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Abstract
Dysregulation and accelerated activation of the alternative pathway (AP) of complement is known to cause or accentuate several pathologic conditions in which kidney injury leads to the appearance of hematuria and proteinuria and ultimately to the development of chronic renal failure. Multiple genetic and acquired defects involving plasma- and membrane-associated proteins are probably necessary to impair the protection of host tissues and to confer a significant predisposition to AP-mediated kidney diseases. This review aims to explore how our current understanding will make it possible to identify the mechanisms that underlie AP-mediated kidney diseases and to discuss the available clinical evidence that supports complement-directed therapies. Although the value of limiting uncontrolled complement activation has long been recognized, incorporating complement-targeted treatments into clinical use has proved challenging. Availability of anti-complement therapy has dramatically transformed the outcome of atypical hemolytic uremic syndrome, one of the most severe kidney diseases. Innovative drugs that directly counteract AP dysregulation have also opened new perspectives for the management of other kidney diseases in which complement activation is involved. However, gained experience indicates that the choice of drug should be tailored to each patient's characteristics, including clinical, histologic, genetic, and biochemical parameters. Successfully treating patients requires further research in the field and close collaboration between clinicians and researchers who have special expertise in the complement system.
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Affiliation(s)
- Erica Daina
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Monica Cortinovis
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Giuseppe Remuzzi
- Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
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Kumar S, Bhagia G, Kaae J. A Rare Case of Atypical Hemolytic Uremia Syndrome Triggered by Influenza Vaccination. Cureus 2022; 14:e23577. [PMID: 35494971 PMCID: PMC9045680 DOI: 10.7759/cureus.23577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2022] [Indexed: 11/08/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) occurs in patients with defective alternative complement pathways, making them susceptible to thrombotic microangiopathy (thrombocytopenia, intravascular hemolysis, and renal failure), and is usually triggered by infectious agents. Influenza and Streptococcus pneumonia are known triggers for aHUS. However, influenza vaccination triggering aHUS is rarely reported. We present a 30-year-old male who presented with chills, abdominal discomfort, and night sweats after receiving the influenza vaccine. The patient had thrombocytopenia, elevated creatinine, blood urea nitrogen, liver enzymes, and bilirubin with schistocytes with peripheral smear. ADAMTS13 activity was normal so the patient was diagnosed with aHUS. The patient improved with eculizumab and was ultimately found to have a mutation in CD46, which made him susceptible to aHUS. This case shows patients with dysregulated alternative complement pathways may be predisposed to develop aHUS after receiving influenza vaccination.
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Whole-exome analysis of adolescents with low VWF and heavy menstrual bleeding identifies novel genetic associations. Blood Adv 2021; 6:420-428. [PMID: 34807970 PMCID: PMC8791588 DOI: 10.1182/bloodadvances.2021005118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 11/01/2021] [Indexed: 11/20/2022] Open
Abstract
HMB is associated with rare and common variants in genes related to anemias and bleeding disorders. These are the first exome-sequencing results from patients with HMB, as well as their comparison with control exomes.
Adolescents with low von Willebrand factor (VWF) levels and heavy menstrual bleeding (HMB) experience significant morbidity. There is a need to better characterize these patients genetically and improve our understanding of the pathophysiology of bleeding. We performed whole-exome sequencing on 86 postmenarchal patients diagnosed with low VWF levels (30-50 IU/dL) and HMB and compared them with 660 in-house controls. We compared the number of rare stop-gain/stop-loss and rare ClinVar “pathogenic” variants between cases and controls, as well as performed gene burden and gene-set burden analyses. We found an enrichment in cases of rare stop-gain/stop-loss variants in genes involved in bleeding disorders and an enrichment of rare ClinVar “pathogenic” variants in genes involved in anemias. The 2 most significant genes in the gene burden analysis, CFB and DNASE2, are associated with atypical hemolytic uremia and severe anemia, respectively. VWF also surpassed exome-wide significance in the gene burden analysis (P = 7.31 × 10−6). Gene-set burden analysis revealed an enrichment of rare nonsynonymous variants in cases in several hematologically relevant pathways. Further, common variants in FERMT2, a gene involved in the regulation of hemostasis and angiogenesis, surpassed genome-wide significance. We demonstrate that adolescents with HMB and low VWF have an excess of rare nonsynonymous and pathogenic variants in genes involved in bleeding disorders and anemia. Variants of variable penetrance in these genes may contribute to the spectrum of phenotypes observed in patients with HMB and could partially explain the bleeding phenotype. By identifying patients with HMB who possess these variants, we may be able to improve risk stratification and patient outcomes.
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Aradottir SS, Kristoffersson AC, Roumenina LT, Bjerre A, Kashioulis P, Palsson R, Karpman D. Factor D Inhibition Blocks Complement Activation Induced by Mutant Factor B Associated With Atypical Hemolytic Uremic Syndrome and Membranoproliferative Glomerulonephritis. Front Immunol 2021; 12:690821. [PMID: 34177949 PMCID: PMC8222914 DOI: 10.3389/fimmu.2021.690821] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 05/10/2021] [Indexed: 12/30/2022] Open
Abstract
Complement factor B (FB) mutant variants are associated with excessive complement activation in kidney diseases such as atypical hemolytic uremic syndrome (aHUS), C3 glomerulopathy and membranoproliferative glomerulonephritis (MPGN). Patients with aHUS are currently treated with eculizumab while there is no specific treatment for other complement-mediated renal diseases. In this study the phenotype of three FB missense variants, detected in patients with aHUS (D371G and E601K) and MPGN (I242L), was investigated. Patient sera with the D371G and I242L mutations induced hemolysis of sheep erythrocytes. Mutagenesis was performed to study the effect of factor D (FD) inhibition on C3 convertase-induced FB cleavage, complement-mediated hemolysis, and the release of soluble C5b-9 from glomerular endothelial cells. The FD inhibitor danicopan abrogated C3 convertase-associated FB cleavage to the Bb fragment in patient serum, and of the FB constructs, D371G, E601K, I242L, the gain-of-function mutation D279G, and the wild-type construct, in FB-depleted serum. Furthermore, the FD-inhibitor blocked hemolysis induced by the D371G and D279G gain-of-function mutants. In FB-depleted serum the D371G and D279G mutants induced release of C5b-9 from glomerular endothelial cells that was reduced by the FD-inhibitor. These results suggest that FD inhibition can effectively block complement overactivation induced by FB gain-of-function mutations.
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Affiliation(s)
| | | | - Lubka T Roumenina
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, Paris, France
| | - Anna Bjerre
- Division of Pediatric and Adolescent Medicine, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Pavlos Kashioulis
- Department of Molecular and Clinical Medicine/Nephrology, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Runolfur Palsson
- Landspitali - The National University Hospital of Iceland, Reykjavik, Iceland.,Faculty of Medicine, School of Health Sciences, University of Iceland, Reykjavík, Iceland
| | - Diana Karpman
- Department of Pediatrics, Clinical Sciences Lund, Lund University, Lund, Sweden
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5
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Wu D, Chen J, Ling C, Chen Z, Fan J, Sun Q, Meng Q, Liu X. Clinical and Genetic Characteristics of Atypical Hemolytic Uremic Syndrome in Children: A Chinese Cohort Study. Nephron Clin Pract 2021; 145:415-427. [PMID: 33873197 DOI: 10.1159/000513009] [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: 06/04/2020] [Accepted: 11/12/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Atypical hemolytic uremic syndrome (aHUS) is a rare but critical illness. To this date, few studies have reported on the disease in Chinese children. METHODS We studied a Chinese pediatric cohort to delineate the clinical characteristics, genotypes, and prognosis. Ninety-one patients with aHUS were enrolled in this study. RESULTS Fifty-nine children (64.8%) had anti-complement-factor-H autoantibody-associated aHUS (anti-CFH aHUS). Of these children, 21 (46.7%) had complement factor-H-related protein 1 (CFHR1) homozygous deletion, and most patients with CFHR1 homozygous deletion also had complement factor-H-related protein 3 (CFHR3) homozygous deletions (76.2%). Using gene sequencing of 15 candidate genes, we identified 14 genetic variants in 46 aHUS patients, including 5 pathogenic or like pathogenic variants and 9 variants of uncertain significance. The average follow-up time was 46.1 ± 28 months. Among patients with anti-CFH aHUS, there was a correlation between CFHR1 homozygous deletion and patients with persistent proteinuria (odds ratio [OR] 6.954, 95% confidence interval [CI] 1.033-46.821, p = 0.046). As of the last follow-up, ESRD or deaths occurred in 3.6% of the children with anti-CFH aHUS and 26.7% of children with aHUS who were negative for anti-CFH. CONCLUSIONS Anti-complement-factor-H antibody positivity is the main cause of morbidity in Chinese children with aHUS. There may be a correlation between CFHR1 homozygous deletion and persistent proteinuria. Comprehensive assessment of anti-CFH antibodies and genetic variants is essential for the management of aHUS children.
