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Moroniti JJ, Vrbensky JR, Nazy I, Arnold DM. Targeted ADAMTS-13 replacement therapy for thrombotic thrombocytopenic purpura. J Thromb Haemost 2024; 22:896-904. [PMID: 38142844 DOI: 10.1016/j.jtha.2023.11.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 10/27/2023] [Accepted: 11/21/2023] [Indexed: 12/26/2023]
Abstract
Thrombotic thrombocytopenic purpura (TTP) is a life-threatening thrombotic disorder associated with a severe deficiency of ADAMTS-13-the protease that cleaves von Willebrand factor. Plasma therapy is the current standard of care for managing acute episodes of TTP, which involves removing patient plasma and replacing it with donor plasma to raise the level of ADAMTS-13 activity. Recently, therapies aimed at replacing ADAMTS-13 have been investigated as possible substitutes or add-ons to plasma therapy for congenital and immune-mediated TTP. Enzyme replacement therapy provides recombinant ADAMTS-13 via intravenous (i.v.) infusion to restore enzyme activity. Recombinant ADAMTS-13-loaded platelets localize to the site of thrombus formation in a more concentrated manner than enzyme replacement or plasma therapy. ADAMTS-13-encoding messenger RNA aims to induce a steady supply of secreted protein and gene therapy is a potentially curative strategy. Overall, targeted ADAMTS-13 replacement therapies may provide better outcomes than plasma therapy by achieving higher levels of ADAMTS-13 activity and a more sustained response with fewer adverse events. Herein, we describe targeted ADAMTS-13 replacement therapies for the treatment of TTP and discuss the advantages and limitations of each approach.
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Affiliation(s)
- Jonathan J Moroniti
- Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada; Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - John R Vrbensky
- Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Ishac Nazy
- Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada; Michael G. DeGroote Centre for Transfusion Research, McMaster University, Hamilton, Ontario, Canada
| | - Donald M Arnold
- Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada; Michael G. DeGroote Centre for Transfusion Research, McMaster University, Hamilton, Ontario, Canada.
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Irsara C, Anliker M, Egger AE, Harasser L, Lhotta K, Feistritzer C, Griesmacher A, Loacker L. Evaluation of two fully automated ADAMTS13 activity assays in comparison to manual FRET assay. Int J Lab Hematol 2023; 45:758-765. [PMID: 37194625 DOI: 10.1111/ijlh.14090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 05/03/2023] [Indexed: 05/18/2023]
Abstract
INTRODUCTION The objective of the present study was to evaluate and compare the validity and utility of two fully automated ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) activity assays for clinical diagnostic decision-making and to compare their performance. METHODS Two automated ADAMTS13 activity assays (Werfen HemosIL® AcuStar ADAMTS13 Activity, Technoclone Technofluor ADAMTS13 Activity) were compared with a manual FRET assay (BioMedica ACTIFLUOR ADAMTS13 Activity). The following samples were used: 13 acute phase TTP (thrombotic thrombocytopenic purpura) samples from 11 different patients, one sample from a patient with congenital ADAMTS13 deficiency, 16 samples from control patients, three follow-up samples from TTP patients in long-term remission and one sample from a patient with stem cell transplantation related thrombotic microangiopathy (TMA). The WHO 1st International Standard for ADAMTS13 and several dilutions of normal plasma with ADAMTS13-depleted normal plasma were also tested. Statistical analysis included descriptive statistics, sensitivity and specificity, Passing & Bablok regression and Bland-Altman plot. RESULTS The quantitative comparison between the HemosIL® (x) and Technofluor (y) methods showed a strong correlation (Pearson r = 0.98, n = 49). When considering an ADAMTS13 activity of <10% as a hallmark for the diagnosis of TTP, two fully automated assays were both able to identify all TTP- and non-TTP-samples correctly, resulting in sensitivities and specificities of 100%. CONCLUSION Both fully automated ADAMTS13 activity assays showed a good diagnostic performance and quantitative correlation among themselves, discriminating reliably between TTP- and non-TTP-patients.
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Affiliation(s)
- Christian Irsara
- Central Institute of Clinical and Chemical Laboratory Diagnostics, University Hospital of Innsbruck, Innsbruck, Austria
| | - Markus Anliker
- Central Institute of Clinical and Chemical Laboratory Diagnostics, University Hospital of Innsbruck, Innsbruck, Austria
| | - Alexander E Egger
- Central Institute of Clinical and Chemical Laboratory Diagnostics, University Hospital of Innsbruck, Innsbruck, Austria
| | - Lukas Harasser
- Department of Internal Medicine IV, Nephrology and Hypertension, Innsbruck Medical University, Innsbruck, Austria
| | - Karl Lhotta
- Department of Internal Medicine III, Nephrology and Dialysis, Academic Teaching Hospital Feldkirch, Feldkirch, Austria
| | - Clemens Feistritzer
- Department of Internal Medicine V, Hematology and Oncology, Medical University of Innsbruck, Innsbruck, Austria
| | - Andrea Griesmacher
- Central Institute of Clinical and Chemical Laboratory Diagnostics, University Hospital of Innsbruck, Innsbruck, Austria
| | - Lorin Loacker
- Central Institute of Clinical and Chemical Laboratory Diagnostics, University Hospital of Innsbruck, Innsbruck, Austria
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Underwood MI, Alwan F, Thomas MR, Scully MA, Crawley JTB. Autoantibodies enhance ADAMTS-13 clearance in patients with immune thrombotic thrombocytopenic purpura. J Thromb Haemost 2023; 21:1544-1552. [PMID: 36813118 DOI: 10.1016/j.jtha.2023.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/20/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023]
Abstract
BACKGROUND Severe deficiency in ADAMTS-13 (<10%) and the loss of von Willebrand factor-cleaving function can precipitate microvascular thrombosis associated with thrombotic thrombocytopenic purpura (TTP). Patients with immune-mediated TTP (iTTP) have anti-ADAMTS-13 immunoglobulin G antibodies that inhibit ADAMTS-13 function and/or increase ADAMTS-13 clearance. Patients with iTTP are treated primarily by plasma exchange (PEX), often in combination with adjunct therapies that target either the von Willebrand factor-dependent microvascular thrombotic processes (caplacizumab) or the autoimmune components (steroids or rituximab) of the disease. OBJECTIVES To investigate the contributions of autoantibody-mediated ADAMTS-13 clearance and inhibition in patients with iTTP at presentation and through the course of the PEX therapy. PATIENTS/METHODS Anti-ADAMTS-13 immunoglobulin G antibodies, ADAMTS-13 antigen, and activity were measured before and after each PEX in 17 patients with iTTP and 20 acute TTP episodes. RESULTS At presentation, 14 out of 15 patients with iTTP had ADAMTS-13 antigen levels of <10%, suggesting a major contribution of ADAMTS-13 clearance to the deficiency state. After the first PEX, both ADAMTS-13 antigen and activity levels increased similarly, and the anti-ADAMTS-13 autoantibody titer decreased in all patients, revealing ADAMTS-13 inhibition to be a modest modifier of the ADAMTS-13 function in iTTP. Analysis of ADAMTS-13 antigen levels between consecutive PEX treatments revealed that the rate of ADAMTS-13 clearance in 9 out of 14 patients analyzed was 4- to 10-fold faster than the estimated normal rate of clearance. CONCLUSION These data reveal, both at presentation and during PEX treatment, that antibody-mediated clearance of ADAMTS-13 is the major pathogenic mechanism that causes ADAMTS-13 deficiency in iTTP. Understanding the kinetics of ADAMTS-13 clearance in iTTP may now enable further optimization of treatment of patients with iTTP.
