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Abstract
The complement system consists of three pathways (alternative, classical, and lectin) that play a fundamental role in immunity and homeostasis. The multifunctional role of the complement system includes direct lysis of pathogens, tagging pathogens for phagocytosis, promotion of inflammatory responses to control infection, regulation of adaptive cellular immune responses, and removal of apoptotic/dead cells and immune complexes from circulation. A tight regulation of the complement system is essential to avoid unwanted complement-mediated damage to the host. This regulation is ensured by a set of proteins called complement regulatory proteins. Deficiencies or malfunction of these regulatory proteins may lead to pro-thrombotic hematological diseases, renal and ocular diseases, and autoimmune diseases, among others. This review focuses on the importance of two complement regulatory proteins of the alternative pathway, Factor H and properdin, and their role in human diseases with an emphasis on: (a) characterizing the main mechanism of action of Factor H and properdin in regulating the complement system and protecting the host from complement-mediated attack, (b) describing the dysregulation of the alternative pathway as a result of deficiencies, or mutations, in Factor H and properdin, (c) outlining the clinical findings, management and treatment of diseases associated with mutations and deficiencies in Factor H, and (d) defining the unwanted and inadequate functioning of properdin in disease, through a discussion of various experimental research findings utilizing in vitro, mouse and human models.
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Affiliation(s)
- Claudio Cortes
- Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, MI, United States.
| | - Caroline Desler
- Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Amanda Mazzoli
- Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Jin Y Chen
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States.
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Malinina DA, Shlyk IV, Polushin YS, Аfanasiev AA, Stanevich OV, Bakin EA. The informative value of proadrenomedullin in patients with severe COVID-19. Vestn anesteziol reanimatol 2020. [DOI: 10.21292/2078-5658-2020-17-6-31-38] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | - I. V. Shlyk
- Pavlov First Saint Petersburg State Medical University
| | | | | | - O. V. Stanevich
- Pavlov First Saint Petersburg State Medical University; Smorodintsev Research Institute of Influenza
| | - E. A. Bakin
- Pavlov First Saint Petersburg State Medical University
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3
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Karakioulaki M, Stolz D. Biomarkers in Pneumonia-Beyond Procalcitonin. Int J Mol Sci 2019; 20:E2004. [PMID: 31022834 DOI: 10.3390/ijms20082004] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 04/21/2019] [Accepted: 04/22/2019] [Indexed: 01/10/2023] Open
Abstract
Pneumonia is the leading infectious cause of mortality worldwide and one of the most common lower respiratory tract infections that is contributing significantly to the burden of antibiotic consumption. Due to the complexity of its pathophysiology, it is widely accepted that clinical diagnosis and prognosis are inadequate for the accurate assessment of the severity of the disease. The most challenging task for a physician is the risk stratification of patients with community-acquired pneumonia. Herein, early diagnosis is essential in order to reduce hospitalization and mortality. Procalcitonin and C-reactive protein remain the most widely used biomarkers, while interleukin 6 has been of particular interest in the literature. However, none of them appear to be ideal, and the search for novel biomarkers that will most sufficiently predict the severity and treatment response in pneumonia has lately intensified. Although our insight has significantly increased over the last years, a translational approach with the application of genomics, metabolomics, microbiomics, and proteomics is required to better understand the disease. In this review, we discuss this rapidly evolving area and summarize the application of novel biomarkers that appear to be promising for the accurate diagnosis and risk stratification of pneumonia.