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Affiliation(s)
- Dan Wu
- Department of Nephrology, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Jiahui Chen
- Department of Pediatrics, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Chen Ling
- Department of Nephrology, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Zhi Chen
- Department of Nephrology, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Jianfeng Fan
- Department of Nephrology, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Qiang Sun
- Department of Nephrology, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Qun Meng
- Department of Nephrology, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Xiaorong Liu
- Department of Nephrology, Beijing Children's Hospital, Capital Medical University, Beijing, China
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Chhakchhuak M, Agarwal J. Novel Variation in CFB Adult Onset Atypical Hemolytic Uremic Syndrome: A Case Report and Review. Indian J Nephrol 2020; 30:286-289. [PMID: 33273796 PMCID: PMC7699664 DOI: 10.4103/ijn.ijn_265_19] [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: 07/31/2019] [Revised: 09/05/2019] [Accepted: 10/31/2000] [Indexed: 11/17/2022] Open
Abstract
We report a case of 47-year-old male with atypical hemolytic uremic syndrome (aHUS). He had low C3 levels and whole exome sequencing revealed heterozygous missense novel variation in exon 8 of the gene encoding complement factor B (CFB), leading to substitution of leucine for proline at codon 369 (c.1106C>T; p.Pro369Leu). Following plasma exchanges and hemodialysis, the patient achieved hematological remission and became dialysis independent.
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Affiliation(s)
- Malsawmkima Chhakchhuak
- Department of Nephrology, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
| | - Jony Agarwal
- Department of Nephrology, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
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Chauvet S, Berthaud R, Devriese M, Mignotet M, Vieira Martins P, Robe-Rybkine T, Miteva MA, Gyulkhandanyan A, Ryckewaert A, Louillet F, Merieau E, Mestrallet G, Rousset-Rouvière C, Thervet E, Hogan J, Ulinski T, Villoutreix BO, Roumenina L, Boyer O, Frémeaux-Bacchi V. Anti-Factor B Antibodies and Acute Postinfectious GN in Children. J Am Soc Nephrol 2020; 31:829-840. [PMID: 32034108 DOI: 10.1681/asn.2019080851] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 12/26/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The pathophysiology of the leading cause of pediatric acute nephritis, acute postinfectious GN, including mechanisms of the pathognomonic transient complement activation, remains uncertain. It shares clinicopathologic features with C3 glomerulopathy, a complement-mediated glomerulopathy that, unlike acute postinfectious GN, has a poor prognosis. METHODS This retrospective study investigated mechanisms of complement activation in 34 children with acute postinfectious GN and low C3 level at onset. We screened a panel of anticomplement protein autoantibodies, carried out related functional characterization, and compared results with those of 60 children from the National French Registry who had C3 glomerulopathy and persistent hypocomplementemia. RESULTS All children with acute postinfectious GN had activation of the alternative pathway of the complement system. At onset, autoantibodies targeting factor B (a component of the alternative pathway C3 convertase) were found in a significantly higher proportion of children with the disorder versus children with hypocomplementemic C3 glomerulopathy (31 of 34 [91%] versus 4 of 28 [14%], respectively). In acute postinfectious GN, anti-factor B autoantibodies were transient and correlated with plasma C3 and soluble C5b-9 levels. We demonstrated that anti-factor B antibodies enhance alternative pathway convertase activity in vitro, confirming their pathogenic effect. We also identified crucial antibody binding sites on factor B, including one correlated to disease severity. CONCLUSIONS These findings elucidate the pathophysiologic mechanisms underlying acute postinfectious GN by identifying anti-factor B autoantibodies as contributing factors in alternative complement pathway activation. At onset of a nephritic syndrome with low C3 level, screening for anti-factor B antibodies might help guide indications for kidney biopsy to avoid misdiagnosed chronic glomerulopathy, such as C3 glomerulopathy, and to help determine therapy.
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Affiliation(s)
- Sophie Chauvet
- Inflammation, Complement and Cancer Team, Cordeliers Research Center, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche (UMR) S1138, Paris, France.,Departments of Nephrology and.,Paris University, Paris, France
| | - Romain Berthaud
- Paris University, Paris, France.,Department of Pediatric Nephrology, AP-HP, Necker Hospital - Sick Children, Paris, France
| | - Magali Devriese
- Immunology, Assistance Publique-Hôpitaux de Paris (AP-HP), Georges Pompidou European Hospital, Paris, France
| | - Morgane Mignotet
- Immunology, Assistance Publique-Hôpitaux de Paris (AP-HP), Georges Pompidou European Hospital, Paris, France
| | - Paula Vieira Martins
- Immunology, Assistance Publique-Hôpitaux de Paris (AP-HP), Georges Pompidou European Hospital, Paris, France
| | - Tania Robe-Rybkine
- Inflammation, Complement and Cancer Team, Cordeliers Research Center, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche (UMR) S1138, Paris, France
| | - Maria A Miteva
- Paris University, Paris, France.,INSERM U1268 Medicinal Chemistry and Translational Research, Cibles Thérapeutiques et Conception du Médicament UMR8038 Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Aram Gyulkhandanyan
- University of Paris Diderot, Sorbonne Paris Cité, Molécules Thérapeutiques In Silico, INSERM UMR S973, Paris, France
| | | | | | - Elodie Merieau
- Department of Pediatric Nephrology, Tours Hospital, Tours, France
| | - Guillaume Mestrallet
- Department of Pediatry, Villefranche sur Soane Hospital, Villefranche sur Soane, France
| | | | - Eric Thervet
- Departments of Nephrology and.,Paris University, Paris, France
| | - Julien Hogan
- Department of Pediatric Nephrology, AP-HP, Robert Debré Hospital, Paris, France
| | - Tim Ulinski
- Department of Pediatric Nephrology, AP-HP, Trousseau Hospital, Paris, France
| | - Bruno O Villoutreix
- Paris University, Paris, France.,Laboratory of cristallography and biological Nuclear magnetic resonance, UMR 8015 CNRS, Paris, France; and
| | - Lubka Roumenina
- Inflammation, Complement and Cancer Team, Cordeliers Research Center, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche (UMR) S1138, Paris, France
| | - Olivia Boyer
- Paris University, Paris, France.,Department of Pediatric Nephrology, AP-HP, Necker Hospital - Sick Children, Paris, France.,Reference Center for Hereditary Kidney and Childhood Diseases (MARHEA), Imagine Institute, Paris, France
| | - Véronique Frémeaux-Bacchi
- Inflammation, Complement and Cancer Team, Cordeliers Research Center, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité Mixte de Recherche (UMR) S1138, Paris, France; .,Immunology, Assistance Publique-Hôpitaux de Paris (AP-HP), Georges Pompidou European Hospital, Paris, France.,Paris University, Paris, France
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8
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Thergaonkar RW, Narang A, Gurjar BS, Tiwari P, Puraswani M, Saini H, Sinha A, Varma B, Mukerji M, Hari P, Bagga A. Targeted exome sequencing in anti-factor H antibody negative HUS reveals multiple variations. Clin Exp Nephrol 2017; 22:653-660. [PMID: 28939980 DOI: 10.1007/s10157-017-1478-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 09/03/2017] [Indexed: 02/01/2023]
Abstract
BACKGROUND Genetic susceptibility to atypical hemolytic uremic syndrome (aHUS) may lie within genes regulating or activating the alternate complement and related pathways converging on endothelial cell activation. METHODS We tested 32 Indian patients of aHUS negative for antibodies to complement factor H for genetic variations in a panel of 15 genes, i.e., CFH, CFHR1-5, CFI, CFB, C3, CD46, MASP2, DGKE, ADAMTS13, THBD and PLG using next-generation DNA sequencing and for copy number variation in CFHR1-3. RESULTS Despite absence of a public database of exome variations in the Indian population and limited functional studies, we could establish a genetic diagnosis in 6 (18.8%) patients using a stringent scheme of prioritization. One patient carried a likely pathogenic variation. The number of patients carrying possibly pathogenic variation was as follows: 1 variation: 5 patients, 2 variations: 9 patients, 3 variations: 5 patients, 4 variations: 9 patients, 5 variations: 2 patients and 6 variations: 2 patients. Homozygous deletion of CFHR1-3 was present in five patients; none of these carried a diagnostic genetic variation. Patients with or without diagnostic variation did not differ significantly in terms of enrichment of genetic variations that were rare/novel or predicted deleterious, or for possible environmental triggers. CONCLUSION We conclude that genetic testing for multiple genes in patients with aHUS negative for anti-FH antibodies reveals multiple candidate variations that require prioritization. Population data on variation frequency of the Indian population and supportive functional studies are likely to improve diagnostic yield.
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Affiliation(s)
- R W Thergaonkar
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Ankita Narang
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | | | - Pradeep Tiwari
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Mamta Puraswani
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Himanshi Saini
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Binuja Varma
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Mitali Mukerji
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, 110029, India.
