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Misasi R, Longo A, Recalchi S, Caissutti D, Riitano G, Manganelli V, Garofalo T, Sorice M, Capozzi A. Molecular Mechanisms of "Antiphospholipid Antibodies" and Their Paradoxical Role in the Pathogenesis of "Seronegative APS". Int J Mol Sci 2020; 21:ijms21218411. [PMID: 33182499 PMCID: PMC7665122 DOI: 10.3390/ijms21218411] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/30/2020] [Accepted: 11/06/2020] [Indexed: 02/06/2023] Open
Abstract
Antiphospholipid Syndrome (APS) is an autoimmune disease characterized by arterial and/or venous thrombosis and/or pregnancy morbidity, associated with circulating antiphospholipid antibodies (aPL). In some cases, patients with a clinical profile indicative of APS (thrombosis, recurrent miscarriages or fetal loss), who are persistently negative for conventional laboratory diagnostic criteria, are classified as "seronegative" APS patients (SN-APS). Several findings suggest that aPL, which target phospholipids and/or phospholipid binding proteins, mainly β-glycoprotein I (β-GPI), may contribute to thrombotic diathesis by interfering with hemostasis. Despite the strong association between aPL and thrombosis, the exact pathogenic mechanisms underlying thrombotic events and pregnancy morbidity in APS have not yet been fully elucidated and multiple mechanisms may be involved. Furthermore, in many SN-APS patients, it is possible to demonstrate the presence of unconventional aPL ("non-criteria" aPL) or to detect aPL with alternative laboratory methods. These findings allowed the scientists to study the pathogenic mechanism of SN-APS. This review is focused on the evidence showing that these antibodies may play a functional role in the signal transduction pathway(s) leading to thrombosis and pregnancy morbidity in SN-APS. A better comprehension of the molecular mechanisms triggered by aPL may drive development of potential therapeutic strategies in APS patients.
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Clarke LA, Brogan PA, Latchman DS, Isenberg DA, Ioannou Y, Giles IP, Rahman A, Pericleous C. Endothelial microparticle release is stimulated in vitro by purified IgG from patients with the antiphospholipid syndrome. Thromb Haemost 2017; 109:72-8. [DOI: 10.1160/th12-05-0346] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 10/09/2012] [Indexed: 11/05/2022]
Abstract
SummaryIgG antiphospholipid antibodies (aPL) exert direct effects on various cell types, contributing to the pathogenesis of thrombosis and pregnancy morbidity in patients with the antiphospholipid syndrome (APS). Some IgG samples from these patients activate endothelial cells (EC) in vitro as judged by surface expression of adhesion molecules such as E-selectin, which can promote thrombosis. Endothelial micro-particles (EMP), which themselves are potentially prothrombotic, are released by activated EC. Though elevated circulating EMP levels have been reported in patients with APS, it is not known whether these EMP are released due to a direct effect of aPL on the cells. We tested the effect of purified polyclonal IgG from patients with APS (APS-IgG) and healthy controls (HC-IgG) upon cultured human umbilical vein EC (HUVEC). HUVEC exposed to APS-IgG produced significantly more EMP than those exposed to HC-IgG (p=0.0036) and a greater proportion of these EMP carried surface E-selectin (6.2% ± 4.0 for APS-IgG vs. 3.4% ± 2.0 for HC IgG, p=0.0172). This study therefore demonstrates that purified polyclonal APS-IgG can drive EMP release. We propose that EMP generation may be a useful measure of aPL-mediated pathogenic effects upon EC.
