND Next-generation sequencing (NGS) is a useful tool for evaluating patients with suspected genetic kidney disease. Clinical practice relies on the use of targeted gene panels that are ordered based on patient presentation. We compare the diagnostic yield of clinical panel-based testing to exome analysis. METHODS In total, 324 consecutive patients underwent physician-ordered, panel-based NGS testing between December 2014 and October 2018. Gene panels were available for four clinical phenotypes, including atypical hemolytic uremic syndrome (n=224), nephrotic syndrome (n=56), cystic kidney disease (n=26), and Alport syndrome (n=13). Variants were analyzed and clinical reports were signed out by a pathologist or clinical geneticist at the time of testing. Subsequently, all patients underwent retrospective exome analysis to detect additional clinically significant variants in kidney disease genes that were not analyzed as part of the initial clinical gene panel. Resulting variants were classified according to the American College of Medical Genetics and Genomics 2015 guidelines. RESULTS In the initial physician-ordered gene panels, we identified clinically significant pathogenic or likely pathogenic variants in 13% of patients (n=42/324). CFHR3-CFHR1 homozygous deletion was detected in an additional 13 patients with aHUS without a pathogenic or likely pathogenic variant. Diagnostic yield of the initial physician-ordered gene panel was 20% and varied between groups. Retrospective exome analysis identified 18 patients with a previously unknown pathogenic or likely pathogenic variant in a kidney disease gene and eight patients with a high-risk APOL1 genotype. Overall, retrospective exome analysis increased the diagnostic yield of panel-based testing from 20% to 30%. CONCLUSIONS These results highlight the importance of a broad and collaborative approach between the clinical laboratory and their physician clients that employs additional analysis when a targeted panel of kidney disease-causing genes does not return a clinically meaningful result.
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Affiliation(s)
- Parker C. Wilson
- Division of Anatomic and Molecular Pathology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Latisha Love-Gregory
- Division of Anatomic and Molecular Pathology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Meagan Corliss
- Division of Laboratory and Genomic Medicine, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Samantha McNulty
- Division of Laboratory and Genomic Medicine, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
| | - Jonathan W. Heusel
- Division of Laboratory and Genomic Medicine, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri
| | - Joseph P. Gaut
- Division of Anatomic and Molecular Pathology, Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
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27
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Besse W. Genetic Analysis in Kidney Disease: Advancing Clinical Diagnosis and Research Discovery. KIDNEY360 2020; 1:720-723. [PMID: 34327334 PMCID: PMC8317592 DOI: 10.34067/kid.0003632020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 07/09/2020] [Indexed: 11/27/2022]
Affiliation(s)
- Whitney Besse
- Department of Internal Medicine (Nephrology), Yale School of Medicine, New Haven, Connecticut
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28
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Schwarz C, Brehon A, Mousseaux C, Luque Y, Senet P, Mariani P, Mohamadou I, Zafrani L, Frémeaux-Bacchi V, Rondeau E, Buob D, Rafat C. Ockham's razor defeated: about two atypical cases of hemolytic uremic syndrome. BMC Nephrol 2020; 21:269. [PMID: 32652955 PMCID: PMC7353709 DOI: 10.1186/s12882-020-01926-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 07/02/2020] [Indexed: 12/22/2022] Open
Abstract
Background Medical investigation is a favorite application of Ockham’s razor, in virtue of which when presented with competing hypotheses, the solution with the fewest assumptions should be privileged. Hemolytic uremic syndrome (HUS) encompasses diseases with distinct pathological mechanisms, such as HUS due to shiga-like toxin-producing bacteria (STEC-HUS) and atypical HUS, linked to defects in the alternate complement pathway. Other etiologies such as Parvovirus B19 infection are exceptional. All these causes are rare to such extent that we usually consider them mutually exclusive. We report here two cases of HUS that could be traced to multiple causes. Cases presentation Case 1 presented as vomiting and diarrhea. All biological characteristics of HUS were present. STEC was found in stool (by PCR and culture). After initial remission, a recurrence occurred and patient was started on Eculizumab. Genetic analysis revealed the heterozygous presence of a CFHR1/CFH hybrid gene. The issue was favorable under treatment. In case 2, HUS presented as fever, vomiting and purpura of the lower limbs. Skin lesions and erythroblastopenia led to suspect Parvovirus B19 primo-infection, which was confirmed by peripheral blood and medullar PCR. Concurrently, stool culture and PCR revealed the presence of STEC. Evolution showed spontaneous recovery. Conclusions Both cases defy Ockham’s razor in the sense that multiple causes could be traced to a single outcome; furthermore, they invite us to reflect on the physiopathology of HUS as they question the classical distinction between STEC-HUS and atypical HUS. We propose a two-hit mechanism model leading to HUS. Indeed, in case 1, HUS unfolded as a result of the synergistic interaction between an infectious trigger and a genetic predisposition. In case 2 however, it is the simultaneous occurrence of two infectious triggers that led to HUS. In dissent from Ockham’s razor, an exceptional disease such as HUS may stem from the sequential occurrence or co-occurrence of several rare conditions.