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Affiliation(s)
- Mary I Underwood
- Centre for Haematology, Imperial College London, London, United Kingdom
| | - Ferras Alwan
- Haemophilia Centre, Imperial College Healthcare Trust, London, United Kingdom; University College Hospital, London, United Kingdom
| | | | | | - James T B Crawley
- Centre for Haematology, Imperial College London, London, United Kingdom.
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Ballermann BJ, Nyström J, Haraldsson B. The Glomerular Endothelium Restricts Albumin Filtration. Front Med (Lausanne) 2021; 8:766689. [PMID: 34912827 PMCID: PMC8667033 DOI: 10.3389/fmed.2021.766689] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Accepted: 11/05/2021] [Indexed: 12/29/2022] Open
Abstract
Inflammatory activation and/or dysfunction of the glomerular endothelium triggers proteinuria in many systemic and localized vascular disorders. Among them are the thrombotic microangiopathies, many forms of glomerulonephritis, and acute inflammatory episodes like sepsis and COVID-19 illness. Another example is the chronic endothelial dysfunction that develops in cardiovascular disease and in metabolic disorders like diabetes. While the glomerular endothelium is a porous sieve that filters prodigious amounts of water and small solutes, it also bars the bulk of albumin and large plasma proteins from passing into the glomerular filtrate. This endothelial barrier function is ascribed predominantly to the endothelial glycocalyx with its endothelial surface layer, that together form a relatively thick, mucinous coat composed of glycosaminoglycans, proteoglycans, glycolipids, sialomucins and other glycoproteins, as well as secreted and circulating proteins. The glycocalyx/endothelial surface layer not only covers the glomerular endothelium; it extends into the endothelial fenestrae. Some glycocalyx components span or are attached to the apical endothelial cell plasma membrane and form the formal glycocalyx. Other components, including small proteoglycans and circulating proteins like albumin and orosomucoid, form the endothelial surface layer and are bound to the glycocalyx due to weak intermolecular interactions. Indeed, bound plasma albumin is a major constituent of the endothelial surface layer and contributes to its barrier function. A role for glomerular endothelial cells in the barrier of the glomerular capillary wall to protein filtration has been demonstrated by many elegant studies. However, it can only be fully understood in the context of other components, including the glomerular basement membrane, the podocytes and reabsorption of proteins by tubule epithelial cells. Discovery of the precise mechanisms that lead to glycocalyx/endothelial surface layer disruption within glomerular capillaries will hopefully lead to pharmacological interventions that specifically target this important structure.
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Affiliation(s)
| | - Jenny Nyström
- Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Börje Haraldsson
- Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
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Stubbs MJ, Coppo P, Cheshire C, Veyradier A, Dufek S, Levine AP, Thomas M, Patel V, Connolly JO, Hubank M, Benhamou Y, Galicier L, Poullin P, Kleta R, Gale DP, Stanescu H, Scully MA. Identification of a novel genetic locus associated with immune mediated thrombotic thrombocytopenic purpura. Haematologica 2021; 107:574-582. [PMID: 33596643 PMCID: PMC8883548 DOI: 10.3324/haematol.2020.274639] [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: 10/21/2020] [Indexed: 12/05/2022] Open
Abstract
Immune thrombotic thrombocytopenic purpura (iTTP) is an ultra-rare, life-threatening disorder, mediated through severe ADAMTS13 deficiency causing multi-system micro-thrombi formation, and has specific human leukocyte antigen associations. We undertook a large genome-wide association study to investigate additional genetically distinct associations in iTTP. We compared two iTTP patient cohorts with controls, following standardized genome-wide quality control procedures for single-nucleotide polymorphisms and imputed HLA types. Associations were functionally investigated using expression quantitative trait loci (eQTL), and motif binding prediction software. Independent associations consistent with previous findings in iTTP were detected at the HLA locus and in addition a novel association was detected on chromosome 3 (rs9884090, P=5.22x10-10, odds ratio 0.40) in the UK discovery cohort. Meta-analysis, including the French replication cohort, strengthened the associations. The haploblock containing rs9884090 is associated with reduced protein O-glycosyltransferase 1 (POGLUT1) expression (eQTL P<0.05), and functional annotation suggested a potential causative variant (rs71767581). This work implicates POGLUT1 in iTTP pathophysiology and suggests altered post-translational modification of its targets may influence disease susceptibility.
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Affiliation(s)
- Matthew J Stubbs
- Haemostasis Research Unit, UCL (London, UK); Department of Renal Medicine.