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Morley D, Torres A, Cillóniz C, Martin-Loeches I. Predictors of treatment failure and clinical stability in patients with community acquired pneumonia. Ann Transl Med 2017; 5:443. [PMID: 29264360 DOI: 10.21037/atm.2017.06.54] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Community acquired pneumonia (CAP) is the leading infectious cause of mortality worldwide with approximately 10% of patients hospitalized requiring intensive care unit (ICU) admission. The ability to predict clinical stability (CS) and treatment failure (TF) enables the clinician to alter antibiotics appropriately, facilitate a timely ICU admission, or arrange a suitable discharge. The detection of CS and TF can be difficult and changes in clinical signs may be subtle or delayed. Thus clinical scores and biomarkers are routinely used to identify severity and monitor clinical progression. The evidence, however, is vast and the definitive role of these systems is at times difficult to elucidate. The aim of this review is to analyse the current literature and to provide a rational and clinically focused view of the predictive utility of various systems used to identify CS and TF in CAP.
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Affiliation(s)
- Deirdre Morley
- Multidisciplinary Intensive Care Research Organization (MICRO), St James's University Hospital, Dublin, Ireland
| | - Antoni Torres
- Department of Pneumology, Hospital Clinic Barcelona, Universidad Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica En Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Catia Cillóniz
- Department of Pneumology, Hospital Clinic Barcelona, Universidad Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica En Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Ignacio Martin-Loeches
- Multidisciplinary Intensive Care Research Organization (MICRO), St James's University Hospital, Dublin, Ireland.,Department of Clinical Medicine, Trinity Centre for Health Sciences, Dublin, Ireland
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Sim RB, Ferluga J, Al-Rashidi H, Abbow H, Schwaeble W, Kishore U. Complement factor H in its alternative identity as adrenomedullin-binding protein 1. Mol Immunol 2016; 68:45-8. [PMID: 26597206 DOI: 10.1016/j.molimm.2015.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 06/07/2015] [Indexed: 11/16/2022]
Abstract
Complement factor H has been extensively studied since its discovery 50 years ago, and its role in the complement system is quite well established. It has another role, however, as a binding protein for the regulatory peptide adrenomedullin. Part of this role appears to be protection of adrenomedullin from proteolytic degradation. The binding interaction is unusual and merits further investigation. Adrenomedullin has potential therapeutic uses in diseases affecting the vasculature, and factor H has been administered with adrenomedullin in some animal models of disease.
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Affiliation(s)
- Robert B Sim
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK; Department of Infection, Immunity and Inflammation, University of Leicester, University Rd, Leicester, LE1 9HN, UK.
| | - Janez Ferluga
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford OX1 3QU, UK; Centre for Infection, Immunity and Disease Mechanisms, Biosciences, Heinz Wolff Building, Brunel University, London UB8 3PH, UK
| | - Hanan Al-Rashidi
- Department of Infection, Immunity and Inflammation, University of Leicester, University Rd, Leicester, LE1 9HN, UK
| | - Hussein Abbow
- Department of Infection, Immunity and Inflammation, University of Leicester, University Rd, Leicester, LE1 9HN, UK
| | - Wilhelm Schwaeble
- Department of Infection, Immunity and Inflammation, University of Leicester, University Rd, Leicester, LE1 9HN, UK
| | - Uday Kishore
- Centre for Infection, Immunity and Disease Mechanisms, Biosciences, Heinz Wolff Building, Brunel University, London UB8 3PH, UK
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Kopp A, Hebecker M, Svobodová E, Józsi M. Factor h: a complement regulator in health and disease, and a mediator of cellular interactions. Biomolecules 2012; 2:46-75. [PMID: 24970127 PMCID: PMC4030870 DOI: 10.3390/biom2010046] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 01/23/2012] [Accepted: 01/26/2012] [Indexed: 12/12/2022] Open
Abstract
Complement is an essential part of innate immunity as it participates in host defense against infections, disposal of cellular debris and apoptotic cells, inflammatory processes and modulation of adaptive immune responses. Several soluble and membrane-bound regulators protect the host from the potentially deleterious effects of uncontrolled and misdirected complement activation. Factor H is a major soluble regulator of the alternative complement pathway, but it can also bind to host cells and tissues, protecting them from complement attack. Interactions of factor H with various endogenous ligands, such as pentraxins, extracellular matrix proteins and DNA are important in limiting local complement-mediated inflammation. Impaired regulatory as well as ligand and cell recognition functions of factor H, caused by mutations or autoantibodies, are associated with the kidney diseases: atypical hemolytic uremic syndrome and dense deposit disease and the eye disorder: age-related macular degeneration. In addition, factor H binds to receptors on host cells and is involved in adhesion, phagocytosis and modulation of cell activation. In this review we discuss current concepts on the physiological and pathophysiological roles of factor H in light of new data and recent developments in our understanding of the versatile roles of factor H as an inhibitor of complement activation and inflammation, as well as a mediator of cellular interactions. A detailed knowledge of the functions of factor H in health and disease is expected to unravel novel therapeutic intervention possibilities and to facilitate the development or improvement of therapies.