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Affiliation(s)
- Chloe Schwarz
- Service d'urgences néphrologiques et transplantation rénale, hôpital Tenon, Paris, France.
| | - Alice Brehon
- Service de dermatologie, hôpital Tenon, Paris, France
| | - Cyril Mousseaux
- Service d'urgences néphrologiques et transplantation rénale, hôpital Tenon, Paris, France
| | - Yosu Luque
- Service d'urgences néphrologiques et transplantation rénale, hôpital Tenon, Paris, France
| | | | | | - Inna Mohamadou
- Service d'urgences néphrologiques et transplantation rénale, hôpital Tenon, Paris, France
| | - Lara Zafrani
- Service de Médecine Intensive et Réanimation, hôpital Saint Louis, Paris, France
| | | | - Eric Rondeau
- Service d'urgences néphrologiques et transplantation rénale, hôpital Tenon, Paris, France
| | - David Buob
- Service d'anatomopathologie, hôpital Tenon, Paris, France
| | - Cédric Rafat
- Service d'urgences néphrologiques et transplantation rénale, hôpital Tenon, Paris, France
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29
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Zhang Y, Kremsdorf RA, Sperati CJ, Henriksen KJ, Mori M, Goodfellow RX, Pitcher GR, Benson CL, Borsa NG, Taylor RP, Nester CM, Smith RJH. Mutation of complement factor B causing massive fluid-phase dysregulation of the alternative complement pathway can result in atypical hemolytic uremic syndrome. Kidney Int 2020; 98:1265-1274. [PMID: 32540405 DOI: 10.1016/j.kint.2020.05.028] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/25/2020] [Accepted: 05/01/2020] [Indexed: 01/05/2023]
Abstract
Atypical hemolytic uremic syndrome is an ultra-rare disease characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute kidney injury. Its pathogenesis is driven most frequently by dysregulated cell-surface control of the alternative pathway of complement secondary to inherited and/or acquired factors. Here we evaluated two unrelated patients with atypical hemolytic uremic syndrome. The first, a five-year-old Caucasian female, presented at 10 months with schistocytes, thrombocytopenia and kidney injury. The second, a 55-year-old Caucasian female, presented at age 31 following caesarean section for preeclampsia. Complement biomarker testing was remarkable for undetectable levels of C3 in both. Circulating levels of C5 and properdin were also low consistent with over-activity of the alternative and terminal pathways of complement. Genetic testing identified a heterozygous novel variant in CFB (c.1101 C>A, p.Ser367Arg) in both patients. Functional studies found strong fluid-phase C3 cleavage when normal and proband sera were mixed. Cell-surface C3b deposition was strongly positive when patient serum was supplemented with C3. In vitro control of C3 convertase activity could be restored with increased concentrations of factor H. Thus, CFB p.Ser367Arg is a gain-of-function pathogenic variant that leads to dysregulation of the alternative pathway in the fluid-phase and increased C3b deposition on cell surfaces. Our study highlights the complexities of complement-mediated diseases like atypical hemolytic uremic syndrome and illustrates the importance of functional studies at the variant level to gain insight into the disease phenotype.