| | - Paul Coppo
- Centre de Référence des Microangiopathies Thrombotiques, Hôpital Saint-Antoine (Paris, France)
| | | | - Agnès Veyradier
- Department d'Hematologie, Centre de Référence des Microangiopathies Thrombotiques, Hôpital Lariboisière (Paris, France)
| | | | | | - Mari Thomas
- Haemostasis Research Unit, UCL (London, UK); National Institute for Health Research Cardiometabolic Programme, UCLH/UCL Cardiovascular BRC (London, UK)
| | | | | | | | - Ygal Benhamou
- Centre de Référence des Microangiopathies Thrombotiques, Hôpital Saint-Antoine (Paris, France)
| | - Lionel Galicier
- Centre de Référence des Microangiopathies Thrombotiques, Hôpital Saint-Antoine (Paris, France)
| | - Pascale Poullin
- Centre de Référence des Microangiopathies Thrombotiques, Hôpital Saint-Antoine (Paris, France)
| | | | | | | | - Marie A Scully
- Haemostasis Research Unit, UCL (London, UK); National Institute for Health Research Cardiometabolic Programme, UCLH/UCL Cardiovascular BRC (London, UK)
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Tsai HM. Thrombotic Thrombocytopenic Purpura and Hemolytic-Uremic Syndromes. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00042-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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The role of von Willebrand factor in thrombotic microangiopathy. Pediatr Nephrol 2018; 33:1297-1307. [PMID: 28748411 DOI: 10.1007/s00467-017-3744-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 06/05/2017] [Accepted: 06/21/2017] [Indexed: 01/09/2023]
Abstract
Thrombotic microangiopathy (TMA) is caused by thrombus formation in the microvasculature. The disease spectrum of TMA includes, amongst others, thrombotic thrombocytopenic purpura (TTP) and atypical haemolytic uraemic syndrome (aHUS). TTP is caused by defective cleavage of von Willebrand factor (VWF), whereas aHUS is caused by overshooting complement activation and subsequent endothelial cell (EC) injury. Despite their distinct pathophysiology, the clinical manifestation of TTP and aHUS consisting of microangiopathic haemolytic anaemia and thrombocytopenia is often similar and difficult to distinguish. Recent evidence hints at both a genetic and functional link between TTP and aHUS, especially between VWF and the complement system. There is novel in vitro evidence that complement activation not only results in VWF release from ECs, but that VWF also functions as a negative complement regulator, thus protecting the EC surface from ongoing complement attack. Although contrary to previous experimental work suggesting that complement can be activated on VWF multimers, there may be an explanation in vivo that rationalizes these apparently contradictory findings, whereby a system primarily meant to regulate becomes overwhelmed or pathologic in the disease state. The importance of unravelling these recent findings for our understanding of TMA pathology becomes even more evident considering that glomerular ECs express VWF in a heterogeneous pattern with an overall decreased expression level, thus potentially leaving the glomerular ECs vulnerable to complement-mediated injury. Taken together, these findings support the concept that TTP and aHUS represent two extreme ends of a TMA disease spectrum rather than isolated disease entities.
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Alwan F, Vendramin C, Vanhoorelbeke K, Langley K, McDonald V, Austin S, Clark A, Lester W, Gooding R, Biss T, Dutt T, Cooper N, Chapman O, Cranfield T, Douglas K, Watson HG, van Veen JJ, Sibson K, Thomas W, Manson L, Hill QA, Benjamin S, Ellis D, Westwood JP, Thomas M, Scully M. Presenting ADAMTS13 antibody and antigen levels predict prognosis in immune-mediated thrombotic thrombocytopenic purpura. Blood 2017; 130:466-471. [PMID: 28576877 DOI: 10.1182/blood-2016-12-758656] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 05/02/2017] [Indexed: 02/04/2023] Open
Abstract
Immune-mediated thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder caused by antibodies against ADAMTS13. From the United Kingdom TTP registry, we undertook a prospective study investigating the impact of the presenting anti-ADAMTS13 IgG antibody and ADAMTS13 antigen on mortality. A total of 312 episodes involving 292 patients over 87 months were included; 68% were female, median age 46 (range, 11-88 years), and median presenting ADAMTS13 of <5% (range, <5%-18%). The mortality rate was 10.3% (n = 32); 68% of patients had a raised troponin at presentation conferring a sixfold increase in mortality compared with those with normal troponin levels (12.1% vs 2.0%, P = .04). Twenty-four percent had a reduced Glasgow Coma Score (GCS) at presentation with a ninefold increase in mortality (20% vs 2.2% for normal GCS at presentation, P < .0001). Mortality increased with higher anti-ADAMTS13 antibody levels and lower ADAMTS13 antigen levels. Those with antibody levels in the upper quartile (antibody >77%) had a mortality of 16.9% compared with 5.0% for the lowest quartile (antibody <20%) (P = .004). Those with an antigen level in the lowest quartile (antigen <1.5%) had a mortality of 18% compared with 3.8% for the highest quartile (antigen >11%) (P = .005). The synergistic effect of anti-ADAMTS13 IgG antibody in the upper quartile and ADAMTS13 antigen in the lowest quartile had the highest mortality of 27.3%. We conclude that both anti-ADAMTS13 IgG antibody and ADAMTS13 antigen levels correlate with outcome in TTP with increased cardiac and neurological involvement and increased mortality.
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Affiliation(s)
| | - Chiara Vendramin
- Haemostasis Research Unit, University College London, London, United Kingdom
| | - Karen Vanhoorelbeke
- Laboratory for Thrombosis Research, Katholieke Universiteit Leuven Campus Kulak Kortrijk, Kortrijk, Belgium
| | - Katy Langley
- Haemostasis Research Unit, University College London, London, United Kingdom
| | - Vickie McDonald
- Department of Haematology, Guys and St Thomas National Health Service (NHS) Trust, London, United Kingdom
| | - Steve Austin
- Department of Haematology, St George's NHS Trust, London, United Kingdom
| | - Amanda Clark
- Bristol Haemophilia Centre, University Hospitals Bristol Foundation Trust, Bristol, United Kingdom
| | - William Lester
- Department of Haematology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Richard Gooding
- Department of Haematology, University Hospitals of Leicester, Leicester, United Kingdom
| | - Tina Biss
- Department of Haematology, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle, United Kingdom
| | - Tina Dutt
- Roald Dahl Haemostasis and Thrombosis Centre, Royal Liverpool University Hospital, Liverpool, United Kingdom
| | - Nichola Cooper
- Department of Haematology, Imperial College NHS Trust, London, United Kingdom
| | - Oliver Chapman
- Department of Haematology, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, United Kingdom
| | - Tanya Cranfield
- Department of Haematology, Queen Alexandra Hospital, Portsmouth, United Kingdom
| | - Kenny Douglas
- Scottish National Blood Transfusion Service (SNBTS) Clinical Apheresis Unit, Beatson West of Scotland Cancer Centre, Glasgow, United Kingdom
| | - H G Watson