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Noronha N, Costa FD, Dias A, Dinis A. Complement factor B mutation-associated aHUS and myocardial infarction. BMJ Case Rep 2017; 2017:bcr-2017-219716. [PMID: 28710236 DOI: 10.1136/bcr-2017-219716] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
A 6-month-old female infant was referred with a 3-day history of low-grade fever, slight nasal congestion and rhinorrhoea. On admission, the clinical findings were unremarkable and she was discharged home. However, she became progressively more listless with a decreased urine output and was once again seen in the emergency department. Analytically she was found to have metabolic acidosis, hyperkalaemia, thrombocytopaenia, anaemia and schistocytes in the peripheral blood smear. Based on these findings, the diagnosis of haemolyticâ-uremic syndrome was made. A few hours postadmission, there was an abrupt clinical deterioration. She went into cardiorespiratory arrest and she was successfully resuscitated. An ST-segment elevation was noted on the ECG monitor and the troponin I levels were raised, suggesting myocardial infarction. Despite intensive supportive therapy, she went into refractory shock and died within 30 hours.
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Affiliation(s)
- Natália Noronha
- Serviáo de Cuidados Intensivos Pediátricos, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Portugal
| | - Filipa Dias Costa
- Serviáo de Cuidados Intensivos Pediátricos, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Portugal
| | - Andrea Dias
- Serviáo de Cuidados Intensivos Pediátricos, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Portugal
| | - Alexandra Dinis
- Serviáo de Cuidados Intensivos Pediátricos, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, Portugal
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Fidalgo T, Martinho P, Pinto CS, Oliveira AC, Salvado R, Borràs N, Coucelo M, Manco L, Maia T, Mendes MJ, Del Orbe Barreto R, Corrales I, Vidal F, Ribeiro ML. Combined study of ADAMTS13 and complement genes in the diagnosis of thrombotic microangiopathies using next-generation sequencing. Res Pract Thromb Haemost 2017; 1:69-80. [PMID: 30046676 PMCID: PMC6058207 DOI: 10.1002/rth2.12016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/15/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The 2 main forms of thrombotic microangiopathy (TMA) are thrombotic thrombocytopenic purpura (TTP) and atypical hemolytic uremic syndrome (aHUS). Deficiency of ADAMTS13 and dysregulation of the complement pathway result in TTP and aHUS, respectively; however, overlap of their clinical characteristics makes differential diagnosis challenging. OBJECTIVES AND METHODS We aimed to develop a TMA diagnosis workflow based on ADAMTS13 activity and screening of ADAMTS13 and complement genes using a custom next-generation sequencing (NGS) gene panel. PATIENTS For this, from a cohort of 154 Portuguese patients with acute TMA, the genotype-phenotype correlations were analyzed in 7 hereditary TTP (ADAMTS13 activity <10%, no inhibitor), 36 acquired TTP (ADAMTS13 activity <10%, presence of an inhibitor), and in 34 presumable aHUS. RESULTS In total, 37 different rare variants, 8 of which novel (in ADAMTS13,CFH, and CD46), were identified across 7 genes. Thirteen TTP patients were homozygous (n=6), compound heterozygous (n=2), and heterozygous (n=5) for 11 ADAMTS13 variants (6 pathogenic mutations). Among the 34 aHUS patients, 17 were heterozygous for 23 variants in the different complement genes with distinct consequences, ranging from single pathogenic mutations associated with complete disease penetrance to benign variants that cause aHUS only when combined with other variants and/or CFH and CD46 risk haplotypes or CFHR1-3 deletion. CONCLUSIONS Our study provides evidence of the usefulness of the NGS panel as an excellent technology that enables more rapid diagnosis of TMA, and is a valuable asset in clinical practice to discriminate between TTP and aHUS.
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Affiliation(s)
- Teresa Fidalgo
- Department of Clinical HaematologyCentro Hospitalar e Universitário de CoimbraCoimbraPortugal
| | - Patrícia Martinho
- Department of Clinical HaematologyCentro Hospitalar e Universitário de CoimbraCoimbraPortugal
| | - Catarina S. Pinto
- Department of Clinical HaematologyCentro Hospitalar e Universitário de CoimbraCoimbraPortugal
| | - Ana C. Oliveira
- Department of Clinical HaematologyCentro Hospitalar e Universitário de CoimbraCoimbraPortugal
| | - Ramon Salvado
- Department of Clinical HaematologyCentro Hospitalar e Universitário de CoimbraCoimbraPortugal
| | - Nina Borràs
- Congenital CoagulopathiesBlood and Tissue BankBarcelonaSpain
- Molecular Diagnosis and TherapyVall d'Hebron Research InstituteUniversitat Autònoma de Barcelona (VHIR‐UAB)BarcelonaSpain
| | - Margarida Coucelo
- Department of Clinical HaematologyCentro Hospitalar e Universitário de CoimbraCoimbraPortugal
| | - Licínio Manco
- Research Centre for Anthropology and Health (CIAS), Department of Life SciencesUniversity of CoimbraCoimbraPortugal
| | - Tabita Maia
- Department of Clinical HaematologyCentro Hospitalar e Universitário de CoimbraCoimbraPortugal
| | - M. João Mendes
- Department of Clinical HaematologyCentro Hospitalar e Universitário de CoimbraCoimbraPortugal
| | | | - Irene Corrales
- Congenital CoagulopathiesBlood and Tissue BankBarcelonaSpain
- Molecular Diagnosis and TherapyVall d'Hebron Research InstituteUniversitat Autònoma de Barcelona (VHIR‐UAB)BarcelonaSpain
| | - Francisco Vidal
- Congenital CoagulopathiesBlood and Tissue BankBarcelonaSpain
- Molecular Diagnosis and TherapyVall d'Hebron Research InstituteUniversitat Autònoma de Barcelona (VHIR‐UAB)BarcelonaSpain
| | - M. Letícia Ribeiro
- Department of Clinical HaematologyCentro Hospitalar e Universitário de CoimbraCoimbraPortugal
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11
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Alfakeeh K, Azar M, Alfadhel M, Abdullah AM, Aloudah N, Alsaad KO. Rare genetic variant in the CFB gene presenting as atypical hemolytic uremic syndrome and immune complex diffuse membranoproliferative glomerulonephritis, with crescents, successfully treated with eculizumab. Pediatr Nephrol 2017; 32:885-891. [PMID: 28210841 DOI: 10.1007/s00467-016-3577-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 12/25/2016] [Accepted: 12/28/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND Complement factor B gene (CFB) is an important component of the alternate pathway of complement activation that provides an active subunit that associates with C3b to form the C3 convertase, which is an essential element in complement activation. Among the complement-associated disorders, mutations and pathogenic variants in the CFB gene are relatively rare phenomena. Moreover, mutated CFB affiliation with immune-complex diffuse membranoproliferative glomerulonephritis (IC-MPGN) and atypical hemolytic uremic syndrome (aHUS) are considered a highly rare occurrence. CASE PRESENTATION We describe the clinical presentation, course, and pathological findings in a 7-year-old boy who has confirmed CFB heterozygous variants with pathological features compatible with IC-MPGN. Mutational analysis revealed a heterozygous variant p.Glu566Arg in exon 13 of the CFB gene. The patient did not respond to steroids and mycophenolate mofetil (MMF) therapy but responded clinically and biochemically to eculizumab treatment. This is the first case report of CFB alteration associated with IC-MPGN and aHUS that was successfully treated with eculizumab. CONCLUSIONS Heterozygous variants in the CFB gene can be pathogenic and associated with IC-MPGN and aHUS. Early diagnosis and prompt management can be essential in preventing end-stage renal disease. Eculizumab may provide an effective modality of treatment.
