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Hulstein JJJ, Lenting PJ, de Laat B, Derksen RHWM, Fijnheer R, de Groot PG. β2-Glycoprotein I inhibits von Willebrand factor–dependent platelet adhesion and aggregation. Blood 2007; 110:1483-91. [PMID: 17488878 DOI: 10.1182/blood-2006-10-053199] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractPatients with antiphospholipid syndrome are characterized by the association of thrombosis or pregnancy morbidity and the presence of antiphospholipid autoantibodies. Particularly, anti-β2-glycoprotein (β2 GPI) autoantibodies correlate with thrombosis, suggesting an antibody-induced gain of prothrombotic function and/or an antibody-induced loss of antithrombotic function of β2 GPI. In the search for potential antithrombotic properties of β2 GPI, we found that β2 GPI inhibits von Willebrand factor (VWF)–induced platelet aggregation. In addition, platelet adhesion to a VWF-coated surface was decreased by 50% in the presence of β2 GPI (P < .03). β2 GPI binds to the A1 domain of VWF but preferably when the A1 domain is in its active glycoprotein Ibα-binding conformation. Anti-β2 GPI antibodies isolated from a subset of antiphospholipid syndrome patients neutralized the β2 GPI-VWF interactions and thus the inhibitory activity of β2 GPI. In comparison to healthy individuals, the amounts of active VWF in circulation were increased 1.5-fold (P < .001) in patients positive for lupus anticoagulant (LAC) due to anti-β2 GPI antibodies. Thus, β2 GPI is a biologically relevant inhibitor of VWF function by interfering with VWF-dependent platelet adhesion. Anti-β2 GPI autoantibodies neutralize this inhibitory function and are associated with increased levels of active VWF. This mode of action could contribute to the thrombosis and consumptive thrombocytopenia observed in patients with anti-β2 GPI antibodies.
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Affiliation(s)
- Janine J J Hulstein
- Laboratory for Thrombosis and Haemostasis, Department of Clinical Chemistry and Haematology, University Medical Centre Utrecht, Utrecht, the Netherlands
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Abstract
Nanomedicine is a global business enterprise. Industry and governments clearly are beginning to envision nanomedicine's enormous potential. A clear definition of nanotechnology is an issue that requires urgent attention. This problem exists because nanotechnology represents a cluster of technologies, each of which may have different characteristics and applications. Although numerous novel nanomedicine-related applications are under development or nearing commercialization, the process of converting basic research in nanomedicine into commercially viable products will be long and difficult. Although realization of the full potential of nanomedicine may be years or decades away, recent advances in nanotechnology-related drug delivery, diagnosis, and drug development are beginning to change the landscape of medicine. Site-specific targeted drug delivery and personalized medicine are just a few concepts that are on the horizon.
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Affiliation(s)
- K John Morrow
- Newport Biotechnology Consultants, 625 Washington Avenue, Newport, KY 41071, USA
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53
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Jilma-Stohlawetz P, Jilma B, Mannhalter C, Bencur P, Pabinger I, Vormittag R, Dunkler D, Panzer S. Platelet glycoprotein Ibalpha polymorphisms and function evaluated by the platelet function analyzer PFA-100 in patients with lupus anticoagulant: the association with thromboembolic disease. Ann Hematol 2007; 86:719-25. [PMID: 17634946 DOI: 10.1007/s00277-007-0341-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2007] [Accepted: 06/26/2007] [Indexed: 11/26/2022]
Abstract
Lupus anticoagulants (LA) are a surrogate marker for the risk of thromboembolic disease (TE). However, not all individuals with LA acquire TE, and it is desirable to distinguish those at risk for TE from those without. Platelets polymorphisms may contribute to the risk of TE, mainly those of glycoprotein (GP)Ibalpha: these are the variable number of tandem repeats (VNTR) and a dimorphism in the Kozak region, which affect platelet plug formation in healthy individuals under high shear stress rates. We determined polymorphisms within the GPIbalpha in individuals with persistent LA and a history of TE (LA/TE+) and in those without TE (LA/TE-). Further, we measured platelet function, as estimated by the collagen-epinephrine closure time (CEPI-CT) of the platelet function analyzer PFA-100 and compared all data with healthy controls. There was no difference of the VNTR alleles compared to healthy controls. The (-5)C allele of the Kozak dimorphism was significantly more frequent in LA patients compared to controls (p = 0.04), as a result of its increased frequency in LA/TE+ (vs controls p = 0.04), but there was no difference between LA/TE+ and LA/TE-. The increased frequency of the (-5)C allele resulted in an overrepresentation of (-5)TC genotype in the LA/TE+ group (p = 0.02) but not in a subgroup of 18 patients with arterial disease. The CEPI-CT of the PFA-100 was shorter in LA/TE+ than in LA/TE- (p = 0.044), but this difference did not persist after exclusion of patients with low platelet counts or low ristocetin cofactor activity. Unlike in healthy individuals, the CEPI-CT was not related to any Kozak dimorphism, neither in LA/TE-, nor in LA/TE+. Thus, the Kozak dimorphism may just contribute to stronger factors disposing individuals with LA towards TE without any discernible effect on their in vitro platelet function estimated by the PFA-100.