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Affiliation(s)
- Anne Kopp
- Junior Research Group Cellular Immunobiology, Leibniz Institute for Natural Product Research and Infection Biology, Jena 07745, Germany.
| | - Mario Hebecker
- Junior Research Group Cellular Immunobiology, Leibniz Institute for Natural Product Research and Infection Biology, Jena 07745, Germany.
| | - Eliška Svobodová
- Junior Research Group Cellular Immunobiology, Leibniz Institute for Natural Product Research and Infection Biology, Jena 07745, Germany.
| | - Mihály Józsi
- Junior Research Group Cellular Immunobiology, Leibniz Institute for Natural Product Research and Infection Biology, Jena 07745, Germany.
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Miguel D, Prieto B, Costa M, Coto D, Alvarez FV. Cord blood plasma reference intervals for potential sepsis markers: pro-adrenomedullin, pro-endothelin, and pro-atrial natriuretic peptide. Clin Biochem 2011; 44:337-41. [PMID: 21211519 DOI: 10.1016/j.clinbiochem.2010.12.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 12/15/2010] [Accepted: 12/18/2010] [Indexed: 01/30/2023]
Abstract
OBJECTIVES To establish reference values in cord blood of the following new sepsis markers: pro-adrenomedullin (MR-proADM), pro-endothelin (CT-proET-1), and pro-atrial natriuretic peptide (MR-proANP). METHODS MR-proADM, CT-proET-1, MR-proANP, and procalcitonin (PCT) were measured in cord blood of newborn infants by Time Resolved Amplified Cryptate Emission (TRACE) technology. The inclusion criteria in the control group (n=194) was the absence of any clinical sign or risk factor of sepsis. A group of 73 newborn infants presenting with risk factors of sepsis at delivery was also studied. RESULTS The median values (reference interval) of CT-proET-1, MR-pro-ADM, and MR-proANP measured in cord blood plasma were 72 pmol/L (39-115), 0.84 nmol/L (0.5-1.38), and 163 pmol/L (76-389), respectively. The PCT reference interval was not significantly different from that previously described in cord blood serum. CONCLUSIONS The reference intervals established will serve as a starting point for further clinical investigations aimed to elucidate the potential prognostic/diagnostic value of these markers in neonatal sepsis management.
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Abstract
The complement system is an essential component of the innate immune system that participates in elimination of pathogens and altered host cells and comprises an essential link between the innate and adaptive immune system. Soluble and membrane-bound complement regulators protect cells and tissues from unintended complement-mediated injury. Complement factor H is a soluble complement regulator essential for controlling the alternative pathway in blood and on cell surfaces. Normal recognition of self-cell markers (i.e. polyanions) and C3b/C3d fragments is necessary for factor H function. Inadequate recognition of host cell surfaces by factor H due to mutations and polymorphisms have been associated with complement-mediated tissue damage and disease. On the other hand, unwanted recognition of pathogens and altered self-cells (i.e. cancer) by factor H is used as an immune evasion strategy. This review will focus on the current knowledge related to these versatile recognition properties of factor H.
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Affiliation(s)
- Viviana P Ferreira
- Department of Medical Microbiology and Immunology, College of Medicine, University of Toledo, Toledo, OH 43614, United States.