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Affiliation(s)
- Khalid Alfakeeh
- King Saud bin Abdulaziz University for Health Sciences, Nephrology Division, Department of Pediatrics, King Abdulaziz Medical City, MNG-HA, Riyadh, Saudi Arabia. .,Department of Paediatrics, Division of Nephrology, King Abdullah Specialised Children Hospital, Mail Code 1940, King Abdulaziz Medical City, P. O. Box 22490, Riyadh, 11426, Kingdom of Saudi Arabia.
| | - Mohammed Azar
- King Saud bin Abdulaziz University for Health Sciences, Nephrology Division, Department of Pediatrics, King Abdulaziz Medical City, MNG-HA, Riyadh, Saudi Arabia
| | - Majid Alfadhel
- Genetics Division, Department of Pediatrics, King Abdulaziz Medical City, MNG-HA, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Alsuayri Mansour Abdullah
- King Saud bin Abdulaziz University for Health Sciences, Nephrology Division, Department of Pediatrics, King Abdulaziz Medical City, MNG-HA, Riyadh, Saudi Arabia
| | - Nourah Aloudah
- Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, MNG-HA, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Khaled O Alsaad
- Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, MNG-HA, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
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Abstract
Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy characterized by intravascular hemolysis, thrombocytopenia, and acute kidney failure. HUS is usually categorized as typical, caused by Shiga toxin-producing Escherichia coli (STEC) infection, as atypical HUS (aHUS), usually caused by uncontrolled complement activation, or as secondary HUS with a coexisting disease. In recent years, a general understanding of the pathogenetic mechanisms driving HUS has increased. Typical HUS (ie, STEC-HUS) follows a gastrointestinal infection with STEC, whereas aHUS is associated primarily with mutations or autoantibodies leading to dysregulated complement activation. Among the 30% to 50% of patients with HUS who have no detectable complement defect, some have either impaired diacylglycerol kinase ε (DGKε) activity, cobalamin C deficiency, or plasminogen deficiency. Some have secondary HUS with a coexisting disease or trigger such as autoimmunity, transplantation, cancer, infection, certain cytotoxic drugs, or pregnancy. The common pathogenetic features in STEC-HUS, aHUS, and secondary HUS are simultaneous damage to endothelial cells, intravascular hemolysis, and activation of platelets leading to a procoagulative state, formation of microthrombi, and tissue damage. In this review, the differences and similarities in the pathogenesis of STEC-HUS, aHUS, and secondary HUS are discussed. Common for the pathogenesis seems to be the vicious cycle of complement activation, endothelial cell damage, platelet activation, and thrombosis. This process can be stopped by therapeutic complement inhibition in most patients with aHUS, but usually not those with a DGKε mutation, and some patients with STEC-HUS or secondary HUS. Therefore, understanding the pathogenesis of the different forms of HUS may prove helpful in clinical practice.
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13
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Association of the C2-CFB locus with non-infectious uveitis, specifically predisposed to Vogt-Koyanagi-Harada disease. Immunol Res 2016; 64:610-8. [PMID: 26671509 DOI: 10.1007/s12026-015-8762-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Complement component 2 (C2) and factor B (CFB) are regulators of complement system and involved in the alternative pathway, which have been identified to be associated with multiple immune-related diseases. This study aimed to investigate the association of these genes with non-infectious intermediate and posterior uveitis. A total of 260 Chinese non-infectious uveitis patients were recruited, including 97 patients with Vogt-Koyanagi-Harada disease (VKH), 70 patients with intermediate uveitis (IU) and 93 patients with Behçet's disease (BD). Two hundred and ninety-three normal control subjects were also recruited. Five SNPs across the C2/CFB region were selected and genotyped using TaqMan SNP Genotyping Assays. Association analysis was adjusted for gender and stratified by different subtypes. The CFB SNP rs1048709 was significantly associated with non-infectious uveitis [P corr = 0.01, OR 1.49 (allele model) and P corr = 0.04, OR 1.58 (dominant model), respectively], and similar association was also detected between rs1048709 and female uveitis patients (P corr = 0.01, OR 1.70 and P corr = 0.049, OR 184, respectively). Moreover, subgroup analyses showed that CFB-rs1048709 was specifically associated with VKH, where significantly higher frequencies of A allele and AA homozygosity were observed in VKH patients compared with controls (P corr = 0.025 and P corr = 0.035, respectively), whereas none of these five SNPs was associated with IU or BD. In addition, a haplotype block across CFB (GTG) was significantly predisposed to uveitis with protective effect (OR 0.66, P corr = 0.048). Our results revealed a significant association of CFB with non-infectious uveitis, particularly predisposed to VKH disease. Genetic differences for uveitis could be gender-specific.
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14
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Nashine S, Chwa M, Kazemian M, Thaker K, Lu S, Nesburn A, Kuppermann BD, Kenney MC. Differential Expression of Complement Markers in Normal and AMD Transmitochondrial Cybrids. PLoS One 2016; 11:e0159828. [PMID: 27486856 PMCID: PMC4972370 DOI: 10.1371/journal.pone.0159828] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 07/09/2016] [Indexed: 12/19/2022] Open
Abstract
Purpose Variations in mitochondrial DNA (mtDNA) and abnormalities in the complement pathways have been implicated in the pathogenesis of age-related macular degeneration (AMD). This study was designed to determine the effects of mtDNA from AMD subjects on the complement pathway. Methods Transmitochondrial cybrids were prepared by fusing platelets from AMD and age-matched Normal subjects with Rho0 (lacking mtDNA) human ARPE-19 cells. Quantitative PCR and Western blotting were performed to examine gene and protein expression profiles, respectively, of complement markers in these cybrids. Bioenergetic profiles of Normal and AMD cybrids were examined using the Seahorse XF24 flux analyzer. Results Significant decreases in the gene and protein expression of complement inhibitors, along with significantly higher levels of complement activators, were found in AMD cybrids compared to Older-Normal cybrids. Seahorse flux data demonstrated that the bioenergetic profiles for Older-Normal and Older-AMD cybrid samples were similar to each other but were lower compared to Young-Normal cybrid samples. Conclusion In summary, since all cybrids had identical nuclei and differed only in mtDNA content, the observed changes in components of complement pathways can be attributed to mtDNA variations in the AMD subjects, suggesting that mitochondrial genome and retrograde signaling play critical roles in this disease. Furthermore, the similar bioenergetic profiles of AMD and Older-Normal cybrids indicate that the signaling between mitochondria and nuclei are probably not via a respiratory pathway.
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Affiliation(s)
- Sonali Nashine
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
| | - Marilyn Chwa
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
| | - Mina Kazemian
- College of Osteopathic Medicine, Touro University Nevada, Nevada, United States of America
| | - Kunal Thaker
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
| | - Stephanie Lu
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
- VA Medical Center Long Beach Hospital, Long Beach, California, United States of America
| | - Anthony Nesburn
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
- Cedars-Sinai Medical Center, Los Angeles, California, United States of America
| | - Baruch D. Kuppermann
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
| | - M. Cristina Kenney
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, United States of America
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, California, United States of America
- * E-mail:
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15
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Zhu Z, Chen H, Gill R, Wang J, Spitalewitz S, Gotlieb V. Diabetic ketoacidosis presenting with atypical hemolytic uremic syndrome associated with a variant of complement factor B in an adult: a case report. J Med Case Rep 2016; 10:38. [PMID: 26911616 PMCID: PMC4765089 DOI: 10.1186/s13256-016-0825-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Accepted: 01/30/2016] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Non-Shiga toxin-associated hemolytic uremic syndrome is known to be caused by dysregulation of the alternative complement pathway. Infections, drugs, pregnancy, bone marrow transplantation, malignancy, and autoimmune disorders have all been reported to trigger episodes of atypical hemolytic uremic syndrome. To the best of our knowledge, there have been no previous reports of an association between diabetic ketoacidosis and atypical hemolytic uremic syndrome. CASE PRESENTATION We describe a case of a 26-year-old Spanish man who presented with diabetic ketoacidosis and was found to have the triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury. The patient had a normal ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity level, and his renal biopsy demonstrated predominant changes of diabetic glomerulosclerosis with an area compatible with thrombotic microangiopathy suggestive of superimposed atypical hemolytic uremic syndrome. Complement sequencing subsequently revealed a potential causative mutation in exon 12 of complement factor B with changes of lysine at amino acid position 533 to an arginine (CFB p.K533R). CONCLUSIONS To the best of our knowledge, this is the first case report of diabetic ketoacidosis presenting with atypical hemolytic uremic syndrome associated with a variant of complement factor B in an adult patient.
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Affiliation(s)
- Ziqiang Zhu
- Department of Internal Medicine, Brookdale University Hospital and Medical Center, One Brookdale Plaza, Brooklyn, NY, 11212, USA.
| | - Hui Chen
- Division of Hematology/Oncology, Brookdale University Hospital and Medical Center, One Brookdale Plaza, Brooklyn, NY, 11212, USA.
| | - Rupinder Gill
- Division of Nephrology, Brookdale University Hospital and Medical Center, One Brookdale Plaza, Brooklyn, NY, 11212, USA.
| | - Jenchin Wang
- Division of Hematology/Oncology, Brookdale University Hospital and Medical Center, One Brookdale Plaza, Brooklyn, NY, 11212, USA.
| | - Samuel Spitalewitz
- Division of Nephrology, Brookdale University Hospital and Medical Center, One Brookdale Plaza, Brooklyn, NY, 11212, USA.
| | - Vladimir Gotlieb
- Division of Hematology/Oncology, Brookdale University Hospital and Medical Center, One Brookdale Plaza, Brooklyn, NY, 11212, USA.