- Department of Haematology, Aberdeen Royal Infirmary, Aberdeen, United Kingdom
| | - J J van Veen
- Department of Haematology, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom
| | - Keith Sibson
- Department of Haematology, Great Ormond Street Hospital, London, United Kingdom
| | - William Thomas
- Department of Haematology, Addenbrookes Hospital, Cambridge, United Kingdom
| | - Lynn Manson
- SNBTS Department of Transfusion Medicine, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
| | - Quentin A Hill
- Department of Haematology, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
| | - Sylvia Benjamin
- Department of Clinical Haematology, Oxford University Hospitals, Oxford, United Kingdom; and
| | | | | | - Mari Thomas
- Department of Haematology and
- National Institute for Health Research Cardiometabolic Programme, University College London (UCL) Hospitals/UCL Biomedical Research Centre, London, United Kingdom
| | - Marie Scully
- Department of Haematology and
- National Institute for Health Research Cardiometabolic Programme, University College London (UCL) Hospitals/UCL Biomedical Research Centre, London, United Kingdom
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Joly BS, Stepanian A, Leblanc T, Hajage D, Chambost H, Harambat J, Fouyssac F, Guigonis V, Leverger G, Ulinski T, Kwon T, Loirat C, Coppo P, Veyradier A. Child-onset and adolescent-onset acquired thrombotic thrombocytopenic purpura with severe ADAMTS13 deficiency: a cohort study of the French national registry for thrombotic microangiopathy. LANCET HAEMATOLOGY 2016; 3:e537-e546. [PMID: 27720178 DOI: 10.1016/s2352-3026(16)30125-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 08/10/2016] [Accepted: 08/11/2016] [Indexed: 12/14/2022]
Abstract
BACKGROUND Thrombotic thrombocytopenic purpura is a rare thrombotic microangiopathy, related to a severe ADAMTS13 deficiency (a disintegrin and metalloprotease with thromboSpondin type 1 repeats, member 13; activity <10% of normal). Childhood-onset thrombotic thrombocytopenic purpura is very rare and initially often misdiagnosed, especially when ADAMTS13 deficiency is acquired (ie, not linked to inherited mutations of the ADAMTS13 gene). We aimed to investigate initial presentation, management, and outcome of acquired thrombotic thrombocytopenic purpura in children. METHODS Between Jan 1, 2000, and Dec 31, 2015, we studied a cohort of patients with child-onset and adolescent-onset acquired thrombotic thrombocytopenic purpura included in the French national registry for thrombotic microangiopathies at presentation and during follow up. The inclusion criteria were: first episode before age 18 years; ADAMTS13 activity less than 10% of normal at presentation; positive anti-ADAMTS13 autoantibodies during an episode, or a recovery of ADAMTS13 activity in remission, or both. ADAMTS13 activity and anti-ADAMTS13 autoantibodies were investigated by a central laboratory, and medical records were extensively reviewed to collect clinical and biological features with a standardised form. This study is registered with ClinicalTrials.gov, number NCT00426686. FINDINGS We enrolled 973 patients with childhood-onset thrombotic microangiopathy, of whom 74 had a severe ADAMTS13 deficiency (activity <10%) at presentation. 24 patients had an inherited thrombotic thrombocytopenic purpura also known as Upshaw-Schulman syndrome and five did not have follow-up data available, thus 45 children had acquired thrombotic thrombocytopenic purpura and were included in our database at presentation. 25 (56%) patients had idiopathic disease and 20 (44%) had miscellaneous associated clinical conditions. At diagnosis, median age was 13 years (IQR 7-16, range 4 months-17 years), with a sex ratio of 2·5 girls to 1 boy. Anti-ADAMTS13 autoantibodies were positive in 37 (82%) of 45 patients (24 [96%] of 25 idiopathic cases and 13 [65%] of 20 non-idiopathic cases). 39 (87%) of 45 patients were given plasma therapy and 21 (47%) received additional rituximab. Four (9%) children died after the first thrombotic thrombocytopenic purpura episode. Long-term follow up of the 41 survivors showed that ten (24%) patients relapsed and systemic lupus erythematosus occurred in two (5%) patients. Preemptive rituximab was used in seven (17%) of 41 patients with acquired thrombotic thrombocytopenic purpura. INTERPRETATION Our study shows that child-onset and adolescent-onset acquired thrombotic thrombocytopenic purpura have specific clinical, biological and therapeutic features. Long-term follow-up is crucial to prevent relapses of the disease, to identify the occurrence of autoimmune disorders, and to evaluate consequences on social life. Child-onset and adolescent-onset acquired thrombotic thrombocytopenic purpura is a crucial diagnosis in the field of paediatric haematologic cytopenias because it is a life-threatening disease requiring a specific management. FUNDING Assistance Publique-Hôpitaux de Paris, France.
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Affiliation(s)
- Bérangère S Joly
- Service d'Hématologie biologique, Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris and EA3518, Institut Universitaire d'Hématologie-Hôpital Saint Louis, Université Paris Diderot, Paris, France
| | - Alain Stepanian
- Service d'Hématologie biologique, Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris and EA3518, Institut Universitaire d'Hématologie-Hôpital Saint Louis, Université Paris Diderot, Paris, France
| | - Thierry Leblanc
- Service d'Hématologie clinique, Hôpital Robert Debré, Assistance Publique-Hôpitaux de Paris, Université Paris Diderot, Paris, France
| | - David Hajage
- Département d'Epidémiologie et recherche clinique, Hôpital Louis Mourier, Assistance Publique-Hôpitaux de Paris, Université Paris Diderot, Paris, France
| | - Hervé Chambost
- Service d'Hématologie clinique pédiatrique, Hôpital La Timone, Assistance Publique-Hôpitaux de Marseille, Marseille, France
| | - Jérôme Harambat
- Service de Pédiatrie, Hôpital Pellegrin, CHU de Bordeaux, Bordeaux, France
| | - Fanny Fouyssac
- Département d'Oncologie et d'Hématologie Pédiatriques et de Thérapie Cellulaire, CHU de Nancy, Hôpital d'Enfants, Vandoeuvre-lès-Nancy, France
| | | | - Guy Leverger
- Service d'Oncologie pédiatrique, Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Université Pierre et Marie Curie, Paris, France
| | - Tim Ulinski
- Service de Néphrologie pédiatrique, Hôpital Trousseau, Assistance Publique-Hôpitaux de Paris, Université Pierre et Marie Curie, Paris, France
| | - Thérésa Kwon
- Service de Néphrologie pédiatrique, Hôpital Robert Debré, Assistance Publique-Hôpitaux de Paris, Université Paris Diderot, Paris, France
| | - Chantal Loirat
- Service de Néphrologie pédiatrique, Hôpital Robert Debré, Assistance Publique-Hôpitaux de Paris, Université Paris Diderot, Paris, France
| | - Paul Coppo
- Département d'Hématologie clinique, Hôpital Saint Antoine, Assistance Publique-Hôpitaux de Paris, Université Pierre et Marie Curie, Paris, France
| | - Agnès Veyradier
- Service d'Hématologie biologique, Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris and EA3518, Institut Universitaire d'Hématologie-Hôpital Saint Louis, Université Paris Diderot, Paris, France.