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Jacob A, Zhou M, Wu R, Halpern VJ, Ravikumar TS, Wang P. Pro-inflammatory cytokines from Kupffer cells downregulate hepatocyte expression of adrenomedullin binding protein-1. Biochim Biophys Acta Mol Basis Dis 2007; 1772:766-72. [PMID: 17490866 PMCID: PMC2440713 DOI: 10.1016/j.bbadis.2007.03.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Revised: 03/29/2007] [Accepted: 03/30/2007] [Indexed: 11/19/2022]
Abstract
Polymicrobial sepsis is characterized by an early, hyperdynamic phase followed by a late hypodynamic phase. Adrenomedullin (AM), a vasodilatory peptide, inhibits this transition from the early phase to the late phase. Adrenomedullin binding protein-1 (AMBP-1) enhances AM-mediated activities. The decrease of AMBP-1 levels in late sepsis reduces the vascular response to AM and produces the hypodynamic phase. Studies have indicated that the administration of LPS downregulates AMBP-1 production in the liver. Since hepatocytes are the primary source of AMBP-1 biosynthesis in the liver, we employed a co-culture strategy using hepatocyte and Kupffer cells to determine whether LPS directly or by increasing pro-inflammatory cytokines from Kupffer cells downregulates AMBP-1 production. Hepatocytes and Kupffer cells isolated from rats were co-cultured and treated with LPS for 24 h. LPS significantly attenuated AMBP-1 protein expression in a dose-dependent manner. Since AMBP-1 is basically a secretory protein, cell supernatants from co-culture cells treated with LPS were examined for AMBP-1 protein levels. LPS treatment caused a dose related decrease in AMBP-1 protein secretion. Similarly, LPS treatment produced a significant decrease in AMBP-1 protein expression in hepatocytes and Kupffer cells cultured using transwell inserts. LPS had no direct effect on AMBP-1 levels in cultured hepatocytes or Kupffer cells alone. To confirm that the observed effects in co-culture were due to the cytokines released from Kupffer cells, hepatocytes were treated with IL-1beta or TNF-alpha for 24 h and AMBP-1 expression was examined. The results indicated that both cytokines significantly inhibited AMBP-1 protein levels. Thus, pro-inflammatory cytokines released from Kupffer cells are responsible for downregulation of AMBP-1.
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Affiliation(s)
- Asha Jacob
- Department of Surgery, North Shore University Hospital and Long Island Jewish Medical Center, Manhasset, NY 11030, USA
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Christ-Crain M, Morgenthaler NG, Stolz D, Müller C, Bingisser R, Harbarth S, Tamm M, Struck J, Bergmann A, Müller B. Pro-adrenomedullin to predict severity and outcome in community-acquired pneumonia [ISRCTN04176397]. Crit Care 2006; 10:R96. [PMID: 16805922 PMCID: PMC1550935 DOI: 10.1186/cc4955] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2006] [Accepted: 05/22/2006] [Indexed: 01/22/2023]
Abstract
Introduction Pro-adrenomedullin (proADM) is helpful for individual risk assessment and outcome prediction in sepsis. A major cause of sepsis is community-acquired pneumonia (CAP). The aim of this study was to investigate the value of proADM levels for severity assessment and outcome prediction in CAP. Methods Data from 302 patients admitted to the emergency department with CAP were included in a prospective observational study. Procalcitonin, C-reactive protein levels, leukocyte count, clinical variables and the pneumonia severity index (PSI) were measured. ProADM levels were measured with a new sandwich immunoassay for mid regional ProADM (MR-proADM, Brahms AG, Hennigsdorf/Berlin, Germany). Results ProADM levels, in contrast to C-reactive protein and leukocyte count, increased with increasing severity of CAP, classified according to the PSI score (ANOVA, p < 0.001). In patients who died during follow-up, proADM levels on admission were significantly higher compared to levels in survivors (2.1 (1.5 to 3.0) versus 1.0 (0.6 to 1.6) nmol/l, p < 0.001). In a receiver operating characteristic (ROC) analysis for survival, the area under the ROC curve (AUC) for proADM was 0.76 (95% confidence interval (CI) 0.71–0.81), which was significantly higher compared to procalcitonin (p = 0.004), C-reactive protein (p < 0.001) and total leukocyte count (p = 0.001) and similar to the AUC of the PSI (0.73, p = 0.54). A clinical model including the PSI and proADM increased the prognostic accuracy to predict failure compared to a model relying on the PSI alone (AUC, 0.77 (0.70 to 0.84), p = 0.03). Conclusion ProADM, as a novel biomarker, is a useful tool for the risk stratification of patients with CAP.