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16
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Muff-Luett M, Nester CM. The Genetics of Ultra-Rare Renal Disease. J Pediatr Genet 2016; 5:33-42. [PMID: 27617140 DOI: 10.1055/s-0036-1572515] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 12/02/2015] [Indexed: 12/14/2022]
Abstract
The complement-mediated renal diseases are a group of ultra-rare renal diseases that disproportionately affect children and young adults and frequently lead to irreversible renal failure. Genetic mutations in alternate pathway of complement genes are pathomechanistically involved in a significant number of these unique diseases. Here, we review our current understanding of the role of genetics in the primary complement-mediated renal diseases affecting children, with a focus on atypical hemolytic uremic syndrome and C3 glomerulopathy. Also, included is a brief discussion of the related diseases whose relationship to complement abnormality has been suspected but not yet confirmed. Advances in genetics have transformed both treatment and outcomes in these historically difficult to treat, highly morbid diseases.
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Affiliation(s)
- Melissa Muff-Luett
- Division of Pediatric Nephrology, University of Nebraska Medical Center, Omaha, Nebraska, United States
| | - Carla M Nester
- Division of Pediatric Nephrology, Dialysis and Transplantation, Stead Family Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States; Molecular Otolaryngology and Renal Research Laboratory, University of Iowa, Iowa City, Iowa, United States
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17
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Davin JC, van de Kar NCAJ. Advances and challenges in the management of complement-mediated thrombotic microangiopathies. Ther Adv Hematol 2015; 6:171-85. [PMID: 26288712 PMCID: PMC4530367 DOI: 10.1177/2040620715577613] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Complement activation plays a major role in several renal pathophysiological conditions. The three pathways of complement lead to C3 activation, followed by the formation of the anaphylatoxin C5a and the terminal membrane attack complex (MAC) in blood and at complement activating surfaces, lead to a cascade of events responsible for inflammation and for the induction of cell lysis. In case of ongoing uncontrolled complement activation, endothelial cells activation takes place, leading to events in which at the end thrombotic microangiopathy can occur. Atypical haemolytic uremic syndrome (aHUS) is a thrombotic microangiopathy characterized by excessive complement activation on the surface of the microcirculation. It is a severe, rare disease which leads to end-stage renal failure (ESRF) and/or to death in more than 50% of patients without treatment. In the first decade of the second millennium, huge progress in understanding the aetiology of this disease was made, which paved the way to better treatment. First, protocols of plasma therapy for treatment, prevention of relapses and for renal transplantation in those patients were set up. Secondly, in some severe cases, combined kidney and liver transplantation was reported. Finally, at the end of this decade, the era of complement inhibitors, as anti-C5 monoclonal antibody (anti-C5 mAb) began. The past five years have seen growing evidence of the favourable effect of anti-C5 mAb in aHUS which has made this drug the first-line treatment in this disease. The possible complication of meningococcal infection needs appropriate vaccination before its use. Unfortunately, the worldwide use of anti-C5 mAb is limited by its very high price. In the future, extension of indications for anti-C5 mAb use, the elaboration of generics and of mAbs directed towards other complement factors of the terminal pathway of the complement system might succeed in reducing the cost of this new valuable therapeutic approach and render it available worldwide for patients from all social classes.
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Affiliation(s)
- Jean-Claude Davin
- Paediatric Nephrology Department, Emma Children's Hospital-Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam Z-O, The Netherlands
| | - Nicole C A J van de Kar
- Department of Paediatric Nephrology, Radboud University Medical Centre, Amalia Children's Hospital, Nijmegen, The Netherlands
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18
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Nester CM, Barbour T, de Cordoba SR, Dragon-Durey MA, Fremeaux-Bacchi V, Goodship THJ, Kavanagh D, Noris M, Pickering M, Sanchez-Corral P, Skerka C, Zipfel P, Smith RJH. Atypical aHUS: State of the art. Mol Immunol 2015; 67:31-42. [PMID: 25843230 DOI: 10.1016/j.molimm.2015.03.246] [Citation(s) in RCA: 191] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/11/2015] [Accepted: 03/12/2015] [Indexed: 12/12/2022]
Abstract
Tremendous advances in our understanding of the thrombotic microangiopathies (TMAs) have revealed distinct disease mechanisms within this heterogeneous group of diseases. As a direct result of this knowledge, both children and adults with complement-mediated TMA now enjoy higher expectations for long-term health. In this update on atypical hemolytic uremic syndrome, we review the clinical characteristics; the genetic and acquired drivers of disease; the broad spectrum of environmental triggers; and current diagnosis and treatment options. Many questions remain to be addressed if additional improvements in patient care and outcome are to be achieved in the coming decade.
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Affiliation(s)
- Carla M Nester
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Division of Nephrology, Stead Family Department of Pediatrics, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Thomas Barbour
- Centre for Complement and Inflammation Research, Department of Medicine, Imperial College, London W12 0NN, UK
| | | | - Marie Agnes Dragon-Durey
- Assistance Publique - Hopitaux de Paris, Service d'Immunologie Biologique, Hopital Europeen Georges Pompidou, Paris, France
| | - Veronique Fremeaux-Bacchi
- Assistance Publique - Hopitaux de Paris, Service d'Immunologie Biologique, Hopital Europeen Georges Pompidou, Paris, France
| | - Tim H J Goodship
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - David Kavanagh
- Assistance Publique - Hopitaux de Paris, Service d'Immunologie Biologique, Hopital Europeen Georges Pompidou, Paris, France
| | - Marina Noris
- IRCCS - Istituto di Ricerche Farmacologiche "Mario Negri", Clinical Research Center for Rare Diseases "Aldo e Cele Daccò", Ranica, Bergamo, Italy
| | - Matthew Pickering
- Centre for Complement and Inflammation Research, Department of Medicine, Imperial College, London W12 0NN, UK
| | - Pilar Sanchez-Corral
- Unidad de Investigación and Ciber de Enfermedades Raras, Hospital Universitario de La Paz_IdiPAZ, Paseo de la Castellana 261, 28046 Madrid, Spain
| | - Christine Skerka
- Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Peter Zipfel
- Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany; Friedrich Schiller University, Jena, Germany
| | - Richard J H Smith
- Molecular Otolaryngology and Renal Research Laboratories, Carver College of Medicine, University of Iowa, Iowa City, IA, USA; Division of Nephrology, Stead Family Department of Pediatrics, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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19
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Alasfar S, Alachkar N. Atypical hemolytic uremic syndrome post-kidney transplantation: two case reports and review of the literature. Front Med (Lausanne) 2014; 1:52. [PMID: 25593925 PMCID: PMC4292050 DOI: 10.3389/fmed.2014.00052] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Accepted: 11/29/2014] [Indexed: 01/09/2023] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare disorder characterized by over-activation and dysregulation of the alternative complement pathway. Its estimated prevalence is 1–2 per million. The disease is characterized by thrombotic microangiopathy, which causes anemia, thrombocytopenia, and acute renal failure. aHUS has more severe course compared to typical (infection-induced) HUS and is frequently characterized by relapses that leads to end stage renal disease. For a long time, kidney transplantation for these patients was contraindicated because of high rate of recurrence and subsequent renal graft loss. The post-kidney transplantation recurrence rate largely depends on the pathogenetic mechanisms involved. However, over the past several years, advancements in the understanding and therapeutics of aHUS have allowed successful kidney transplantation in these patients. Eculizumab, which is a complement C5 antibody that inhibits complement factor 5a and subsequent formation of the membrane-attack complex, has been used in prevention and treatment of post-transplant aHUS recurrence. In this paper, we present two new cases of aHUS patients who underwent successful kidney transplantation in our center with the use of prophylactic and maintenance eculizumab therapy that have not been published before. The purpose of reporting these two cases is to emphasize the importance of using eculizumab as a prophylactic therapy to prevent aHUS recurrence post-transplant in high-risk patients. We will also review the current understanding of the genetics of aHUS, the pathogenesis of its recurrence after kidney transplantation, and strategies for prevention and treatment of post-transplant aHUS recurrence.