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Affiliation(s)
- Petra Jilma-Stohlawetz
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
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Rolla R, Vidali M, Serino R, Pergolini P, Albano E, Bellomo G. Antibodies against oxidized phospholipids in laboratory tests exploring lupus anti-coagulant activity. Clin Exp Immunol 2007; 149:63-9. [PMID: 17488295 PMCID: PMC1942029 DOI: 10.1111/j.1365-2249.2007.03404.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Lupus anti-coagulants (LA) are a variety of anti-phospholipid antibodies characterized by their capacity to interfere with phospholipid-dependent coagulation assays. LA are increasingly recognized as important predictors of thrombosis. However, the antigen specificity of LA is still poorly characterized. Growing evidence indicates that oxidized phospholipids are among the targets of anti-phospholipid antibodies. This prompted us to investigate the role of IgG directed against different oxidized phospholipids in 164 subjects without clotting factor defects that were tested for the presence of LA using a LA-sensitive activate partial thromboplastin time (aPTT-FSL) and a screening/confirmation assay based on diluted Russell's viper venom test (dRVVT-PL). The response to aPTT-FSL was significantly (P < 0.0005) associated with high titres of IgG against oxidized phosphatidylserine, phosphatidylethanolamine and phosphatidylinositol, whereas positivity to dRVVT-PL was associated with the elevation of IgG against oxidized phosphatidylserine, phosphatidylcholine, phosphatidylethanolamine (P < 0.0005) and phosphatidylinositol (P < 0.01). No difference in reactivity against oxidized cardiolipin was evident between the different groups. Positivity to the dRVVT-PL test was also associated significantly (P < 0.005) with the elevation of anti-cardiolipin and anti-beta(2)-glycoprotein-1 IgG. However, stepwise logistic regression demonstrated that IgG recognizing oxidized phosphatidylethanolamine and oxidized phosphatidylcholine were the only independent predictors of the response to dRVVT-PL assay, while IgG recognizing oxidized phosphatidylethanolamine and oxidized phosphatidylinositol were independent predictors of the response to aPTT-FSL test. In conclusion, autoantibodies against defined oxidized phospholipids are independent predictors of LA detection by aPTT-FSL or dRVVT-PL assays and might contribute to the variability often observed in the responses to the functional tests detecting LA.