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Affiliation(s)
| | | | - Daiana Stolz
- Department of Pneumology, University Hospital Basel, Switzerland
| | - Christian Müller
- Department of Internal Medicine, University Hospital Basel, Switzerland
| | - Roland Bingisser
- Department of Internal Medicine, University Hospital Basel, Switzerland
| | | | - Michael Tamm
- Department of Pneumology, University Hospital Basel, Switzerland
| | | | | | - Beat Müller
- Department of Internal Medicine, University Hospital Basel, Switzerland
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Christ-Crain M, Morgenthaler NG, Struck J, Harbarth S, Bergmann A, Müller B. Mid-regional pro-adrenomedullin as a prognostic marker in sepsis: an observational study. Crit Care 2005; 9:R816-24. [PMID: 16356231 PMCID: PMC1414007 DOI: 10.1186/cc3885] [Citation(s) in RCA: 210] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 09/22/2005] [Accepted: 09/29/2005] [Indexed: 02/07/2023]
Abstract
Introduction Measurement of biomarkers is a potential approach to early assessment and prediction of mortality in patients with sepsis. The aim of the present study was to evaluate the prognostic value of mid-regional pro-adrenomedullin (MR-proADM) levels in a cohort of medical intensive care patients and to compare it with other biomarkers and physiological scores. Method We evaluated blood samples from 101 consecutive critically ill patients admitted to the intensive care unit and from 160 age-matched healthy control individuals. The patients had initially been enrolled in a prospective observational study investigating the prognostic value of endocrine dysfunction in critically ill patients ("PEDCRIP" Study). The prognostic value of MR-proADM levels was compared with those of two physiological scores and of various biomarkers (for example C-reactive Protein, IL-6, procalcitonin). MR-proADM was measured in EDTA plasma from all patients using a new sandwich immunoassay. Results On admission, 53 patients had sepsis, severe sepsis, or septic shock, and 48 had systemic inflammatory response syndrome. Median MR-proADM levels on admission (nmol/l [range]) were 1.1 (0.3–3.7) in patients with systemic inflammatory response syndrome, 1.8 (0.4–5.8) in those with sepsis, 2.3 (1.0–17.6) in those with severe sepsis and 4.5 (0.9–21) in patients with septic shock. In healthy control individuals the median MR-proADM was 0.4 (0.21–0.97). On admission, circulating MR-proADM levels in patients with sepsis, severe sepsis, or septic shock were significantly higher in nonsurvivors (8.5 [0.8–21.0]; P < 0.001) than in survivors (1.7 [0.4–17.6]). In a receiver operating curve analysis of survival of patients with sepsis, the area under the curve (AUC) for MR-proADM was 0.81, which was similar to the AUCs for IL-6, Acute Physiology and Chronic Health Evaluation II score and Simplified Acute Physiology Score II. The prognostic value of MR-proADM was independent of the sepsis classification system used. Conclusion MR-proADM may be helpful in individual risk assessment in septic patients.