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Affiliation(s)
- Sami Alasfar
- Department of Medicine, Division of Nephrology, The Johns Hopkins University School of Medicine , Baltimore, MD , USA
| | - Nada Alachkar
- Department of Medicine, Division of Nephrology, The Johns Hopkins University School of Medicine , Baltimore, MD , USA
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20
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Hanby HA, Zheng XL. Current status in diagnosis and treatment of hereditary thrombotic thrombocytopenic purpura. ACTA ACUST UNITED AC 2014; 3. [PMID: 25343060 DOI: 10.4172/2161-1041.1000e108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hayley A Hanby
- The Cell and Molecular Biology Graduate Group and Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, Tel. 215-590-3565; Fax. 267-426-5165
| | - X Long Zheng
- The Cell and Molecular Biology Graduate Group and Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia and The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, Tel. 215-590-3565; Fax. 267-426-5165
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21
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Yenerel MN. Atypical Hemolytic Uremic Syndrome: Differential Diagnosis from TTP/HUS and Management. Turk J Haematol 2014; 31:216-25. [PMID: 25319590 PMCID: PMC4287021 DOI: 10.4274/tjh.2013.0374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 07/09/2014] [Indexed: 01/17/2023] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a rare form of thrombotic microangiopathy (TMA). It has an unfavorable outcome with death rates as high as 25% during the acute phase and up to 50% of cases progressing to end-stage renal failure. Uncontrolled complement activation through the alternative pathway is thought to be the main underlying pathopysiology of aHUS and corresponds to all the deleterious findings of the disease. Thrombotic thrombocytopenic purpura (TTP) and Shiga toxin-associated HUS are the 2 other important TMA diseases. Although differentiating HUS from TTP is relatively easy in children with a preceding diarrheal illness or invasive S. pneumoniae, differentiating aHUS from TTP or other microangiopathic disorders can present a major diagnostic challenge in adults. ADAMTS13 analysis is currently the most informative diagnostic test for differentiating TTP, congenital TTP, and aHUS. Today empiric plasma therapy still is recommended by expert opinion to be used as early as possible in any patient with symptoms of aHUS. The overall treatment goal remains restoration of a physiological balance between activation and control of the alternative complement pathway. So it is a reasonable approach to block the terminal complement complex with eculizumab in order to prevent further organ injury and increase the likelihood organ recovery. Persistence of hemolysis or lack of improvement of renal function after 3-5 daily plasmaphereses have to be regarded as the major criteria for uncontrolled TMA even if platelet count has normalized and as an indication to switch the treatment to eculizumab. Eculizumab has changed the future perspectives of patients with aHUS and both the FDA and the EMA have approved it as life-long treatment. However, there are still some unresolved issues about the follow-up such as the optimal duration of eculizumab treatment and whether it can be stopped or how to stop the therapy.
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Affiliation(s)
- Mustafa N Yenerel
- İstanbul University İstanbul Faculty of Medicine, Department of Internal Medicine, Division of Hematology, İstanbul, Turkey. E-ma-il:
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22
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Affiliation(s)
- Larry A Greenbaum
- Department of Pediatrics, Emory University and Children's Healthcare of Atlanta, 2015 Uppergate Drive NE, Atlanta, GA 30322, USA.
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23
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Funato M, Uemura O, Ushijima K, Ohnishi H, Orii K, Kato Z, Yamakawa S, Nagai T, Ohara O, Kaneko H, Kondo N. A complement factor B mutation in a large kindred with atypical hemolytic uremic syndrome. J Clin Immunol 2014; 34:691-5. [PMID: 24906628 DOI: 10.1007/s10875-014-0058-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 05/15/2014] [Indexed: 12/12/2022]
Abstract
PURPOSE Gain-of-function mutations in complement factor B (CFB) were recently identified in patients with atypical hemolytic uremic syndrome (aHUS), but are extremely rare. Our purpose is to describe a large kindred with aHUS associated with a CFB mutation and to further understand CFB-mutated aHUS patients. METHODS AND RESULTS We report a large kindred in which 3 members had aHUS. This kindred revealed that 9 of 12 members, including 2 affected patients, had persistent activation of the alternative pathway with low complement component 3 and that those 9 members showed a CFB mutation (c.1050G > C, p.Lys350Asn) in exon 8. This missense mutation was heterozygous in 8 of them and homozygous in only one. From structural studies, this mutation is shown to be located in close proximity to the Mg2-binding site within a von Willebrand factor type A domain of CFB, resulting in a gain-of-function effect of CFB and predisposition to aHUS. At present, 2 of the 3 members with aHUS have maintained normal renal function for a long-term period. CONCLUSIONS This kindred illustrates that a CFB mutation (c.1050G > C, p.Lys350Asn) can result in aHUS. In the future, phenotype-genotype correlations and outcome in CFB-mutated aHUS patients need to be further investigated by accumulation of a number of cases.
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Affiliation(s)
- Michinori Funato
- Department of Pediatrics, Graduate School of Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1194, Japan,
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Abstract
Hemolytic uremic syndrome (HUS) is a triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. The atypical form of HUS is a disease characterized by complement overactivation. Inherited defects in complement genes and acquired autoantibodies against complement regulatory proteins have been described. Incomplete penetrance of mutations in all predisposing genes is reported, suggesting that a precipitating event or trigger is required to unmask the complement regulatory deficiency. The underlying genetic defect predicts the prognosis both in native kidneys and after renal transplantation. The successful trials of the complement inhibitor eculizumab in the treatment of atypical HUS will revolutionize disease management.
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Affiliation(s)
- David Kavanagh
- The Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.
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25
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Marinozzi MC, Vergoz L, Rybkine T, Ngo S, Bettoni S, Pashov A, Cayla M, Tabarin F, Jablonski M, Hue C, Smith RJ, Noris M, Halbwachs-Mecarelli L, Donadelli R, Fremeaux-Bacchi V, Roumenina LT. Complement factor B mutations in atypical hemolytic uremic syndrome-disease-relevant or benign? J Am Soc Nephrol 2014; 25:2053-65. [PMID: 24652797 DOI: 10.1681/asn.2013070796] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Atypical hemolytic uremic syndrome (aHUS) is a genetic ultrarare renal disease associated with overactivation of the alternative pathway of complement. Four gain-of-function mutations that form a hyperactive or deregulated C3 convertase have been identified in Factor B (FB) ligand binding sites. Here, we studied the functional consequences of 10 FB genetic changes recently identified from different aHUS cohorts. Using several tests for alternative C3 and C5 convertase formation and regulation, we identified two gain-of-function and potentially disease-relevant mutations that formed either an overactive convertase (M433I) or a convertase resistant to decay by FH (K298Q). One mutation (R178Q) produced a partially cleaved protein with no ligand binding or functional activity. Seven genetic changes led to near-normal or only slightly reduced ligand binding and functional activity compared with the most common polymorphism at position 7, R7. Notably, none of the algorithms used to predict the disease relevance of FB mutations agreed completely with the experimental data, suggesting that in silico approaches should be undertaken with caution. These data, combined with previously published results, suggest that 9 of 15 FB genetic changes identified in patients with aHUS are unrelated to disease pathogenesis. This study highlights that functional assessment of identified nucleotide changes in FB is mandatory to confirm disease association.
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Affiliation(s)
- Maria Chiara Marinozzi
- Institut National de la Santé et de la Recherche Médicale UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Assistance Publique-Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital Européen Georges Pompidou, Paris, France
| | - Laura Vergoz
- Institut National de la Santé et de la Recherche Médicale UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (Paris-6), Paris, France
| | - Tania Rybkine
- Institut National de la Santé et de la Recherche Médicale UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (Paris-6), Paris, France
| | - Stephanie Ngo
- Assistance Publique-Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital Européen Georges Pompidou, Paris, France
| | - Serena Bettoni
- IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, Ranica, Bergamo, Italy
| | - Anastas Pashov
- Molecular Medicine, Stephan Angelov Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Mathieu Cayla
- Institut National de la Santé et de la Recherche Médicale UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (Paris-6), Paris, France
| | - Fanny Tabarin
- Institut National de la Santé et de la Recherche Médicale UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (Paris-6), Paris, France
| | - Mathieu Jablonski
- Institut National de la Santé et de la Recherche Médicale UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (Paris-6), Paris, France
| | - Christophe Hue
- Institut National de la Santé et de la Recherche Médicale UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (Paris-6), Paris, France
| | - Richard J Smith
- Molecular Otolaryngology and Renal Research Laboratories and Rare Renal Disease Clinic, Departments of Pediatrics and Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Marina Noris
- Laboratory of Immunology and Genetics of Transplantation and Rare Diseases, Mario Negri Institute for Pharmacological Research, Ranica, Bergamo, Italy
| | - Lise Halbwachs-Mecarelli
- Institut National de la Santé et de la Recherche Médicale UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (Paris-6), Paris, France
| | - Roberta Donadelli
- IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Clinical Research Center for Rare Diseases Aldo e Cele Daccò, Ranica, Bergamo, Italy
| | - Veronique Fremeaux-Bacchi
- Institut National de la Santé et de la Recherche Médicale UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, Paris, France; Assistance Publique-Hôpitaux de Paris, Service d'Immunologie Biologique, Hôpital Européen Georges Pompidou, Paris, France
| | - Lubka T Roumenina
- Institut National de la Santé et de la Recherche Médicale UMRS 1138, Cordeliers Research Center, Complement and Diseases Team, Paris, France; Université Paris Descartes Sorbonne Paris-Cité, Paris, France; Université Pierre et Marie Curie (Paris-6), Paris, France;
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26
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Mele C, Remuzzi G, Noris M. Hemolytic uremic syndrome. Semin Immunopathol 2014; 36:399-420. [PMID: 24526222 DOI: 10.1007/s00281-014-0416-x] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 01/19/2014] [Indexed: 12/25/2022]
Abstract
Hemolytic uremic syndrome (HUS) is a thrombotic microangiopathy defined by thrombocytopenia, nonimmune microangiopathic hemolytic anemia, and acute renal failure. The most frequent form is associated with infections by Shiga-like toxin-producing bacteria (STEC-HUS). Rarer cases are triggered by neuraminidase-producing Streptococcus pneumoniae (pneumococcal-HUS). The designation of aHUS is used to refer to those cases in which an infection by Shiga-like toxin-producing bacteria or S. pneumoniae can be excluded. Studies performed in the last two decades have documented that hyperactivation of the complement system is the pathogenetic effector mechanism leading to the endothelial damage and the microvascular thrombosis in aHUS. Recent data suggested the involvement of the complement system in the pathogenesis of STEC-HUS and pneumococcal-HUS as well. Clinical signs and symptoms may overlap among the different forms of HUS; however, pneumococcal-HUS and aHUS have a worse prognosis compared with STEC-HUS. Early diagnosis and identification of underlying pathogenetic mechanism allows instating specific support measures and therapies. In clinical trials in patients with aHUS, complement inhibition by eculizumab administration leads to a rapid and sustained normalization of hematological parameters with improvement in long-term renal function. This review summarizes current concepts about the epidemiological findings, the pathological and clinical aspects of STEC-HUS, pneumococcal-HUS, and aHUS, and their diagnosis and management.