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Affiliation(s)
- R Rolla
- Department of Medical Sciences, University A. Avogadro of East Piedmont and Interdepartmental Research Centre for Autoimmune Diseases, Novara, Italy
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Metzger J, von Landenberg P, Kehrel M, Buhl A, Lackner KJ, Luppa PB. Biosensor analysis of beta2-glycoprotein I-reactive autoantibodies: evidence for isotype-specific binding and differentiation of pathogenic from infection-induced antibodies. Clin Chem 2007; 53:1137-43. [PMID: 17434906 DOI: 10.1373/clinchem.2006.079632] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND For the laboratory diagnosis of the antiphospholipid syndrome (APS) we developed a biosensor with the ability to distinguish between disease-relevant anti-beta2-glycoprotein I (beta2GPI) autoantibodies (anti-beta2GPI) and pathogen-specific beta2GPI cross-reactive antibodies that occur transiently during infections. METHODS We used a surface plasmon resonance (SPR) biosensor device. For the detection of anti-beta2GPI in serum samples, affinity-purified human beta2GPI was covalently attached to a functionalized n-alkanethiol self-assembling monolayer on the biosensor chip. After verifying the specificity of the biosensor system with a panel of monoclonal antibodies to beta2GPI, we analyzed sera from healthy donors and patients suffering from APS, systemic lupus erythematosus (SLE), syphilis, or parvovirus B19 infections. The SPR results were compared with beta2GPI-specific ELISA. RESULTS Using the SPR biosensor, we recorded antigen binding curves with response levels in the range of 50-500, resonance units (RU) for anti-beta2GPI ELISA-positive APS patient sera. The amplitudes of the antiphospholipid antibody (APL) responses in the biosensor correlated with the overall IgG and IgM anti-beta2GPI ELISA titers with a correlation coefficient of 0.87. Moreover, we observed immunoglobulin isotype-specific association and dissociation profiles for APL binding of different APS patient sera to the biosensor-immobilized beta2GPI. In contrast to APS patient samples, no significant anti-beta2GPI binding (response levels <35 RU) was observed in samples from healthy individuals or from patients suffering from SLE, syphilis, or parvovirus B19 infection. CONCLUSIONS The SPR biosensor system enables specific detection of APS-associated beta2GPI-reactive APL and differentiation from beta2GPI cross-reactive antibodies that occur frequently during acute infections. The established association/dissociation plot for anti-beta2GPI responses in APS patient sera gives additional information regarding the influence of anti-beta2GPI IgG and IgM isotype distribution.
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Affiliation(s)
- Jochen Metzger
- Institute of Clinical Chemistry and Pathobiochemistry, Klinikum Rechts der Isar der TU München, München, Germany
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Sailer T, Vormittag R, Zoghlami C, Koder S, Quehenberger P, Male C, Pabinger I. The clinical significance of anti-prothrombin antibodies for risk assessment of thromboembolism in patients with lupus anticoagulant. Thromb Res 2007; 120:295-302. [PMID: 17328943 DOI: 10.1016/j.thromres.2007.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 12/30/2006] [Accepted: 01/01/2007] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Thromboembolism is a common manifestation of lupus anticoagulant (LA), however only a subgroup of LA-patients is affected by thrombosis. Study objective was to investigate whether anti-prothrombin antibodies can identify LA-patients at increased risk for thrombosis. MATERIALS AND METHODS In total 79 patients, 50 with (42 men/8 women) and 29 without thrombosis (21 men/8 women), were investigated for their presence of anti-prothrombin IgG and IgM antibodies using assays from two different manufacturers (Aeskulisa=assay I, CoaChrom=assay II). RESULTS The prevalence of elevated levels of anti-prothrombin IgG, IgM as well as IgG and/or IgM antibodies was 66% [assayI] (36% [assayII]), 38% (24%) and 72% (50%) in patients with thrombosis and 55% (24%), 28% (28%) and 66% (41%) in patients without thrombosis, respectively. Neither anti-prothrombin IgG or IgM nor IgG and/or IgM antibodies were found to indicate an increased risk for thrombosis. In the subgroup of patients with arterial or venous thrombosis there was also no association between anti-prothrombin antibodies and thrombosis. The comparison of median levels of IgG and IgM anti-prothrombin antibodies between patients with and without thrombosis yielded a borderline statistically significant difference only for anti-prothrombin IgG antibodies by using assay II (p=0.033), all other comparisons were not statistically significant. CONCLUSIONS In conclusion, presence of anti-prothrombin antibodies was not associated with thromboembolism in LA-patients.