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Mai Falk J, Scharrer I. Idiopathic thrombotic thrombocytopenic purpura: strongest risk factor for relapse from remission is having had a relapse. Transfusion 2016; 56:2819-2823. [PMID: 27514869 DOI: 10.1111/trf.13751] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 05/17/2016] [Accepted: 06/20/2016] [Indexed: 01/05/2023]
Abstract
BACKGROUND Thrombotic thrombocytopenic purpura (TTP) is a rare, episodic clinical syndrome involving the production of thrombi in the microvasculature accompanied by thrombocytopenia and symptoms of organ ischemia. Idiopathic TTP develops when a patient produces antibodies that react with the protease ADAMTS13. The course after an episode is unpredictable; patients may relapse frequently or never. There is no laboratory value that can reliably predict potential relapse. STUDY DESIGN AND METHODS To assess diagnostic and predictive values for risk of relapse, plasma samples from 27 patients with idiopathic TTP in remission were analyzed for anti-ADAMTS13 immunoglobulin (Ig)G, ADAMTS13 activity, and ADAMTS13 inhibitor titer. Patients were recruited at the Department of Hematology at the University Medical Center, Johannes Gutenberg University Mainz, Mainz, Germany. RESULTS Anti-ADAMTS13 IgG was detected in 12 patients (44%); their median level of ADAMTS13 activity was nondetectable. Patients with anti-ADAMTS13 IgG had a median number of three previous relapses, whereas the 15 patients without presence of IgG (56%) had a median number of one previous relapse (p < 0.001; Mann-Whitney U test). The concentration of free anti-ADAMTS13 IgG and the levels measuring inhibitory activity (Bethesda unit) were positively correlated. CONCLUSION A subgroup of TTP patients in remission with anti-ADAMTS13 IgG and nondetectable ADAMTS13 activity showed an increased risk for relapsing disease as demonstrated by their number of past relapses. The positive correlation we observed between anti-ADAMTS13 IgG and inhibitor levels supports the theory of ADAMTS13 inhibition as the crucial mechanism causing severe deficiency in ADAMTS13 activity in TTP.
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Affiliation(s)
- Jennifer Mai Falk
- Department of Hematology at the University Medical Center, Johannes Gutenberg University Mainz, Mainz, Germany
| | - Inge Scharrer
- Department of Hematology at the University Medical Center, Johannes Gutenberg University Mainz, Mainz, Germany
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11
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Zheng XL. Structure-function and regulation of ADAMTS-13 protease. J Thromb Haemost 2013; 11 Suppl 1:11-23. [PMID: 23809107 PMCID: PMC3713533 DOI: 10.1111/jth.12221] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 03/03/2013] [Indexed: 12/11/2022]
Abstract
ADAMTS-13, a plasma reprolysin-like metalloprotease, cleaves von Willebrand factor (VWF). Severe deficiency of plasma ADAMTS-13 activity results in thrombotic thrombocytopenic purpura (TTP), while mild to moderate deficiencies of plasma ADAMTS-13 activity are emerging risk factors for developing myocardial and cerebral infarction, pre-eclampsia, and malignant malaria. Moreover, Adamts13(-/-) mice develop more severe inflammatory responses, leading to increased ischemia/perfusion injury and formation of atherosclerosis. Structure-function studies demonstrate that the N-terminal portion of ADAMTS-13 (MDTCS) is necessary and sufficient for proteolytic cleavage of VWF under various conditions and attenuation of arterial/venous thrombosis after oxidative injury. The more distal portion of ADAMTS-13 (TSP1 2-8 repeats and CUB domains) may function as a disulfide bond reductase to prevent an elongation of ultra-large VWF strings on activated endothelial cells and inhibit platelet adhesion/aggregation on collagen surface under flow. Remarkably, the proteolytic cleavage of VWF by ADAMTS-13 is accelerated by FVIII and platelets under fluid shear stress. A disruption of the interactions between FVIII (or platelet glycoprotein 1bα) and VWF dramatically impairs ADAMTS-13-dependent proteolysis of VWF in vitro and in vivo. These results suggest that FVIII and platelets may be physiological cofactors regulating VWF proteolysis. Finally, the structure-function and autoantibody mapping studies allow us to identify an ADAMTS-13 variant with increased specific activity but reduced inhibition by autoantibodies in patients with acquired TTP. Together, these findings provide novel insight into the mechanism of VWF proteolysis and tools for the therapy of acquired TTP and perhaps other arterial thrombotic disorders.
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Affiliation(s)
- X L Zheng
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA.
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12
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Mancini I, Valsecchi C, Palla R, Lotta LA, Peyvandi F. Measurement of anti-ADAMTS13 neutralizing autoantibodies: a comparison between CBA and FRET assays. J Thromb Haemost 2012; 10:1439-42. [PMID: 22507459 DOI: 10.1111/j.1538-7836.2012.04744.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Gain-of-function ADAMTS13 variants that are resistant to autoantibodies against ADAMTS13 in patients with acquired thrombotic thrombocytopenic purpura. Blood 2012; 119:3836-43. [PMID: 22289888 DOI: 10.1182/blood-2011-12-399501] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Thrombotic thrombocytopenic purpura (TTP) is primarily caused by immunoglobulin G (IgG) autoantibodies against A Disintegrin And Metalloprotease with ThromboSpondin type 1 repeats, 13 (ADAMTS13). Nearly all adult idiopathic TTP patients harbor IgGs, which bind the spacer domain of ADAMTS13, a region critical for recognition and proteolysis of von Willebrand factor (VWF). We hypothesize that a modification of an exosite in the spacer domain may generate ADAMTS13 variants with reduced autoantibody binding while preserving or enhancing specific activity. Site-directed mutagenesis was used to generate a series of ADAMTS13 variants, and their functional properties were assessed. Of 24 novel ADAMTS13 variants, 2 (ie, M4, R660K/F592Y/R568K/Y661F and M5, R660K/F592Y/R568K/Y661F/Y665F) exhibited increased specific activity approximately 4- to 5-fold and approximately 10- to 12-fold cleaving a peptide VWF73 substrate and multimeric VWF, respectively. More interestingly, the gain-of-function ADAMTS13 variants were more resistant to inhibition by anti-ADAMTS13 autoantibodies from patients with acquired idiopathic TTP because of reduced binding by anti-ADAMTS13 IgGs. These results shed more light on the critical role of the exosite in the spacer domain in substrate recognition. Our findings also help understand the pathogenesis of acquired autoimmune TTP. The autoantibody-resistant ADAMTS13 variants may be further developed as a novel therapeutic for acquired TTP with inhibitors.