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Affiliation(s)
- Yuzhou Zhang
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Robin A Kremsdorf
- Department of Pediatrics, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - C John Sperati
- Division of Nephrology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kammi J Henriksen
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Mari Mori
- Division of Genetic and Genomic Medicine, Nationwide Children's Hospital, Columbus, Ohio, USA; Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Renee X Goodfellow
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Gabriella R Pitcher
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Cindy L Benson
- Division of Human Genetics, Department of Pediatrics, Rhode Island Hospital, Providence, Rhode Island, USA
| | - Nicolo Ghiringhelli Borsa
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Ronald P Taylor
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Carla M Nester
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Richard J H Smith
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
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Abstract
The renaissance of complement diagnostics and therapeutics has introduced precision medicine into a widened field of complement-mediated diseases. In particular, complement-mediated diseases (or complementopathies) with ongoing or published clinical trials of complement inhibitors include paroxysmal nocturnal hemoglobinuria, cold agglutinin disease, hemolytic uremic syndrome, nephropathies, HELLP syndrome, transplant-associated thrombotic microangiopathy, antiphospholipid antibody syndrome, myasthenia gravis, and neuromyelitis optica. Recognizing that this field is rapidly expanding, we aim to provide a state-of-the-art review of (a) current understanding of complement biology for the clinician, (b) novel insights into complement with potential applicability to clinical practice, (c) complement in disease across various disciplines (hematology, nephrology, obstetrics, transplantation, rheumatology, and neurology), and (d) the potential future of precision medicine. Better understanding of complement diagnostics and therapeutics will not only facilitate physicians treating patients in clinical practice but also provide the basis for future research toward precision medicine in this field.
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Affiliation(s)
- Eleni Gavriilaki
- Hematology Department, G. Papanicolaou Hospital, Thessaloniki, Greece
| | - Robert A. Brodsky
- Division of Hematology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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31
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Atypical hemolytic uremic syndrome and complement blockade: established and emerging uses of complement inhibition. Curr Opin Nephrol Hypertens 2020; 28:278-287. [PMID: 30865166 DOI: 10.1097/mnh.0000000000000499] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE OF REVIEW Atypical hemolytic uremic syndrome (aHUS) is a diagnosis that has captured the interest of specialists across multiple fields. The hallmark features of aHUS are microangiopathic hemolysis and thrombocytopenia, which creates a diagnostic dilemma because of the occurrence of these findings in a wide variety of clinical disorders. RECENT FINDINGS In most of the instances, aHUS is a diagnosis of exclusion after ruling out causes such as Shigella toxin, acquired or genetic a disintegrin and metalloproteinase thrombospondin motif 13 deficiency (thrombotic thrombocytopenic purpura), and vitamin B12 deficiency. In the purest sense, aHUS is a genetic condition that is activated (or unmasked) by an environmental exposure. However, it is now evident that complement activation is a feature of many diseases. Variants in complement regulatory genes predispose to microangiopathic hemolysis in many rheumatologic, oncologic, and drug-induced vascular, obstetric, peritransplant, and infectious syndromes. SUMMARY Many 'hemolysis syndromes' overlap clinically with aHUS, and we review the literature on the treatment of these conditions with complement inhibition. New reports on the treatment of C3 glomerulopathy, Shiga toxin-related classic hemolytic uremic syndrome, and medication-related thrombotic microangiopathy will be reviewed as well.
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32
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Zipfel PF, Wiech T, Stea ED, Skerka C. CFHR Gene Variations Provide Insights in the Pathogenesis of the Kidney Diseases Atypical Hemolytic Uremic Syndrome and C3 Glomerulopathy. J Am Soc Nephrol 2020; 31:241-256. [PMID: 31980588 PMCID: PMC7003313 DOI: 10.1681/asn.2019050515] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Sequence and copy number variations in the human CFHR-Factor H gene cluster comprising the complement genes CFHR1, CFHR2, CFHR3, CFHR4, CFHR5, and Factor H are linked to the human kidney diseases atypical hemolytic uremic syndrome (aHUS) and C3 glomerulopathy. Distinct genetic and chromosomal alterations, deletions, or duplications generate hybrid or mutant CFHR genes, as well as hybrid CFHR-Factor H genes, and alter the FHR and Factor H plasma repertoire. A clear association between the genetic modifications and the pathologic outcome is emerging: CFHR1, CFHR3, and Factor H gene alterations combined with intact CFHR2, CFHR4, and CFHR5 genes are reported in atypical hemolytic uremic syndrome. But alterations in each of the five CFHR genes in the context of an intact Factor H gene are described in C3 glomerulopathy. These genetic modifications influence complement function and the interplay of the five FHR proteins with each other and with Factor H. Understanding how mutant or hybrid FHR proteins, Factor H::FHR hybrid proteins, and altered Factor H, FHR plasma profiles cause pathology is of high interest for diagnosis and therapy.