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Factor Xa Mediates Calcium Flux in Endothelial Cells and is Potentiated by Igg From Patients With Lupus and/or Antiphospholipid Syndrome. Sci Rep 2017; 7:10788. [PMID: 28883515 PMCID: PMC5589732 DOI: 10.1038/s41598-017-11315-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 08/22/2017] [Indexed: 11/11/2022] Open
Abstract
Factor (F) Xa reactive IgG isolated from patients with antiphospholipid syndrome (APS) display higher avidity binding to FXa with greater coagulant effects compared to systemic lupus erythematosus (SLE) non APS IgG. FXa signalling via activation of protease-activated receptors (PAR) leads to increased intracellular calcium (Ca2+). Therefore, we measured alterations in Ca2+ levels in human umbilical vein endothelial cells (HUVEC) following FXa-mediated PAR activation and investigated whether FXa reactive IgG from patients with APS or SLE/APS- alter these responses. We observed concentration-dependent induction of Ca2+ release by FXa that was potentiated by APS-IgG and SLE/APS- IgG compared to healthy control subjects’ IgG, and FXa alone. APS-IgG and SLE/APS- IgG increased FXa mediated NFκB signalling and this effect was fully-retained in the affinity purified anti-FXa IgG sub-fraction. Antagonism of PAR-1 and PAR-2 reduced FXa-induced Ca2+ release. Treatment with a specific FXa inhibitor, hydroxychloroquine or fluvastatin significantly reduced FXa-induced and IgG-potentiated Ca2+ release. In conclusion, PAR-1 and PAR-2 are involved in FXa-mediated intracellular Ca2+ release in HUVEC and FXa reactive IgG from patients with APS and/or SLE potentiate this effect. Further work is required to explore the potential use of IgG FXa reactivity as a novel biomarker to stratify treatment with FXa inhibitors in these patients.
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Pericleous C, Ferreira I, Borghi O, Pregnolato F, McDonnell T, Garza-Garcia A, Driscoll P, Pierangeli S, Isenberg D, Ioannou Y, Giles I, Meroni PL, Rahman A. Measuring IgA Anti-β2-Glycoprotein I and IgG/IgA Anti-Domain I Antibodies Adds Value to Current Serological Assays for the Antiphospholipid Syndrome. PLoS One 2016; 11:e0156407. [PMID: 27253369 PMCID: PMC4890741 DOI: 10.1371/journal.pone.0156407] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 05/14/2016] [Indexed: 01/06/2023] Open
Abstract
Introduction Currently available clinical assays to detect antiphospholipid antibodies (aPL) test for IgG and IgM antibodies to cardiolipin (aCL) and β2-glycoprotein I (aβ2GPI). It has been suggested that testing for IgA aPL and for antibodies to Domain I (DI), which carries the key antigenic epitopes of β2GPI, could add value to these current tests. We performed an observational, multicenter cohort study to evaluate the utility of IgG, IgM and IgA assays to each of CL, β2GPI and DI in APS. Methods Serum from 230 patients with APS (n = 111), SLE but not APS (n = 119), and 200 healthy controls were tested for IgG, IgM and IgA aCL, aβ2GPI and aDI activity. Patients with APS were further classified into thrombotic or obstetric APS. Logistic regression and receiver operator characteristic analyses were employed to compare results from the nine different assays. Results All assays displayed good specificity for APS; IgG aCL and IgG aβ2GPI assays however, had the highest sensitivity. Testing positive for IgA aβ2GPI resulted in a higher hazard ratio for APS compared to IgM aβ2GPI. Positive IgG, IgM or IgA aDI were all associated with APS, and in subjects positive for aCL and/or aβ2GPI, the presence of aDI raised the hazard ratio for APS by 3–5 fold. IgG aCL, aβ2GPI, aDI and IgA aDI were associated with thrombotic but not obstetric complications in patients with APS. Conclusion Measuring IgG aDI and IgA aβ2GPI and aDI may be useful in the management of patients with APS, particularly thrombotic APS.
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Affiliation(s)
- Charis Pericleous
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom
| | - Isabel Ferreira
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom
| | - Orietta Borghi
- Laboratory of Immuno-rheumatology, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Francesca Pregnolato
- Laboratory of Immuno-rheumatology, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Thomas McDonnell
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom
| | - Acely Garza-Garcia
- Structural Biology, MRC National Institute for Medical Research, London, United Kingdom
| | - Paul Driscoll
- Structural Biology, MRC National Institute for Medical Research, London, United Kingdom
| | - Silvia Pierangeli
- Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - David Isenberg
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom
| | - Yiannis Ioannou
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom.,Arthritis Research UK Centre for Adolescent Rheumatology, UCL Hospital and Great Ormond Street Hospital, London, United Kingdom
| | - Ian Giles
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom
| | - Pier Luigi Meroni
- Laboratory of Immuno-rheumatology, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Anisur Rahman
- Centre for Rheumatology Research, Division of Medicine, University College London, London, United Kingdom
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Abstract
IgG antiphospholipid antibodies (aPL) against β2-glycoprotein I (β2GPI) can target any of its five domains; however, aPL against the N-terminal domain (anti-DI, aDI) are considered the most clinically relevant in the antiphospholipid syndrome (APS). Circulating levels of aDI are elevated in patients with APS compared with disease and healthy controls, and crucially aDI are prothrombotic in in vivo and in vitro models. In addition, human recombinant DI has been shown to abrogate aPL-induced thrombosis in vivo. Therefore, although the potential of utilizing DI for management of APS is not yet fully defined, there is promise that DI could prove valuable both as a diagnostic and therapeutic tool.