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Affiliation(s)
- Thomas Sailer
- Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Austria
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Devreese KMJ. Evaluation of a new silica clotting time in the diagnosis of lupus anticoagulants. Thromb Res 2007; 120:427-38. [PMID: 17156825 DOI: 10.1016/j.thromres.2006.10.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Revised: 10/16/2006] [Accepted: 10/16/2006] [Indexed: 10/23/2022]
Abstract
INTRODUCTION A new commercial silica clotting time (SCT), the HemosIL SCT assay (Instrumentation Laboratory, Milan, Italy) was evaluated in the laboratory diagnosis of lupus anticoagulants (LAC). This integrated test system for screening and confirmation was compared with the frequently used aPTT-based PTT-LA and Staclot-LA (Diagnostica Stago, Asnières, France) in a patient population investigated for LAC and in a subpopulation who met the clinical criteria for antiphospholipid syndrome (APS). MATERIALS AND METHODS 201 samples were analysed with the HemosIL SCT assay. Own reference values were calculated. Results are expressed as measured clotting times in seconds or as normalised ratios. RESULTS SCT screen and PTT-LA had a sensitivity of, 61.1% and 63.8%, respectively. Normalising the results gained sensitivity up to 72.2% and 90%, respectively. The confirmation SCT and the Staclot-LA had a sensitivity of 30.6% and 63.9% with a specificity of 86.7% and 100%, respectively. Sensitivity of SCT for detecting LAC in clinical criteria positive patients was lower compared to aPTT and dRVVT (45.8% versus 66.7% and 65%). Combination of SCT/dRVVT and aPTT/dRVVT gave a sensitivity of 51.2% and 63.6%, with a specificity of 50.0% and 52.3%, respectively. CONCLUSIONS In comparison with PTT-LA as screening test, the SCT screen shows an acceptable sensitivity. However, the HemosIL SCT assay including the confirmation step, has a much lower sensitivity in the diagnosis of LAC in comparison with the Staclot-LA test. Combining the HemosIL SCT assay with dRVVT results in a better sensitivity, although lower than the combined aPTT/dRVVT based method as usually performed in our lab.
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Affiliation(s)
- Katrien M J Devreese
- Coagulation Laboratory, Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital De Pintelaan, 185 (2P8) B-9000 Gent Belgium
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Devreese KMJ. A functional coagulation test to identify anti-β2-glycoprotein I dependent lupus anticoagulants. Thromb Res 2007; 119:753-9. [PMID: 16842842 DOI: 10.1016/j.thromres.2006.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Revised: 05/11/2006] [Accepted: 06/07/2006] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Lupus Anticoagulants (LAC) activity due to beta(2)-glycoprotein I (beta(2)GPI) antibodies shows a high correlation with thrombotic events. Since the binding of beta(2)GPI antibodies to phospholipids may be influenced by the final calcium chloride (CaCl(2)) concentration a discrimination between beta(2)GPI dependent LAC and beta(2)GPI independent LAC could be possible using clotting tests with various CaCl(2) concentrations and making them this way more sensitive to the presence of beta(2)GPI antibodies. MATERIALS AND METHODS I evaluated the effect of 5 mM, 8.3 mM, 10.3 mM and 17.9 mM final CaCl(2) concentration in a commonly used screening test for LAC, the PTT-LA, on LAC positive patients with and without beta(2)GPI antibodies. RESULTS Mean coagulation times of LAC patients negative for beta(2)GPI antibodies were significant shorter with 5 mM CaCl(2) in comparison with 8.3 mM and 10 mM (P<0.05 and P<0.01, respectively). In the LAC patients with positive beta(2)GPI antibodies no significant difference at 5 mM CaCl(2), 8.3 mM or 10 mM was observed. Mean coagulation times at 5 mM CaCl(2) were significant higher (P=0.003) in patients positive for beta(2)GPI antibodies than in patients negative for beta(2)GPI antibodies. CONCLUSION The most remarkable observation was that the coagulation time, measured by PTT-LA at low final CaCl(2) concentration, is much more prolonged in the LAC positive beta(2)GPI antibody positive patients than in the LAC positive beta(2)GPI antibody negative patients. Thus, the competition with clotting factors for binding on phospholipids is stronger for beta(2)GPI antibodies than for other antibodies and explains the longer coagulation times in the presence of beta(2)GPI antibodies.
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Affiliation(s)
- Katrien M J Devreese
- Coagulation Laboratory, Laboratory for Clinical Biology, Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital, De Pintelaan, 185 (2P8), B-9000 Ghent, Belgium.