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14
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Li D, Xiao J, Paessler M, Zheng XL. Novel recombinant glycosylphosphatidylinositol (GPI)-anchored ADAMTS13 and variants for assessment of anti-ADAMTS13 autoantibodies in patients with thrombotic thrombocytopenic purpura. Thromb Haemost 2011; 106:947-58. [PMID: 21901237 DOI: 10.1160/th11-05-0337] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 07/19/2011] [Indexed: 11/05/2022]
Abstract
Immunoglobulin Gs (IgGs) against ADAMTS13 are major causes of acquired (idiopathic) thrombotic thrombocytopenic purpura (TTP). We report here a novel cell-based assay using glycosylphosphatidylinositol (GPI)-anchored ADAMTS13 or variants expressed on cell membrane for assessment of autoantibodies in patients with TTP. We showed that IgGs from all 26 patients with acquired TTP bound to cells expressing a GPI anchored full-length ADAMTS13 (gFL) and a variant truncated after the spacer domain (gS). Also, IgGs from 25/26 (96.7%) of these TTP patients bound to cells expressing a GPI-anchored C-terminal fragment, TSP1 2-8 plus CUB (gT2C). In contrast, none of the 20 healthy blood donors showed detectable binding of their IgGs to the cells expressing gFL, gS, and gT2C. A moderate, but statistically significant correlation was observed between plasma concentrations of anti-ADAMTS13 IgG and positive cells expressing gFL (r=0.65), gS (r=0.67), and gT2C (r=0.42). These results suggest that the microtiter-plate assay and the cell-based assay may detect differential antigenic epitopes. Moreover, antigens clustered on cell membranes may enhance antibody binding affinity, thereby increasing analytical sensitivity. Finally, our assay was able to determine kinetic changes of plasma levels of anti-ADAMTS13 IgGs in TTP patients during plasma therapy. Together, our findings suggest that the novel cell-based assay may be applicable for rapid identification and mapping of anti-ADAMTS13 autoantibodies in patients with acquired TTP.
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Affiliation(s)
- D Li
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
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15
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Plaimauer B, Kremer Hovinga JA, Juno C, Wolfsegger MJ, Skalicky S, Schmidt M, Grillberger L, Hasslacher M, Knöbl P, Ehrlich H, Scheiflinger F. Recombinant ADAMTS13 normalizes von Willebrand factor-cleaving activity in plasma of acquired TTP patients by overriding inhibitory antibodies. J Thromb Haemost 2011; 9:936-44. [PMID: 21294825 DOI: 10.1111/j.1538-7836.2011.04224.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Severe deficiency of the von Willebrand factor (VWF)-cleaving protease ADAMTS13 as observed in acquired thrombotic thrombocytopenic purpura (TTP) is caused by inhibitory and non-inhibitory autoantibodies directed against the protease. Current treatment with plasma exchange is considered to remove circulating antibodies and to concurrently replenish the deficient enzyme. OBJECTIVES To explore the use of recombinant ADAMTS13 (rADAMTS13) as a potential therapeutic agent in acquired TTP, we investigated its efficacy in normalizing VWF-cleaving activity in the presence of ADAMTS13 inhibitors. METHODS Thirty-six plasma samples from TTP patients were adjusted to predefined inhibitor titers, and recovery of ADAMTS13 activity was analyzed following supplementation with rADAMTS13. RESULTS We showed a linear relation between the inhibitor titer measured and effective rADAMTS13 concentration necessary for reconstitution of VWF-cleaving activity in the presence of neutralizing autoantibodies. CONCLUSIONS Our results support the further investigation of the potential therapeutic applicability of rADAMTS13 as an adjunctive therapy in acquired TTP.
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Affiliation(s)
- B Plaimauer
- Baxter Innovations GmbH, Wagramer Strasse, Vienna, Austria
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16
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Abstract
We aimed to describe the characteristics, treatment regime, and 6-month all-cause mortality of thrombotic thrombocytopenic purpura (TTP) patients treated with total plasma exchange in the our clinic. Thirteen patients were included in the study. Mortality rates of TTP have improved over the last three decades but they are still too high according to modern therapy expectations. Etiology directed treatment should be added to total plasma exchange in secondary TTP cases. Based on TTPs' immunologic etiology, immune modulator and immune suppressor agents have been applied together with total plasma exchange, but mostly in anecdotal case reports or with questionable responses.
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17
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Lombardi AM, Berti de Marinis G, Scandellari R, Magalini F, Sansoni P, Ballerini PF, Vettore S, Candeo N, Marson P, De Silvestro G, Fabris F. Clinical biological remission induced by rituximab in acute refractory chronic relapsing TTP. Thromb Res 2010; 126:e154-6. [DOI: 10.1016/j.thromres.2010.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 02/03/2010] [Accepted: 02/04/2010] [Indexed: 10/19/2022]
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18
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Lambot F, Hanson B, Sztern B. [Thrombotic thrombocytopenic purpura mediated by an ADAMTS13-inhibitor related to a treatment with pegylated-interferon alpha-2a and ribavirine in a patient with chronic hepatitis C]. Presse Med 2010; 39:1207-10. [PMID: 20609558 DOI: 10.1016/j.lpm.2010.04.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2009] [Revised: 04/12/2010] [Accepted: 04/19/2010] [Indexed: 11/29/2022] Open
Affiliation(s)
- Frédéric Lambot
- Hôpital Molière-Longchamps, HIS, médecine interne, Bruxelles, 1190 Bruxelles, Belgique.
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19
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Manea M, Tati R, Karlsson J, Békássy ZD, Karpman D. Biologically active ADAMTS13 is expressed in renal tubular epithelial cells. Pediatr Nephrol 2010; 25:87-96. [PMID: 19644711 DOI: 10.1007/s00467-009-1262-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 06/25/2009] [Accepted: 06/26/2009] [Indexed: 11/24/2022]
Abstract
ADAMTS13 mRNA, which encodes the von Willebrand factor-cleaving protease, has been detected in a variety of tissues, including the kidney. The aim of our study was to characterize tubular expression and bioactivity of ADAMTS13. ADAMTS13 mRNA was detected in cultured primary human renal tubular epithelial cells (HRTEC) and in A498 cells, a human renal carcinoma cell line, by real-time PCR. Protein was detected using immunofluorescence and immunoblotting. Immunoblots demonstrated that the protein was secreted. The protease was proteolytically active in both cell lysates and cleaved the FRETS–VWF73 substrate. ADAMTS13 was demonstrated in situ in the renal cortex by immunohistochemistry. Protease was detected in both the proximal and distal renal tubules in normal renal tissue (n=3) as well as in patients with tubular disorders (n=3). Immunoblotting revealed that ADAMTS13 was present in the urine of patients with tubulopathy (n=5) but not in normal urine. ADAMTS13 in urine had a molecular size similar to that in plasma, which indicates that the protease originates in the tubuli because such large proteins do not normally pass the glomerular filter. In conclusion, human renal tubular epithelial cells synthesize biologically active ADAMTS13 which may, after release from tubuli, regulate hemostasis in the local microenvironment.