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Affiliation(s)
- C Pericleous
- Centre for Rheumatology Research, Division of Medicine, University College London, UK
| | - A Rahman
- Centre for Rheumatology Research, Division of Medicine, University College London, UK
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Rodríguez-García V, Ioannou Y, Fernández-Nebro A, Isenberg DA, Giles IP. Examining the prevalence of non-criteria anti-phospholipid antibodies in patients with anti-phospholipid syndrome: a systematic review. Rheumatology (Oxford) 2015; 54:2042-50. [DOI: 10.1093/rheumatology/kev226] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Indexed: 11/13/2022] Open
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Artim-Esen B, Pericleous C, Mackie I, Ripoll VM, Latchman D, Isenberg D, Rahman A, Ioannou Y, Giles I. Anti-factor Xa antibodies in patients with antiphospholipid syndrome and their effects upon coagulation assays. Arthritis Res Ther 2015; 17:47. [PMID: 25890027 PMCID: PMC4365552 DOI: 10.1186/s13075-015-0568-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 02/19/2015] [Indexed: 02/02/2023] Open
Abstract
Introduction The aim of this study was to examine the prevalence and functional effects of antibodies directed against Factor (F)Xa and other serine proteases (SP) in patients with antiphospholipid syndrome (APS). Methods Serum from patients with APS (n = 59), systemic lupus erythematosus (SLE; n = 106), other autoimmune rheumatic disease (ARD; n = 63) and 40 healthy controls (HC) were tested for IgG activity against thrombin (Thr), FXa, FVIIa, phosphatidylserine (PS)/FXa and antithrombin (AT)-III by enzyme-linked immunosorbent assay (ELISA). Anti-FXa positive IgG were purified to measure their avidity by chaotropic ELISA and functional effects upon clotting time (FXa-ACT) and FXa enzymatic activity (± AT-III). Results Anti-FXa IgG were found in patients with SLE (49.1%) and APS (33.9%) (P <0.05) but not in ARD controls and HC. In contrast, anti-Thr and anti-PS/FXa IgG were identified in other ARD and anti-FVIIa IgG were low in all groups. The avidity of APS-IgG to FXa was significantly higher than SLE-IgG (P <0.05). Greatest prolongation of FXa-ACT was observed with APS-IgG and greatest inhibitory effect upon FXa enzymatic activity was found with APS-IgG followed by SLE-IgG compared to HC-IgG. ATIII inhibition of FXa was significantly reduced by APS-IgG compared with HC and SLE (P <0.05) and did not correlate with binding to AT-III. Conclusion APS anti-FXa IgG have higher avidity to FXa and greater effects upon the enzymatic and coagulant activity of FXa compared with SLE anti-FXa IgG. Further studies of anti-FXa antibodies in APS, SLE and other non-autoimmune thrombotic disease cohorts are now required to evaluate whether targeting FXa with selective inhibitors in patients bearing anti-FXa antibodies may be an effective treatment strategy.
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Affiliation(s)
- Bahar Artim-Esen
- Centre for Rheumatology Research, Rayne Institute, University College London, London, UK. .,Division of Rheumatology, Department of Internal Medicine, Istanbul Faculty of Medicine, Istanbul University, 34098 Çapa, Fatih, Istanbul, Turkey.
| | - Charis Pericleous
- Centre for Rheumatology Research, Rayne Institute, University College London, London, UK.
| | - Ian Mackie
- Haemostasis Research Unit, Department of Haematology, University College London, London, UK.
| | - Vera M Ripoll
- Centre for Rheumatology Research, Rayne Institute, University College London, London, UK.
| | - David Latchman
- Birkbeck, University of London, Malet Street, London, WC1E 6JF, USA.
| | - David Isenberg
- Centre for Rheumatology Research, Rayne Institute, University College London, London, UK.
| | - Anisur Rahman
- Centre for Rheumatology Research, Rayne Institute, University College London, London, UK.
| | - Yiannis Ioannou
- Arthritis Research UK Centre for Adolescent Rheumatology, University College London, UCL Hospital and Great Ormond Street Hospital, London, UK.
| | - Ian Giles
- Centre for Rheumatology Research, Rayne Institute, University College London, London, UK.