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Affiliation(s)
- Caterina Mele
- IRCCS Istituto di Ricerche Farmacologiche "Mario Negri", Clinical Research Center for Rare Diseases "Aldo e Cele Daccò", Via Camozzi, 3, Ranica, Bergamo, 24020, Italy
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27
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Subfractionation, characterization, and in-depth proteomic analysis of glomerular membrane vesicles in human urine. Kidney Int 2013; 85:1225-37. [PMID: 24196483 PMCID: PMC4008663 DOI: 10.1038/ki.2013.422] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 08/26/2013] [Accepted: 08/29/2013] [Indexed: 01/15/2023]
Abstract
Urinary exosome-like vesicles (ELVs) are a heterogenous mixture (diameter 40–200nm) containing vesicles shed from all segments of the nephron including glomerular podocytes. Contamination with Tamm Horsfall protein (THP) oligomers has hampered their isolation and proteomic analysis. Here we improved ELV isolation protocols employing density centrifugation to remove THP and albumin, and isolated a glomerular membranous vesicle (GMV) enriched subfraction from 7 individuals identifying 1830 proteins and in 3 patients with glomerular disease identifying 5657 unique proteins. The GMV fraction was composed of podocin/podocalyxin positive irregularly shaped membranous vesicles and podocin/podocalyxin negative classical exosomes. Ingenuity pathway analysis identified integrin, actin cytoskeleton and RhoGDI signaling in the top three canonical represented signaling pathways and 19 other proteins associated with inherited glomerular diseases. The GMVs are of podocyte origin and the density gradient technique allowed isolation in a reproducible manner. We show many nephrotic syndrome proteins, proteases and complement proteins involved in glomerular disease are in GMVs and some were shed in the disease state (nephrin, TRPC6 and INF2 and PLA2R). We calculated sample sizes required to identify new glomerular disease biomarkers, expand the ELV proteome and provide a reference proteome in a database that may prove useful in the search for biomarkers of glomerular disease.
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Salvadori M, Bertoni E. Update on hemolytic uremic syndrome: Diagnostic and therapeutic recommendations. World J Nephrol 2013; 2:56-76. [PMID: 24255888 PMCID: PMC3832913 DOI: 10.5527/wjn.v2.i3.56] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 06/26/2013] [Accepted: 08/13/2013] [Indexed: 02/06/2023] Open
Abstract
Hemolytic uremic syndrome (HUS) is a rare disease. In this work the authors review the recent findings on HUS, considering the different etiologic and pathogenetic classifications. New findings in genetics and, in particular, mutations of genes that encode the complement-regulatory proteins have improved our understanding of atypical HUS. Similarly, the complement proteins are clearly involved in all types of thrombotic microangiopathy: typical HUS, atypical HUS and thrombotic thrombocytopenic purpura (TTP). Furthermore, several secondary HUS appear to be related to abnormalities in complement genes in predisposed patients. The authors highlight the therapeutic aspects of this rare disease, examining both “traditional therapy” (including plasma therapy, kidney and kidney-liver transplantation) and “new therapies”. The latter include anti-Shiga-toxin antibodies and anti-C5 monoclonal antibody “eculizumab”. Eculizumab has been recently launched for the treatment of the atypical HUS, but it appears to be effective in the treatment of typical HUS and in TTP. Future therapies are in phases I and II. They include anti-C5 antibodies, which are more purified, less immunogenic and absorbed orally and, anti-C3 antibodies, which are more powerful, but potentially less safe. Additionally, infusions of recombinant complement-regulatory proteins are a potential future therapy.
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Wong EKS, Goodship THJ, Kavanagh D. Complement therapy in atypical haemolytic uraemic syndrome (aHUS). Mol Immunol 2013; 56:199-212. [PMID: 23810412 PMCID: PMC3899040 DOI: 10.1016/j.molimm.2013.05.224] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Accepted: 05/10/2013] [Indexed: 12/22/2022]
Abstract
Central to the pathogenesis of atypical haemolytic uraemic syndrome (aHUS) is over-activation of the alternative pathway of complement. Inherited defects in complement genes and autoantibodies against complement regulatory proteins have been described. The use of plasma exchange to replace non-functioning complement regulators and hyper-functional complement components in addition to the removal of CFH-autoantibodies made this the ‘gold-standard’ for management of aHUS. In the last 4 years the introduction of the complement inhibitor Eculizumab has revolutionised the management of aHUS. In this review we shall discuss the available literature on treatment strategies to date.
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Affiliation(s)
- Edwin K S Wong
- The Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
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Association of CFH and CFB gene polymorphisms with retinopathy in type 2 diabetic patients. Mediators Inflamm 2013; 2013:748435. [PMID: 23864767 PMCID: PMC3707223 DOI: 10.1155/2013/748435] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 06/02/2013] [Accepted: 06/10/2013] [Indexed: 12/21/2022] Open
Abstract
Objectives. The complement system is a key component of innate immunity and has been implicated in the pathogenesis of diabetic retinopathy (DR). This study aimed at investigating whether polymorphisms of two genes in the complement pathway, complement factor H (CFH) and complement factor B (CFB), are associated with DR. Methods. 552 well-defined subjects with type 2 diabetes, consisting of 277 DR patients and 275 diabetic controls, were recruited. Four Tag-SNPs rs1048709, rs537160, rs4151657, and rs2072633 in CFB and rs800292 (I62V) in CFH were examined using TaqMan Genotyping Assays. Results. There were significant increases in the frequencies of A allele and AA genotype for rs1048709 in DR patients compared with diabetic controls (Pcorr = 0.035, OR = 1.42; Pcorr = 0.02, OR = 2.27, resp.): meanwhile, significant decreases in the frequencies of A allele and AA genotype for rs800292 were observed in DR patients compared with diabetic controls (Pcorr = 0.04, OR = 0.72; Pcorr = 0.015, OR = 0.51, resp.). Joint effect of these two loci was also identified. Moreover, rs800292/AA genotype was found to be related with delayed progression to DR. Conclusions. CFH-rs800292 and CFB-rs1048709 are associated with the presence of DR, which strengthens the concept that complement system plays an important role in the pathogenesis of DR.
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Eculizumab in the treatment of atypical haemolytic uraemic syndrome and other complement-mediated renal diseases. Curr Opin Pediatr 2013; 25:225-31. [PMID: 23486421 DOI: 10.1097/mop.0b013e32835df4a3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW This review considers the use of eculizumab in the treatment of atypical haemolytic uraemic syndrome (aHUS) as well as the other complement-mediated renal diseases, including dense deposit disease (DDD) and C3 glomerulonephritis (C3GN). In addition, a brief discussion of the effectiveness of eculizumab for the prevention of antibody-mediated rejection (AMR) in the setting of renal transplant and the treatment of shiga toxin associated haemolytic uraemic syndrome (STEC HUS) is also provided. RECENT FINDINGS No randomized controlled trials exist to support the use of eculizumab in renal disease. The results of two unpublished, prospective adult and adolescent trials support its utility in aHUS, whereas retrospective data support the effectiveness in paediatric aHUS. These two data sets form the basis of the sole renal indication for eculizumab. One small, single-centre trial and a growing number of case reports support the use of eculizumab in C3 glomerulopathy (C3G). There are limited trial data in AMR and renal transplant. Finally, there are conflicting data for the use of eculizumab in STEC HUS. SUMMARY The cumulative published data establish the effectiveness of eculizumab in a select group of renal diseases that have at the centre of their disease either abnormal complement control or maladaptive complement activation.