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Affiliation(s)
- Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany;
- Institute of Microbiology, Friedrich-Schiller-University, Jena, Germany; and
| | - Thorsten Wiech
- Section of Nephropathology, Institute of Pathology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Emma D Stea
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
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33
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Abstract
PURPOSE OF REVIEW The purpose of this review is to emphasize that single gene disorders are an important and sometimes unrecognized cause of progressive chronic kidney disease. We provide an overview of the benefits of making a genetic diagnosis, the currently available genetic testing methods and examples of diseases illustrating the impact of a genetic diagnosis. RECENT FINDINGS Although there are now a number of monogenic renal diseases, only a few, such as autosomal dominant polycystic kidney disease (ADPKD), are generally diagnosable without genetic testing. Complicating clinical diagnosis is that many diseases that classically have characteristic renal or extrarenal findings, often present with an incomplete or overlapping phenotype that requires additional testing to be uncovered. Advances in sequencing technology and bioinformatic processing now give us the ability to screen the entire human genome or exome or an organ-limited subset of genes quickly and inexpensively permitting the unbiased interrogation of hundreds of genes, thus removing the need for precision in clinical diagnosis prior to testing. SUMMARY We provide an overview of the principal phenotypes seen in chronic kidney disease with a focus on the cystic diseases and ciliopathies, the glomerular diseases, disorders of renal development and the tubulointerstitial diseases. In each of these phenotypes, we provide a listing of some of the important genes that have been identified to date, a brief discussion of the clinical diagnosis, the role of genetic testing and the differentiation of distinct genetic disorders from acquired and genetic phenocopies.
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34
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Hanna RM, Merin N, Burwick RM, Abdelnour L, Selamet U, Yanny B, Bui P, Fouad M, Kurtz I. Successful use of eculizumab to treat atypical hemolytic uremic syndrome in patients with inflammatory bowel disease. Thromb J 2019; 17:18. [PMID: 31516395 PMCID: PMC6732828 DOI: 10.1186/s12959-019-0207-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 07/31/2019] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Atypical hemolytic uremic syndrome is a rare group of disorders that have in common underlying complement amplifying conditions. These conditions can accelerate complement activation that results in a positive feedback cycle. The known triggers for complement activation can be diverse and include, infection, autoimmune disease, and malignancy. Recent reports suggest that certain autoimmune and rheumatological triggers of complement activation may result in atypical hemolytic uremic syndrome that does not resolve despite treating the underlying disorder. Specifically, patients with systemic lupus erythematosus and microangiopathic hemolysis may not respond to treatment of their underlying rheumatological trigger but responded to complement blockade. CASE PRESENTATIONS We report two patients with inflammatory bowel disease complicated by development of atypical hemolytic uremic syndrome. In both cases, patients were on treatment for inflammatory bowel disease, that was not well controlled/flaring at the time. The first patient is a male who developed Crohn's disease and microangiopathic hemolysis at age 5 and was treated with eculizumab successfully. Discontinuation of the medication led to multiple relapses, and the patient currently is being treated with eculizumab and has normal hematological and stable renal parameters. The second patient is a 49-year-old female with Ulcerative Colitis treated with 6-Mercaptopurine. She developed acute kidney injury and microangiopathic hemolysis. Prompt diagnosis and treatment with eculizumab resulted in the recovery of kidney injury along with a complete hematological response. CONCLUSIONS These two cases are the fifth and sixth patients to be published in the literature with atypical hemolytic uremic syndrome and inflammatory bowel disease treated with complement blockade. This confirms that C5 complement blockade is effective in treating complement mediated thrombotic microangiopathy/atypical hemolytic uremic syndrome when it is triggered in patients with inflammatory bowel disease.