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Devreese KM. Evaluation of new commercial enzyme-linked immunosorbent assay kits in the laboratory diagnosis of antiphospholipid syndrome in view of the revised classification criteria of the antiphospholipid syndrome. Blood Coagul Fibrinolysis 2006; 17:651-9. [PMID: 17102652 DOI: 10.1097/01.mbc.0000252600.09777.2b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Amendments to the Sapporo criteria for the diagnosis of the antiphospholipid syndrome (APS) have recently be published and include testing for the presence of IgG and IgM beta2-glycoprotein I (beta(2)GPI) antibodies. The Asserachrom Antiphospholipid antibodies line (Diagnostica Stago) with a monoclonal based standardisation, was evaluated in a Lupus anticoagulant (LAC) positive (n = 138) and a LAC negative (n = 134) populations. The ELISA line consists of the Asserachrom APA Screen, the Asserachrom APA IgG,M and the Asserachrom anti-beta(2)GPI IgG and IgM. Anti-prothrombin antibodies (APT), not being included in the updated laboratory criteria, have been tested by the Asserachrom anti-prothrombin IgG,M. Imprecision characteristics showed coefficients of variation (CV) ranging from 4.9% to 13.9%. Cut-off values were calculated with the 99 percentile. The Asserachrom APA Screen showed 1,5% false positive and 0,7% false negative results in correlation with the Asserachrom APA IgG,M. 14.7% of the patients were positive for beta2GPI antibodies, 30,0% of them showed a negative Asserachrom APA Screen. beta(2)GPI antibodies may be the only test positive in a minority of patients, so the Asserachrom APA Screen and the Asserachrom anti-beta(2)GPI IgG and IgM should be performed in parallel when APS is suspected. LAC and APA assays, however, remain essential in the laboratory diagnosis of APS.
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Affiliation(s)
- Katrien Mj Devreese
- Coagulation Laboratory, Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital, Ghent, Belgium.
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Endler G, Marsik C, Jilma B, Schickbauer T, Vormittag R, Wagner O, Mannhalter C, Rumpold H, Pabinger I. Anti-cardiolipin antibodies and overall survival in a large cohort: preliminary report. Clin Chem 2006; 52:1040-4. [PMID: 16574758 DOI: 10.1373/clinchem.2005.063925] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Anti-cardiolipin antibodies have been associated with both arterial and venous thrombosis, but their overall impact on all-cause or vascular mortality is unknown. In this study, we evaluated the influence of anti-cardiolipin antibodies on all-cause and vascular mortality. METHODS All individuals who fulfilled the inclusion criteria (completeness of data, no admission from an intensive care unit, unique identification with name and date of birth) and whose anti-cardiolipin antibodies were measured between October 2002 and February 2004 were included in this study (n = 4756; 64% female; median age, 46 years). Death/survival and cause of death were obtained from the Austrian Death Registry. The median observation period was 1.5 years, and the study comprised 7189 person-years. RESULTS During the study period, 184 patients (3.9%) died. There were no associations between either anti-cardiolipin IgM or IgG antibodies and both vascular death and noncancer mortality as outcome variables in a Cox regression analysis adjusted for age and sex. In contrast, the risk of cancer-related mortality was increased 2.6-fold. CONCLUSIONS Anti-cardiolipin antibodies are associated with cancer mortality, likely as an epiphenomenon of malignancy, but they are not predictive of vascular mortality or noncancer mortality. Hence, although a clear association between anti-cardiolipin antibodies and (mostly nonfatal) vascular events has been described in the literature, our data indicate that this finding is not necessarily associated with an increase in vascular mortality.
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Affiliation(s)
- Georg Endler
- Institute of Medical and Chemical Laboratory Diagnostics, Department of Clinical Pharmacology, Division of Haematology and Immunology, Medical University of Vienna, Vienna, Austria
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Pengo V. Anti-beta2-glycoprotein I antibody testing in the laboratory diagnosis of antiphospholipid syndrome. J Thromb Haemost 2005; 3:1158-9. [PMID: 15946203 DOI: 10.1111/j.1538-7836.2005.01444.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- V Pengo
- Department of Cardiac Thoracic and Vascular Sciences, Clinical Cardiology, Thrombosis Center, University of Padua School of Medicine, Padua, Italy.
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