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Pericleous C, Ruiz-Limón P, Romay-Penabad Z, Marín AC, Garza-Garcia A, Murfitt L, Driscoll PC, Latchman DS, Isenberg DA, Giles I, Ioannou Y, Rahman A, Pierangeli SS. Proof-of-concept study demonstrating the pathogenicity of affinity-purified IgG antibodies directed to domain I of β2-glycoprotein I in a mouse model of anti-phospholipid antibody-induced thrombosis. Rheumatology (Oxford) 2014; 54:722-7. [PMID: 25273993 PMCID: PMC4372675 DOI: 10.1093/rheumatology/keu360] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE IgG aPL against domain I of β2-glycoprotein I (β2GPI) [anti-DI (aDI)] is associated with the pathogenesis of APS, an autoimmune disease defined by thrombosis and pregnancy morbidity. To date, however, no study has demonstrated direct pathogenicity of IgG aDI in vivo. In this proof-of-concept study, we designed a novel system to affinity purify polyclonal aDI aPL in order to assess its prothrombotic ability in a well-characterized mouse microcirculation model for APS. METHODS Two polyclonal IgG fractions were isolated from serum of a patient with APS, both with high aPL activity but differing in aDI activity (aDI-rich and aDI-poor). These IgG fractions were tested for their pathogenic ability in an in vivo mouse model of thrombosis. Male CD1 mice were injected intraperitoneally with either aDI-rich or aDI-poor IgG; as a control, IgG isolated from healthy serum was used. A pinch injury was applied to the right femoral vein and thrombus dynamics and tissue factor activity in isolated tissue were evaluated. RESULTS Both aDI-rich and aDI-poor IgG retained aCL and anti-β2GPI activity, while only aDI-rich IgG displayed high aDI activity, as defined by our in-house cut-offs for positivity in each assay. aDI-rich IgG induced significantly larger thrombi in vivo compared with aDI-poor IgG (P < 0.0001). Similarly, aDI-rich IgG significantly enhanced the procoagulant activity of carotid artery endothelium and peritoneal macrophages isolated from experimental animals (P < 0.01). CONCLUSION These data directly demonstrate that the ability to cause thrombosis in vivo is concentrated in the aDI fraction of aPL.
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Affiliation(s)
- Charis Pericleous
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - Patricia Ruiz-Limón
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - Zurina Romay-Penabad
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - Ana Carrera Marín
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - Acely Garza-Garcia
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - Lucy Murfitt
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - Paul C Driscoll
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - David S Latchman
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - David A Isenberg
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - Ian Giles
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - Yiannis Ioannou
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK. Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - Anisur Rahman
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK
| | - Silvia S Pierangeli
- Centre for Rheumatology Research, Division of Medicine, University College London, London, UK, Division of Rheumatology, Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX, USA, Structural Biology, Medical Research Council National Institute for Medical Research and Arthritis Research UK Centre for Adolescent Rheumatology, University College London Hospital and Great Ormond Street Hospital, London, UK.