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Affiliation(s)
- Ramy M. Hanna
- Department of Medicine, Division of Nephrology, UCLA David Geffen School of Medicine, Room 7-155, Factor Bldg. 700 Tiverton Ave, Los Angeles, CA 90095 USA
- Department of Medicine, Division of Nephrology, University of California Irvine School of Medicine, Irvine CA, USA
| | - Noah Merin
- Department of Medicine, Division of Hematology Oncology, Cedars Sinai Medical Center, Los Angeles, USA
| | - Richard M. Burwick
- Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, Cedars Sinai Medical Center, Los Angeles, USA
| | - Lama Abdelnour
- Department of Medicine, Division of Nephrology, UCLA David Geffen School of Medicine, Room 7-155, Factor Bldg. 700 Tiverton Ave, Los Angeles, CA 90095 USA
| | - Umut Selamet
- Department of Medicine, Division of Nephrology, UCLA David Geffen School of Medicine, Room 7-155, Factor Bldg. 700 Tiverton Ave, Los Angeles, CA 90095 USA
| | - Beshoy Yanny
- Department of Medicine, Division of Digestive Diseases, UCLA David Geffen School of Medicine, Los Angeles, USA
| | - Patrick Bui
- Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, USA
| | - Mary Fouad
- Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, USA
| | - Ira Kurtz
- Department of Medicine, Division of Nephrology, UCLA David Geffen School of Medicine, Room 7-155, Factor Bldg. 700 Tiverton Ave, Los Angeles, CA 90095 USA
- UCLA Brain Research Institute, Los Angeles, USA
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35
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Bagga A, Khandelwal P, Mishra K, Thergaonkar R, Vasudevan A, Sharma J, Patnaik SK, Sinha A, Sethi S, Hari P, Dragon-Durey MA. Hemolytic uremic syndrome in a developing country: Consensus guidelines. Pediatr Nephrol 2019; 34:1465-1482. [PMID: 30989342 DOI: 10.1007/s00467-019-04233-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 01/06/2019] [Accepted: 03/07/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Hemolytic uremic syndrome (HUS) is a leading cause of acute kidney injury in children. Although international guidelines emphasize comprehensive evaluation and treatment with eculizumab, access to diagnostic and therapeutic facilities is limited in most developing countries. The burden of Shiga toxin-associated HUS in India is unclear; school-going children show high prevalence of anti-factor H (FH) antibodies. The aim of the consensus meeting was to formulate guidelines for the diagnosis and management of HUS in children, specific to the needs of the country. METHODS Four workgroups performed literature review and graded research studies addressing (i) investigations, biopsy, genetics, and differential diagnosis; (ii) Shiga toxin, pneumococcal, and infection-associated HUS; (iii) atypical HUS; and (iv) complement blockade. Consensus statements developed by the workgroups were discussed during a consensus meeting in March 2017. RESULTS An algorithm for classification and evaluation was developed. The management of Shiga toxin-associated HUS is supportive; prompt plasma exchanges (PEX) is the chief therapy in patients with atypical HUS. Experts recommend that patients with anti-FH-associated HUS be managed with a combination of PEX and immunosuppressive medications. Indications for eculizumab include incomplete remission with plasma therapy, life-threatening features, complications of PEX or vascular access, inherited defects in complement regulation, and recurrence of HUS in allografts. Priorities for capacity building in regional and national laboratories are highlighted. CONCLUSIONS Limited diagnostic capabilities and lack of access to eculizumab prevent the implementation of international guidelines for HUS in most developing countries. We propose practice guidelines for India, which will perhaps be applicable to other developing countries.
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Affiliation(s)
- Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India.