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Affiliation(s)
- Minola Manea
- Department of Pediatrics, Clinical Sciences Lund, Lund University, 22185 Lund, Sweden
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20
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Sauna ZE, Okunji C, Hunt RC, Gupta T, Allen CE, Plum E, Blaisdell A, Grigoryan V, S G, Fathke R, Soejima K, Kimchi-Sarfaty C. Characterization of conformation-sensitive antibodies to ADAMTS13, the von Willebrand cleavage protease. PLoS One 2009; 4:e6506. [PMID: 19654870 PMCID: PMC2716513 DOI: 10.1371/journal.pone.0006506] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Accepted: 06/27/2009] [Indexed: 12/17/2022] Open
Abstract
Background The zinc metalloprotease ADAMTS13 is a multidomain protein that cleaves von Willebrand Factor (VWF) and is implicated in Thrombotic Thrombocytopenic Purpura (TTP) pathogenesis. Understanding the mechanism of this protein is an important goal. Conformation sensitive antibodies have been used to monitor protein conformation and to decipher the molecular mechanism of proteins as well as to distinguish functional and non-functional mutants. Methodology/Principal Findings We have characterized several antibodies against ADAMTS13, both monoclonal and polyclonal. We have used flow cytometry to estimate the binding of these antibodies to ADAMTS13 and demonstrate that antibodies raised against the TSP and disintegrin domains detect conformation changes in the ADAMTS13. Thus for example, increased binding of these antibodies was detected in the presence of the substrate (VWF), mainly at 37°C and not at 4°C. These antibodies could also detect differences between wild-type ADAMTS13 and the catalytically deficient mutant (P475S). The flow cytometry approach also allows us to estimate the reactivity of the antibody as well as its apparent affinity. Conclusions/Significance Our results suggest that these antibodies may serve as useful reagents to distinguish functional and non-functional ADAMTS13 and analyze conformational transitions to understand the catalytic mechanism.
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Affiliation(s)
- Zuben E. Sauna
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
- * E-mail: (ZES); (CKS)
| | - Chinyere Okunji
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Ryan C. Hunt
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Tanvi Gupta
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Courtni E. Allen
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Elizabeth Plum
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Adam Blaisdell
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Vahan Grigoryan
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Geetha S
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Robert Fathke
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
| | - Kenji Soejima
- First Research Department, the Chemo-Sero-Therapeutic Research Institute, Kumamoto, Japan
| | - Chava Kimchi-Sarfaty
- Laboratory of Hemostasis, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, United States of America
- * E-mail: (ZES); (CKS)
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21
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Manea M, Karpman D. Molecular basis of ADAMTS13 dysfunction in thrombotic thrombocytopenic purpura. Pediatr Nephrol 2009; 24:447-58. [PMID: 18807073 DOI: 10.1007/s00467-008-0986-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 07/14/2008] [Accepted: 07/18/2008] [Indexed: 10/21/2022]
Abstract
Thrombotic thrombocytopenic purpura (TTP) is a thrombotic microangiopathic disorder characterized by thrombocytopenia, hemolytic anemia, neurological and renal manifestations, and fever. It is associated with dysfunctional von Willebrand factor (VWF) proteolysis and the occurrence of VWF- and platelet-rich thrombi in the microcirculation of multiple organs, including the kidneys. Von Willebrand factor is a large glycoprotein that circulates in plasma as a series of multimers, and it plays a major role in primary hemostasis by inducing the formation of platelet plugs at sites of vascular injury and high-shear stress. Its activity is dependent on the sizes of the multimers, with ultra-large (UL) VWF multimers being biologically very potent. The ULVWF multimers are rapidly degraded upon their secretion from endothelial cells in normal individuals but not in the circulation of TTP patients, causing the formation of disseminated thrombi in the latter. The defective breakdown of VWF is attributed to a severely deficient activity of the VWF-cleaving protease ADAMTS13, a plasma metalloprotease synthesized in the liver, kidneys, and endothelium. This protease rapidly degrades VWF-platelet strings under flow by proteolytic cleavage of the VWF subunit, thereby regulating the size of the platelet thrombus. Congenital TTP occurs due to ADAMTS13 mutations, with the usual debut occurring during the first years of life, while acquired TTP is associated with auto-antibodies against ADAMTS13.
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Affiliation(s)
- Minola Manea
- Department of Pediatrics, Clinical Sciences Lund, Lund University, 22185, Lund, Sweden
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22
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Tsai HM. Thrombotic thrombocytopenic purpura: a thrombotic disorder caused by ADAMTS13 deficiency. Hematol Oncol Clin North Am 2007; 21:609-32, v. [PMID: 17666281 PMCID: PMC2001253 DOI: 10.1016/j.hoc.2007.06.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A serious disorder with characteristic microvascular thrombosis involving the brain and other organs, thrombotic thrombocytopenic purpura (TTP) typically presents with thrombocytopenia, hemolysis with schistocytes on blood smears, and mental changes or seizures. It may progress rapidly to a fatal end if the patient is not treated immediately with plasma. Recent advances have shown that TTP is caused by deficiency of a circulating, von Willebrand factor cleaving metalloprotease, ADAMTS13. This new knowledge will provide clues to improve the diagnosis and management of this intriguing disease.
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Affiliation(s)
- Han-Mou Tsai
- Division of Hematology, Albert Einstein College of Medicine and Montefiore Medical Center, 111 East 210th Street, Bronx, NY 10467, USA.