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Du VX, Kelchtermans H, de Groot PG, de Laat B. From antibody to clinical phenotype, the black box of the antiphospholipid syndrome: Pathogenic mechanisms of the antiphospholipid syndrome. Thromb Res 2013; 132:319-26. [DOI: 10.1016/j.thromres.2013.07.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 07/26/2013] [Accepted: 07/26/2013] [Indexed: 11/30/2022]
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Chuang YC, Lin YS, Liu HS, Wang JR, Yeh TM. Antibodies against thrombin in dengue patients contain both anti-thrombotic and pro-fibrinolytic activities. Thromb Haemost 2013; 110:358-65. [PMID: 23740201 DOI: 10.1160/th13-02-0149] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Accepted: 05/02/2013] [Indexed: 11/05/2022]
Abstract
Dengue virus (DENV) infection may result in severe life-threatening Dengue haemorrhagic fever (DHF). The mechanisms causing haemorrhage in those with DHF are unclear. In this study, we demonstrated that antibodies against human thrombin were increased in the sera of Dengue patients but not in that of patients infected with other viruses. To further characterise the properties of these antibodies, affinity-purified anti-thrombin antibodies (ATAs) were collected from Dengue patient sera by thrombin and protein A/L affinity columns. Most of the ATAs belonged to the IgG class and recognized DENV nonstructural protein 1 (NS1). In addition, we found that dengue patient ATAs also cross-reacted with human plasminogen (Plg). Functional studies in vitro indicated that Dengue patient ATAs could inhibit thrombin activity and enhance Plg activation. Taken together, these results suggest that DENV NS1-induced thrombin and Plg cross-reactive antibodies may contribute to the development of haemorrhage in patients with DHF by interfering with coagulation and fibrinolysis.
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Affiliation(s)
- Yung-Chun Chuang
- Department of Medical Laboratory Science and Biotechnology, Medical College, National Cheng Kung University, Tainan, Taiwan.
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Lambrianides A, Turner-Stokes T, Pericleous C, Ehsanullah J, Papadimitraki E, Poulton K, Ioannou Y, Lawrie A, Mackie I, Chen P, Latchman D, Isenberg D, Rahman A, Giles I. Interactions of human monoclonal and polyclonal antiphospholipid antibodies with serine proteases involved in hemostasis. ACTA ACUST UNITED AC 2013; 63:3512-21. [PMID: 21739425 PMCID: PMC3494292 DOI: 10.1002/art.30525] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE To characterize the interaction between procoagulant and/or anticoagulant serine proteases and human monoclonal IgG antiphospholipid antibodies (aPL) and polyclonal IgG derived from patients with the antiphospholipid syndrome (APS). METHODS Five human monoclonal IgG with small differences in their sequences were tested for binding to protein C, activated protein C, plasmin, factor VIIa (FVIIa), FIX, FIXa, and FXII. Serum levels of antithrombin and anti-activated protein C were compared in 32 patients with APS, 29 patients with systemic lupus erythematosus (SLE), and 22 healthy controls. Purified polyclonal IgG derived from APS patients with elevated levels of serum antithrombin antibodies was also tested for its functional effects on thrombin and antithrombin activity. RESULTS Studies of monoclonal antibodies showed that sequence changes in human aPL are important in determining their ability to bind procoagulant and anticoagulant/fibrinolytic serine proteases. Mean IgG antithrombin levels were significantly elevated in patients with APS and in SLE patients with aPL but no APS (SLE/aPL+) compared to healthy controls, but anti-activated protein C levels were not increased in these patients. Moreover, IgG purified from patients with APS displayed higher avidity for thrombin and significantly inhibited antithrombin inactivation of thrombin compared with IgG from SLE/aPL+ patients. CONCLUSION High-avidity antithrombin antibodies, which prevent antithrombin inactivation of thrombin, distinguish patients with APS from SLE/aPL+ patients, and thus may contribute to the pathogenesis of vascular thrombosis in APS.