| | - Priyanka Khandelwal
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Kirtisudha Mishra
- Department of Pediatrics, Chacha Nehru Bal Chikitsalya, New Delhi, India
| | - Ranjeet Thergaonkar
- Department of Pediatrics, Indian Naval Hospital Ship, Kalyani, Visakhapatnam, India
| | - Anil Vasudevan
- Department of Pediatric Nephrology, St. Johns Medical College and Hospital, Bengaluru, India
| | - Jyoti Sharma
- Department of Pediatrics, KEM Hospital, Pune, India
| | - Saroj Kumar Patnaik
- Department of Pediatrics, Army Hospital Research & Referral, New Delhi, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Sidharth Sethi
- Department of Nephrology, Medanta Hospital, New Delhi, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Marie-Agnes Dragon-Durey
- Laboratory of Immunology, Hopital Europeen Georges Pompidou, INSERM UMRS 1138, Paris Descartes University, Paris, France
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Hanna RM, Hasnain H, Abdelnour L, Yanny B, Burwick RM. Atypical hemolytic uremic syndrome in a patient with protein-losing enteropathy. J Int Med Res 2019; 47:4027-4032. [PMID: 31364428 PMCID: PMC6726804 DOI: 10.1177/0300060519864808] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is an ultra-rare disease induced by many triggers, all of which produce a common end phenotype of microangiopathic hemolysis and thrombotic microangiopathy. We herein describe a 63-year-old woman with ongoing protein-losing enteropathy and frequent transudates caused by hypoalbuminemia. The patient was treated with eculizumab with a full hematologic and partial renal response. Protein-losing enteropathy is an inflammatory condition that has been linked with increased complement activation, which can trigger aHUS in patients with loss of CD55 expression. The patient in the present case had an increased estimated glomerular filtration rate but stage IV to V chronic kidney disease. One year later, she remains off dialysis with a stable estimated glomerular filtration rate. We herein report an unusual trigger of complement activation that in turn triggered aHUS in this patient.
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Affiliation(s)
- Ramy M Hanna
- 1 Division of Nephrology, Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, United States
| | - Huma Hasnain
- 1 Division of Nephrology, Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, United States
| | - Lama Abdelnour
- 1 Division of Nephrology, Department of Medicine, UCLA David Geffen School of Medicine, Los Angeles, CA, United States
| | - Beshoy Yanny
- 2 Department of Medicine, Division of Digestive Diseases, Hepatology UCLA David Geffen School of Medicine, Los Angeles, CA, United States
| | - Richard M Burwick
- 3 Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Cedars Sinai Medical Center, Los Angeles, CA, United States
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Clinical promise of next-generation complement therapeutics. Nat Rev Drug Discov 2019; 18:707-729. [PMID: 31324874 DOI: 10.1038/s41573-019-0031-6] [Citation(s) in RCA: 209] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2019] [Indexed: 02/07/2023]
Abstract
The complement system plays a key role in pathogen immunosurveillance and tissue homeostasis. However, subversion of its tight regulatory control can fuel a vicious cycle of inflammatory damage that exacerbates pathology. The clinical merit of targeting the complement system has been established for rare clinical disorders such as paroxysmal nocturnal haemoglobinuria and atypical haemolytic uraemic syndrome. Evidence from preclinical studies and human genome-wide analyses, supported by new molecular and structural insights, has revealed new pathomechanisms and unmet clinical needs that have thrust a new generation of complement inhibitors into clinical development for a variety of indications. This review critically discusses recent clinical milestones in complement drug discovery, providing an updated translational perspective that may guide optimal target selection and disease-tailored complement intervention.
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Schönauer R, Seidel A, Grohmann M, Lindner TH, Bergmann C, Halbritter J. Deleterious Impact of a Novel CFH Splice Site Variant in Atypical Hemolytic Uremic Syndrome. Front Genet 2019; 10:465. [PMID: 31156713 PMCID: PMC6530248 DOI: 10.3389/fgene.2019.00465] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/30/2019] [Indexed: 12/21/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a heterogeneous disorder characterized by microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and acute kidney injury (AKI). In about 50% of cases, pathogenic variants in genes involved in the innate immune response including complement factors complement factor H (CFH), CFI, CFB, C3, and membrane co-factor protein (MCP/CD46) put patients at risk for uncontrolled activation of the alternative complement pathway. As aHUS is characterized by incomplete penetrance and presence of additional triggers for disease manifestation, genetic variant interpretation is challenging and streamlined functional variant evaluation is urgently needed. Here, we report the case of a 27-year-old female without previous medical and family history who presented with confusion, petechial bleeding, and anuric AKI. Kidney biopsy revealed glomerular thrombotic microangiopathy (TMA). Targeted next generation sequencing identified a paternally transmitted novel heterozygous splice site variant in the CFH gene [c.3134-2A>G; p.Asp1045_Thr1053del] which resulted in a partial in-frame deletion of exon 20 transcript as determined by cDNA analysis. On the protein level, the concomitant loss of 9 amino acids in the short consensus repeat (SCR) domains 17 and 18 of CFH includes a highly conserved cysteine residue, which is assumed to be essential for proper structural folding and protein function. Treatment with steroids, plasmapheresis, and the complement inhibitor eculizumab led to complete hematological and clinical remission after several months and stable renal function up to 6 years later. In conclusion, genetic investigation for pathogenic variants and evaluation of their functional impact, in particular in the case of splice site variants, is clinically relevant and enables not only better molecular understanding but helps to guide therapy with complement inhibitors.