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Abstract
Hemolytic uremic syndrome (HUS) is defined by the triad of mechanical hemolytic anemia, thrombocytopenia and renal impairment. Atypical HUS (aHUS) defines non Shiga-toxin-HUS and even if some authors include secondary aHUS due to Streptococcus pneumoniae or other causes, aHUS designates a primary disease due to a disorder in complement alternative pathway regulation. Atypical HUS represents 5 -10% of HUS in children, but the majority of HUS in adults. The incidence of complement-aHUS is not known precisely. However, more than 1000 aHUS patients investigated for complement abnormalities have been reported. Onset is from the neonatal period to the adult age. Most patients present with hemolytic anemia, thrombocytopenia and renal failure and 20% have extra renal manifestations. Two to 10% die and one third progress to end-stage renal failure at first episode. Half of patients have relapses. Mutations in the genes encoding complement regulatory proteins factor H, membrane cofactor protein (MCP), factor I or thrombomodulin have been demonstrated in 20-30%, 5-15%, 4-10% and 3-5% of patients respectively, and mutations in the genes of C3 convertase proteins, C3 and factor B, in 2-10% and 1-4%. In addition, 6-10% of patients have anti-factor H antibodies. Diagnosis of aHUS relies on 1) No associated disease 2) No criteria for Shigatoxin-HUS (stool culture and PCR for Shiga-toxins; serology for anti-lipopolysaccharides antibodies) 3) No criteria for thrombotic thrombocytopenic purpura (serum ADAMTS 13 activity > 10%). Investigation of the complement system is required (C3, C4, factor H and factor I plasma concentration, MCP expression on leukocytes and anti-factor H antibodies; genetic screening to identify risk factors). The disease is familial in approximately 20% of pedigrees, with an autosomal recessive or dominant mode of transmission. As penetrance of the disease is 50%, genetic counseling is difficult. Plasmatherapy has been first line treatment until presently, without unquestionable demonstration of efficiency. There is a high risk of post-transplant recurrence, except in MCP-HUS. Case reports and two phase II trials show an impressive efficacy of the complement C5 blocker eculizumab, suggesting it will be the next standard of care. Except for patients treated by intensive plasmatherapy or eculizumab, the worst prognosis is in factor H-HUS, as mortality can reach 20% and 50% of survivors do not recover renal function. Half of factor I-HUS progress to end-stage renal failure. Conversely, most patients with MCP-HUS have preserved renal function. Anti-factor H antibodies-HUS has favourable outcome if treated early.
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Affiliation(s)
- Chantal Loirat
- Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Université Paris VII, Pediatric Nephrology Department, Paris, France.
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Abstract
Hemolytic uremic syndrome (HUS) is defined by the triad of mechanical hemolytic anemia, thrombocytopenia and renal impairment. Atypical HUS (aHUS) defines non Shiga-toxin-HUS and even if some authors include secondary aHUS due to Streptococcus pneumoniae or other causes, aHUS designates a primary disease due to a disorder in complement alternative pathway regulation. Atypical HUS represents 5 -10% of HUS in children, but the majority of HUS in adults. The incidence of complement-aHUS is not known precisely. However, more than 1000 aHUS patients investigated for complement abnormalities have been reported. Onset is from the neonatal period to the adult age. Most patients present with hemolytic anemia, thrombocytopenia and renal failure and 20% have extra renal manifestations. Two to 10% die and one third progress to end-stage renal failure at first episode. Half of patients have relapses. Mutations in the genes encoding complement regulatory proteins factor H, membrane cofactor protein (MCP), factor I or thrombomodulin have been demonstrated in 20-30%, 5-15%, 4-10% and 3-5% of patients respectively, and mutations in the genes of C3 convertase proteins, C3 and factor B, in 2-10% and 1-4%. In addition, 6-10% of patients have anti-factor H antibodies. Diagnosis of aHUS relies on 1) No associated disease 2) No criteria for Shigatoxin-HUS (stool culture and PCR for Shiga-toxins; serology for anti-lipopolysaccharides antibodies) 3) No criteria for thrombotic thrombocytopenic purpura (serum ADAMTS 13 activity > 10%). Investigation of the complement system is required (C3, C4, factor H and factor I plasma concentration, MCP expression on leukocytes and anti-factor H antibodies; genetic screening to identify risk factors). The disease is familial in approximately 20% of pedigrees, with an autosomal recessive or dominant mode of transmission. As penetrance of the disease is 50%, genetic counseling is difficult. Plasmatherapy has been first line treatment until presently, without unquestionable demonstration of efficiency. There is a high risk of post-transplant recurrence, except in MCP-HUS. Case reports and two phase II trials show an impressive efficacy of the complement C5 blocker eculizumab, suggesting it will be the next standard of care. Except for patients treated by intensive plasmatherapy or eculizumab, the worst prognosis is in factor H-HUS, as mortality can reach 20% and 50% of survivors do not recover renal function. Half of factor I-HUS progress to end-stage renal failure. Conversely, most patients with MCP-HUS have preserved renal function. Anti-factor H antibodies-HUS has favourable outcome if treated early.
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Abrera-Abeleda MA, Nishimura C, Frees K, Jones M, Maga T, Katz LM, Zhang Y, Smith RJH. Allelic variants of complement genes associated with dense deposit disease. J Am Soc Nephrol 2011; 22:1551-9. [PMID: 21784901 DOI: 10.1681/asn.2010080795] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The alternative pathway of the complement cascade plays a role in the pathogenesis of dense deposit disease (DDD). Deficiency of complement factor H and mutations in CFH associate with the development of DDD, but it is unknown whether allelic variants in other complement genes also associate with this disease. We studied patients with DDD and identified previously unreported sequence alterations in several genes in addition to allelic variants and haplotypes common to patients with DDD. We found that the likelihood of developing DDD increases with the presence of two or more risk alleles in CFH and C3. To determine the functional consequence of this finding, we measured the activity of the alternative pathway in serum samples from phenotypically normal controls genotyped for variants in CFH and C3. Alternative pathway activity was higher in the presence of variants associated with DDD. Taken together, these data confirm that DDD is a complex genetic disease and may provide targets for the development of disease-specific therapies.
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Nester C, Stewart Z, Myers D, Jetton J, Nair R, Reed A, Thomas C, Smith R, Brophy P. Pre-emptive eculizumab and plasmapheresis for renal transplant in atypical hemolytic uremic syndrome. Clin J Am Soc Nephrol 2011; 6:1488-94. [PMID: 21617085 DOI: 10.2215/cjn.10181110] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The case of a 12-year-old with a hybrid CFH/CFHL1 gene and atypical hemolytic uremic syndrome (aHUS) that had previously developed native kidney and then renal allograft loss is reported. This case illustrates the relatively common occurrence of renal loss from the late presentation of aHUS. Also presented is a protocol for the pre-emptive use of eculizumab and plasmapheresis as part of a renal transplant plan for the treatment of aHUS in patients deemed at high risk for recurrent disease. This protocol was a result of a multidisciplinary approach including adult and pediatric nephrology, transplant surgery, transfusion medicine, and infectious disease specialists. This protocol and the justifications and components of it can function as a guideline for the treatment of a group of children that have waited in limbo for the first U.S. transplant to open the door to this type of definitive care for this devastating disease.
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Affiliation(s)
- Carla Nester
- Department of Pediatrics, University of Iowa, Iowa City, Iowa 52242, USA.
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Abstract
Complement is a part of the body's innate immune system that helps defend the host from microbial infection. It is tightly controlled by a number of cell surface and fluid-phase proteins so that under normal circumstances injury to autologous tissues is avoided. In many pathological settings, such as when the complement regulatory mechanisms are dysfunctional or overwhelmed, complement attack of autologous tissues can occur with severe, sometimes life-threatening consequences. The kidney appears to be particularly vulnerable to complement-mediated inflammatory injury and many kidney pathologies have been linked to abnormal complement activation. Clinical and experimental studies have shown that complement attack can be a primary cause in rare, genetically predisposed kidney diseases or a significant contributor to kidney injury caused by other etiological factors. Here we provide a brief review of recent advances on the activation and regulation of the complement system in kidney disease, with a particular emphasis on the relevance of complement regulatory proteins.
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Affiliation(s)
- Allison M Lesher
- Institute for Translational Medicine and Therapeutics and Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
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Sánchez-Corral P, Melgosa M. Advances in understanding the aetiology of atypical Haemolytic Uraemic Syndrome. Br J Haematol 2010; 150:529-42. [PMID: 20629662 DOI: 10.1111/j.1365-2141.2010.08295.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Atypical Haemolytic Uraemic Syndrome (aHUS) is a thrombotic microangiopathy that often provokes irreversible renal damage and post-transplantation recurrence. Studies performed during the last decade have shown that 50-60% of aHUS patients present genetic or acquired defects in the complement system that enhance the initial endothelial damage and favour disease development. This review analyses the complement proteins and processes that are disturbed in aHUS patients, and outlines the relevance of a prompt genetic/molecular diagnosis for improving clinical management and prognosis.
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