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23
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Ferrari S, Scheiflinger F, Rieger M, Mudde G, Wolf M, Coppo P, Girma JP, Azoulay E, Brun-Buisson C, Fakhouri F, Mira JP, Oksenhendler E, Poullin P, Rondeau E, Schleinitz N, Schlemmer B, Teboul JL, Vanhille P, Vernant JP, Meyer D, Veyradier A. Prognostic value of anti-ADAMTS 13 antibody features (Ig isotype, titer, and inhibitory effect) in a cohort of 35 adult French patients undergoing a first episode of thrombotic microangiopathy with undetectable ADAMTS 13 activity. Blood 2007; 109:2815-22. [PMID: 17164349 DOI: 10.1182/blood-2006-02-006064] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
To study both the pathophysiologic and the prognostic value of ADAMTS13 in thrombotic microangiopathies (TMAs), we enrolled a cohort of 35 adult patients combining a first acute episode of TMA, an undetectable (below 5%) ADAMTS13 activity in plasma, and no clinical background such as sepsis, cancer, HIV, and transplantation. All patients were treated by steroids and plasma exchange, and an 18-month follow-up was scheduled. Remission was obtained in 32 patients (91.4%), and 3 patients died (8.6%) after the first attack. At presentation, ADAMTS13 antigen was decreased in 32 patients (91.4%), an ADAMTS13 inhibitor was detectable in 31 patients (89%), and an anti-ADAMTS13 IgG/IgM/IgA was present in 33 patients (94%). The 3 decedent patients were characterized by the association of several anti-ADAMTS13 Ig isotypes, including very high IgA titers, while mortality was independent of the ADAMTS13 inhibitor titer. In survivors, ADAMTS13 activity in remission increased to levels above 15% in 19 patients (59%) but remained undetectable in 13 patients (41%). Six patients relapsed either once or twice (19%) during the follow-up. High levels of inhibitory anti-ADAMTS13 IgG at presentation were associated with the persistence of an undetectable ADAMTS13 activity in remission, the latter being predictive for relapses within an 18-month delay.
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Affiliation(s)
- Silvia Ferrari
- Baxter Bioscience, Department of Discovery Research and Technical Assessment, Vienna, Austria
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24
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Abstract
PURPOSE OF REVIEW Thrombotic thrombocytopenic purpura can be induced by acquired or congenital deficiency of the plasma von Willebrand factor-cleaving protease, ADAMTS13. Measurement of ADAMTS13 activity is important for the diagnosis and treatment of microangiopathies including thrombotic thrombocytopenic purpura. Phenotypic analysis of mice lacking the Adamts13 gene is valuable for understanding the pathogenesis of microangiopathies. RECENT FINDINGS The minimum substrate for ADAMTS13 activity was identified as 73 amino acid residues in the A2 domain of von Willebrand factor, called VWF73. Several new assays have been developed using this sequence. The VWF73-based assays are rapid, quantitative, and easy to handle, and are well correlated with the measures from previous assays. Mice lacking the Adamts13 gene were produced. The mice were viable and fertile. They showed a prothrombotic state but no symptoms of spontaneous thrombocytopenia, hemolytic anemia, or microvascular thrombosis were observed. SUMMARY VWF73-based ADAMTS13 assays will significantly facilitate the accurate diagnosis of microangiopathies and contribute to the improved clinical treatment of these diseases. Accumulated clinical information on patients with ADAMTS13 deficiency and mice lacking the Adamts13 gene indicates that additional environmental or genetic susceptibility factors are required to trigger thrombotic thrombocytopenic purpura.
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Affiliation(s)
- Toshiyuki Miyata
- National Cardiovascular Center Research Institute, Fujishirodai, Suita, Osaka, Japan.
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25
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Manea M, Kristoffersson A, Tsai HM, Zhou W, Winqvist I, Oldaeus G, Billström R, Björk P, Holmberg L, Karpman D. ADAMTS13 phenotype in plasma from normal individuals and patients with thrombotic thrombocytopenic purpura. Eur J Pediatr 2007; 166:249-57. [PMID: 17187257 PMCID: PMC1820762 DOI: 10.1007/s00431-006-0354-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Accepted: 10/24/2006] [Indexed: 12/03/2022]
Abstract
The activity of ADAMTS13, the von Willebrand factor cleaving protease, is deficient in patients with thrombotic thrombocytopenic purpura (TTP). In the present study, the phenotype of ADAMTS13 in TTP and in normal plasma was demonstrated by immunoblotting. Normal plasma (n = 20) revealed a single band at 190 kD under reducing conditions using a polyclonal antibody, and a single band at 150 kD under non-reducing conditions using a monoclonal antibody. ADAMTS13 was not detected in the plasma from patients with congenital TTP (n = 5) by either antibody, whereas patients with acquired TTP (n = 2) presented the normal phenotype. Following immunoadsorption of immunoglobulins, the ADAMTS13 band was removed from the plasma of the patients with acquired TTP, but not from that of normal individuals. This indicates that ADAMTS13 is complexed with immunoglobulin in these patients. The lack of ADAMTS13 expression in the plasma from patients with hereditary TTP may indicate defective synthesis, impaired cellular secretion, or enhanced degradation in the circulation. This study differentiated between normal and TTP plasma, as well as between congenital and acquired TTP. This method may, therefore, be used as a complement in the diagnosis of TTP.
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Affiliation(s)
- Minola Manea
- Department of Pediatrics, Clinical Sciences Lund, Lund University, 221 84 Lund, Sweden
| | | | - Han-Mou Tsai
- Division of Hematology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY USA
| | - Wenhua Zhou
- Division of Hematology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY USA
| | - Ingemar Winqvist
- Department of Hematology, Lund University Hospital, Lund, Sweden
| | - Göran Oldaeus
- Department of Pediatrics, Länssjukhuset Ryhov, Jönköping, Sweden
| | | | - Peter Björk
- Department of Medicine, Malmö University Hospital, Malmö, Sweden
| | - Lars Holmberg
- Department of Pediatrics, Clinical Sciences Lund, Lund University, 221 84 Lund, Sweden
| | - Diana Karpman
- Department of Pediatrics, Clinical Sciences Lund, Lund University, 221 84 Lund, Sweden
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26
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Affiliation(s)
- P Knöbl
- Department of Medicine 1, Medical University of Vienna, Vienna, Austria.
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27
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Abstract
Interaction between platelet and von Willebrand factor, a circulating adhesive glycoprotein, is essential for hemostasis under the high shear environments of arterioles and capillaries. If unregulated, this interaction may lead to unwarranted platelet thrombosis. ADAMTS13 (a disintegrin and metalloprotease with thrombospondin type 1 motif, number 13), a plasma zinc metalloprotease synthesized primarily in the stellate cells of the liver, cleaves shear stress-activated von Willebrand factor, thereby preventing the occurrence of von Willebrand factor-platelet interaction in the circulation. A profound deficiency of ADAMTS13, due to genetic mutations or autoimmune inhibition, results in intravascular von Willebrand factor platelet aggregation and widespread microvascular thrombosis characteristic of thrombotic thrombocytopenic purpura. Cloning of ADAMTS13 and structure-function analyses of the enzyme are leading to exciting advances in the diagnosis and therapy of this hitherto mysterious disease.
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Affiliation(s)
- Han-Mou Tsai
- Montefiore Medical Center and Albert Einstein College of Medicine, Unified Division of Hematology, Bronx, New York, NY, USA.
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