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Affiliation(s)
- Ria Schönauer
- Division of Nephrology, University Hospital Leipzig, Leipzig, Germany
| | - Anna Seidel
- Division of Nephrology, University Hospital Leipzig, Leipzig, Germany
| | - Maik Grohmann
- Center for Human Genetics, Bioscientia, Ingelheim, Germany
| | - Tom H Lindner
- Division of Nephrology, University Hospital Leipzig, Leipzig, Germany
| | | | - Jan Halbritter
- Division of Nephrology, University Hospital Leipzig, Leipzig, Germany
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Aigner C, Schmidt A, Gaggl M, Sunder-Plassmann G. An updated classification of thrombotic microangiopathies and treatment of complement gene variant-mediated thrombotic microangiopathy. Clin Kidney J 2019; 12:333-337. [PMID: 31198225 PMCID: PMC6543965 DOI: 10.1093/ckj/sfz040] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Indexed: 12/21/2022] Open
Abstract
Conditions presenting with signs of thrombotic microangiopathies (TMAs) comprise a wide spectrum of different diseases. While pathological hallmarks are thrombosis of arterioles and capillaries, clinical signs are mechanical haemolysis, thrombocytopenia and acute renal injury or neurological manifestations. The current classification of various syndromes of TMA is heterogeneous and often does not take the underlying pathophysiology into consideration. Therefore we propose a simplified classification based on the aetiology of different syndromes leading to TMA. We propose to categorize different TMA syndromes in hereditary and acquired forms and classify them based on the genetic background or underlying conditions. Of course, this classification is not always distinctly applicable in each case and from time to time reassessment of the established diagnosis is strongly recommended. The recommended treatment of TMA in the past was plasma exchange (PE). However, recently, the terminal complement inhibitor eculizumab became commercially available and has shown promising results in different open-label studies and case series. In our centre, first-line therapy is PE; however, patients are instantly switched to complement inhibitory therapy in case of treatment failure or intolerance.
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Affiliation(s)
- Christof Aigner
- Department of Medicine III, Division of Nephrology and Dialysis, Medical University of Vienna, Vienna, Austria
| | - Alice Schmidt
- Department of Medicine III, Division of Nephrology and Dialysis, Medical University of Vienna, Vienna, Austria
| | - Martina Gaggl
- Department of Medicine III, Division of Nephrology and Dialysis, Medical University of Vienna, Vienna, Austria
| | - Gere Sunder-Plassmann
- Department of Medicine III, Division of Nephrology and Dialysis, Medical University of Vienna, Vienna, Austria
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Ottlewski I, Münch J, Wagner T, Schönauer R, Bachmann A, Weimann A, Hentschel J, Lindner TH, Seehofer D, Bergmann C, Jamra RA, Halbritter J. Value of renal gene panel diagnostics in adults waiting for kidney transplantation due to undetermined end-stage renal disease. Kidney Int 2019; 96:222-230. [PMID: 31027891 DOI: 10.1016/j.kint.2019.01.038] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 01/21/2019] [Accepted: 01/31/2019] [Indexed: 12/11/2022]
Abstract
End-stage renal disease (ESRD) of undetermined etiology is highly prevalent and constitutes a significant clinical challenge, particularly in the context of kidney transplantation (KT). Despite the identification of numerous rare hereditary nephropathies over the last few decades, patients with undetermined ESRD are not being systematically investigated for rare genetic causes in clinical practice. To address this, we utilized mutation analysis in patients on the kidney transplant waitlist and scrutinized underlying renal diagnoses of 142 patients in a single center KT-waitlist. This cohort was stratified into 85 cases of determined and 57 cases of undetermined ESRD. The latter patients were analyzed by a renal gene panel for mutations in 209 genes associated with ESRD. The most likely genetic diagnoses in 12% of the tested individuals with undetermined ESRD were established. All of these patients showed mutations in genes encoding components of the glomerular filtration barrier. Taken together, hereditary nephropathies, including autosomal dominant polycystic kidney disease, were identified in 35 of the 142 patients of the waitlist cohort. By significantly increasing the proportion of hereditary diagnoses from 29 to 35 patients, the rate of undetermined ESRD significantly decreased from 57 to 51 patients. This study demonstrates the beneficial use of genetic diagnostics in significantly unraveling undetermined ESRD cases prior to KT. Thus, in the absence of renal histology or the presence of unspecific histological conditions, such as hypertensive nephrosclerosis, focal segmental glomerulosclerosis or thrombotic microangiopathy, genetic analysis may provide a robust and specific renal diagnosis and allow for optimizing pre- and post-KT management.