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Affiliation(s)
- Mirjam Christ-Crain
- Department of Internal Medicine, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland
| | - Nils G Morgenthaler
- Research Department, Brahms AG, Hennigsdorf/Berlin, Neuendorfstrasse 25, 16761 Hennigsdorf, Germany
| | - Joachim Struck
- Research Department, Brahms AG, Hennigsdorf/Berlin, Neuendorfstrasse 25, 16761 Hennigsdorf, Germany
| | - Stephan Harbarth
- Division of Hospital Epidemiology, University Hospital Geneva, 24, rue Micheli-du-Crest, 1211 Geneva 14, Switzerland
| | - Andreas Bergmann
- Research Department, Brahms AG, Hennigsdorf/Berlin, Neuendorfstrasse 25, 16761 Hennigsdorf, Germany
| | - Beat Müller
- Department of Internal Medicine, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland
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Guigonis V, Frémeaux-Bacchi V, Giraudier S, Favier R, Borderie D, Massy Z, Mougenot B, Rosenblatt DS, Deschênes G. Late-onset thrombocytic microangiopathy caused by cblC disease: association with a factor H mutation. Am J Kidney Dis 2005; 45:588-95. [PMID: 15754282 DOI: 10.1053/j.ajkd.2004.12.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND cblC disease is a cause of hemolytic uremic syndrome (HUS), which has been primarily described in neonates and infants with severe renal and neurological lesions. PATIENTS Two sisters aged 6 and 8.5 years presented with a latent hemolytic process characterized by undetectable or low plasma haptoglobin, respectively, associated with renal failure and gross proteinuria. Renal biopsies performed in both patients found typical findings of thrombotic microangiopathy suggesting the diagnosis of HUS. Both patients were free of neurologic signs. RESULTS Biochemical investigations found a cobalamin processing deficiency of the cblC type. Search for additional factors susceptible to worsen endothelial damage revealed homozygosity 677C--> T mutation in the methylenetetrahydrofolate reductase gene as well as heterozygosity for a 3254T--> C mutation in factor H in the patient with the most severe clinical presentation. Long-term subcutaneous administration of hydroxocobalamin in combination with oral betaine and folic acid resulted in clinical and biological improvement in both patients. CONCLUSION cblC disease may be a cause of chronic HUS with delayed onset in childhood. Superimposed mutation of factor H gene might influence clinical severity.
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Affiliation(s)
- Vincent Guigonis
- Department of Pediatric Nephrology, Hôpital Armand-Trousseau, Paris, France
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13
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Abstract
PURPOSE OF REVIEW Haemolytic uraemic syndrome (HUS) is a disease of diverse origin. The last year has witnessed the identification of a novel genetic marker of this disease, the description of the frequency of the factor H associated form of HUS in a registry of over 100 patients and a better understanding of the pathophysiology of the disease. RECENT FINDINGS In patients with atypical HUS, heterozygous mutations in the gene coding for the soluble complement regulator factor H are reported and most of the mutations cluster in the C-terminal recognition domain of the protein. A novel genetic marker for HUS has also been identified. Mutations occurring in the gene of the von Willebrand factor cleaving protease, ADAMTS13, which were previously linked to thrombotic thrombocytopenic purpura have now been identified in HUS patients. The frequency of factor H-associated HUS was established as 14% in a registry of German speaking countries and also 16 novel disease associated mutations were reported. The pathophysiology of factor H-associated HUS was analysed. Three analysed mutant proteins show normal complement regulatory activities but display defective recognition functions: reduced binding to surface attached C3b, to heparin/polyanions and to endothelial cells. SUMMARY The identification of effector molecules of the complement as well as the coagulation cascade as disease associated molecules indicate a regulatory protein network, which maintains integrity of endothelial cells during stress or infection. Defining the individual components and how their functional interaction causes microangiopathies will identify additional disease markers and will allow the design of proper diagnostic and therapeutic approaches.
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Affiliation(s)
- Peter F Zipfel
- Department of Infection Biology, Hans Knoell Institute for Natural Products Research, Jena, Germany.
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