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Examining How Antiphospholipid Antibodies Activate Intracellular Signaling Pathways: A Systematic Review. Semin Arthritis Rheum 2012; 41:720-36. [DOI: 10.1016/j.semarthrit.2011.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 09/14/2011] [Accepted: 09/21/2011] [Indexed: 01/23/2023]
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Pericleous C, Miles J, Esposito D, Garza-Garcia A, Driscoll PC, Lambrianides A, Latchman D, Isenberg D, Rahman A, Ioannou Y, Giles I. Evaluating the conformation of recombinant domain I of β(2)-glycoprotein I and its interaction with human monoclonal antibodies. Mol Immunol 2011; 49:56-63. [PMID: 21899894 PMCID: PMC3268385 DOI: 10.1016/j.molimm.2011.07.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 07/27/2011] [Accepted: 07/27/2011] [Indexed: 11/29/2022]
Abstract
Pathogenic antiphospholipid antibodies (aPL) cause the antiphospholipid syndrome (APS) by interacting with domain I (DI) of beta-2-glycoprotein I (β2GPI). The aPL/β2GPI complex then exerts pathogenic effects on target cells. We previously described periplasmic bacterial expression of native and mutated variants of DI, and reported the presence of immunodominant epitopes at positions 8–9 (D8/D9) and position 39 (R39). Mutations at these positions strongly influenced the ability of recombinant DI to bind patient-derived IgG aPL and to inhibit pathogenic effects of these aPL in a mouse model of APS. We now describe an improved cytoplasmic bacterial expression system allowing higher yield of DI. We demonstrate that the nuclear magnetic resonance (NMR) spectra of a 15N,13C-isotope-labelled sample of the recombinant DI protein exhibit properties consistent with the structure of DI in crystal structure of intact β2GPI. Mutations at D8/D9 and R39 had limited impact on the NMR spectrum of DI indicating maintenance of the overall fold of the DI domain. We investigated interactions between five variants of DI and ten monoclonal human IgG antibodies, all derived from the IgG aPL antibody IS4 by sequence manipulation and in vitro expression. Arginine residues at positions 100 and 100g in IS4VH CDR3 play a particularly important role in binding to DI, but this is unlikely to be due to electrostatic interactions with negatively charged amino acids on DI. Both the strength of binding to DI and the ability to discriminate different DI variants varies between the different IgG antibodies tested. There was no simple relationship between these binding properties and antibody pathogenicity.
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Affiliation(s)
- Charis Pericleous
- Centre for Rheumatology, Division of Medicine, University College London, London WC1E 6JF, UK.
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Prinz N, Häuser F, Lorenz M, Lackner KJ, von Landenberg P. Structural and functional characterization of a human IgG monoclonal antiphospholipid antibody. Immunobiology 2011; 216:145-51. [DOI: 10.1016/j.imbio.2010.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 04/22/2010] [Accepted: 05/02/2010] [Indexed: 10/19/2022]
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Abstract
It is generally accepted that the major autoantigen for antiphospholipid antibodies (aPL) in the antiphospholipid syndrome (APS) is beta(2)-glycoprotein I (beta(2)GPI). However, a recent study has revealed that some aPL bind to certain conformational epitope(s) on beta(2)GPI shared by the homologous enzymatic domains of several serine proteases involved in hemostasis and fibrinolysis. Importantly, some serine protease-reactive aPL correspondingly hinder anticoagulant regulation and resolution of clots. These results extend several early findings of aPL binding to other coagulation factors and provide a new perspective about some aPL in terms of binding specificities and related functional properties in promoting thrombosis. Moreover, a recent immunological and pathological study of a panel of human IgG monoclonal aPL showed that aPL with strong binding to thrombin promote in vivo venous thrombosis and leukocyte adherence, suggesting that aPL reactivity with thrombin may be a good predictor for pathogenic potentials of aPL.
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Affiliation(s)
- Pojen P Chen
- Department of Medicine, Division of Rheumatology, University of California, Los Angeles, 1000 Veteran Avenue, Los Angeles, CA 90095, USA.
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Lambrianides A, Giles IP. Use of monoclonal antibodies to dissect specificity and pathogenesis of antiphospholipid antibodies. Lupus 2010; 19:359-64. [PMID: 20353970 DOI: 10.1177/0961203309360809] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Monoclonal antiphospholipid antibodies (aPL) have been utilized to dissect the relationship between their sequence, structure, binding and biological properties relevant to the pathogenesis of the antiphospholipid syndrome. In particular, sequence analysis of aPL has highlighted the clustering of certain amino acid residues in the antigen contact sites of their heavy and light chains. Therefore, these sequence motifs are likely to be important in determining aPL binding properties and their pathogenic effects. Experiments, however, using monoclonal aPL engineered to contain specific point mutations in their sequence which alter their ability to bind relevant antigens have shown that these alterations in binding are not directly mirrored by their pathogenic effects. In this review we focus on work carried out by others and ourselves using monoclonal antibodies with specific binding properties to extend our knowledge of the non-linear structure-binding-function relationship of aPL.
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Affiliation(s)
- A Lambrianides
- Medical Molecular Biology Unit, Institute of Child Health and Centre of Rheumatology, University College London, London, UK
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