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Affiliation(s)
- Isabel Ottlewski
- Division of Nephrology, Department of Internal Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Johannes Münch
- Division of Nephrology, Department of Internal Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Timo Wagner
- Bioscientia, Institute of Human Genetics, Ingelheim, Germany
| | - Ria Schönauer
- Division of Nephrology, Department of Internal Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Anette Bachmann
- Division of Nephrology, Department of Internal Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Antje Weimann
- Department of Visceral, Transplant, Thoracic, and Vascular Surgery, University Hospital Leipzig, Leipzig, Germany
| | - Julia Hentschel
- Institute of Human Genetics, University Hospital Leipzig, Leipzig, Germany
| | - Tom H Lindner
- Division of Nephrology, Department of Internal Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Daniel Seehofer
- Department of Visceral, Transplant, Thoracic, and Vascular Surgery, University Hospital Leipzig, Leipzig, Germany
| | - Carsten Bergmann
- Bioscientia, Institute of Human Genetics, Ingelheim, Germany; Department of Medicine, University Hospital Freiburg, Freiburg, Germany
| | - Rami Abou Jamra
- Institute of Human Genetics, University Hospital Leipzig, Leipzig, Germany
| | - Jan Halbritter
- Division of Nephrology, Department of Internal Medicine, University Hospital Leipzig, Leipzig, Germany.
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Gavriilaki E, Anagnostopoulos A, Mastellos DC. Complement in Thrombotic Microangiopathies: Unraveling Ariadne's Thread Into the Labyrinth of Complement Therapeutics. Front Immunol 2019; 10:337. [PMID: 30891033 PMCID: PMC6413705 DOI: 10.3389/fimmu.2019.00337] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/08/2019] [Indexed: 12/20/2022] Open
Abstract
Thrombotic microangiopathies (TMAs) are a heterogeneous group of syndromes presenting with a distinct clinical triad: microangiopathic hemolytic anemia, thrombocytopenia, and organ damage. We currently recognize two major entities with distinct pathophysiology: thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). Beyond them, differential diagnosis also includes TMAs associated with underlying conditions, such as drugs, malignancy, infections, scleroderma-associated renal crisis, systemic lupus erythematosus (SLE), malignant hypertension, transplantation, HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets), and disseminated intravascular coagulation (DIC). Since clinical presentation alone is not sufficient to differentiate between these entities, robust pathophysiological features need to be used for early diagnosis and appropriate treatment. Over the last decades, our understanding of the complement system has evolved rapidly leading to the characterization of diseases which are fueled by complement dysregulation. Among TMAs, complement-mediated HUS (CM-HUS) has long served as a disease model, in which mutations of complement-related genes represent the first hit of the disease and complement inhibition is an effective and safe strategy. Based on this knowledge, clinical conditions resembling CM-HUS in terms of phenotype and genotype have been recognized. As a result, the role of complement in TMAs is rapidly expanding in recent years based on genetic and functional studies. Herein we provide an updated overview of key pathophysiological processes underpinning complement activation and dysregulation in TMAs. We also discuss emerging clinical challenges in streamlining diagnostic algorithms and stratifying TMA patients that could benefit more from complement modulation. With the advent of next-generation complement therapeutics and suitable disease models, these translational perspectives could guide a more comprehensive, disease- and target-tailored complement intervention in these disorders.
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Affiliation(s)
- Eleni Gavriilaki
- BMT Unit, Hematology Department, G. Papanicolaou Hospital, Thessaloniki, Greece
| | | | - Dimitrios C Mastellos
- Division of Biodiagnostic Sciences and Technologies, INRASTES, National Center for Scientific Research Demokritos, Athens, Greece
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