Detection of Lupus-Like Anticoagulants by an Enzyme-Linked Immunosorbent Assay Using a Partial Thromboplastin as Antigen; A Comparative Study

Arnout, Jozef; Huybrechts, Erwin; Vanrusselt, M; Falcon, C; Vermylen, Jos

doi:10.1055/s-0038-1647148

Cited by 9 publications

(4 citation statements)

References 18 publications

(22 reference statements)

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“…5,6 However, the so-called anticardiolipin antibodies (aCLs) also bind to other negatively charged PLs, such as phosphatidylserine. 7 Affinity purification of aCLs revealed that aCL binding to cardiolipin depends on a plasma protein, ␤ 2 -glycoprotein I (␤ 2 GPI). [8][9][10] It is now generally accepted that autoimmune aPLs are directed against proteins binding to anionic PL surfaces rather than against PLs themselves, the major protein targets appearing to be ␤ 2 GPI and prothrombin.…”

Section: Introductionmentioning

confidence: 99%

Thrombogenicity of β2-glycoprotein I–dependent antiphospholipid antibodies in a photochemically induced thrombosis model in the hamster

Jankowski

Vreys

Wittevrongel

et al. 2003

Blood

166

126

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We previously showed that ␤ 2 -glycoprotein I (␤ 2 GPI)-dependent lupus anticoagulants (LAs) form bivalent antigen-antibody complexes with high affinity for phospholipids; these complexes are responsible for their in vitro anticoagulant effect. We now studied the role of these bivalent complexes in arterial thrombosis in the hamster. Three monoclonal antibodies (mAbs) raised against human ␤ 2 GPI were selected on the basis of their crossreactivity with hamster ␤ 2 GPI. Two of these, one with LA activity, 5H2, and one with only anticardiolipin properties, 11E8, were infused at 0 to 10 mg/kg prior to photochemically induced vessel damage. 5H2 promoted thrombus formation dose dependently, raising the thrombus size from 6.0 arbitrary units (AU) in controls (n ‫؍‬ 9) to 65.0 AU in the high-dose group (10 mg/kg, n ‫؍‬ 6, P ‫؍‬ .007). The LA ؊ mAb 11E8 and mAb 27A8, reactive with human ␤ 2 GPI exclusively, did not significantly promote thrombus formation. In a second set of experiments, intact mAb 5H2 was compared to its fragments. Intact mAb 5H2 at 3.3 mg/kg and the equimolar dose of F(ab) 2 fragments (2.2 mg/kg) promoted thrombus formation equally well (55.8 AU, n ‫؍‬ 8 and 62.5 AU, n ‫؍‬ 7, respectively); mAb 5H2-derived Fab fragments were inactive. Immunohistochemical analysis showed platelet-rich thrombi, with 5H2 or its F(ab) 2 fragments mainly bound to individual platelets. Our results indicate that bivalent immune complex formation plays an important role in the genesis of arterial thrombosis by certain antiphospholipid antibodies. Cellular activation via the Fc portion of these immune complexes, however, is not essential, because F(ab) 2 fragments of 5H2 still promote thrombus formation. (Blood. 2003;

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Section: Introductionmentioning

confidence: 99%

Thrombogenicity of β2-glycoprotein I–dependent antiphospholipid antibodies in a photochemically induced thrombosis model in the hamster

Jankowski

Vreys

Wittevrongel

et al. 2003

Blood

166

126

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“…Arnout went on to replace cardiolipin with a commercial partial thromboplastin reagent or phosphatidylserine in the ELISA, hoping that this would more closely parallel the lupus anticoagulant activity. However, only moderate agreement was found between clotting tests and the various ELISAs, indicating that ELISA techniques cannot entirely replace coagulation tests for the detection of a lupus anticoagulant [23].…”

Section: Anticardiolipin Antibodiesmentioning

confidence: 99%

Attempts to make sense of the antiphospholipid syndrome

Vermylen

Carreras

Arnout

2007

Journal of Thrombosis and Haemostasis

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Many investigators have been intrigued by the paradoxical association of a circulating anticoagulant, first called lupus anticoagulant by Feinstein and Rapaport [1], with a tendency to develop thrombosis, as initially described by Walter Bowie [2]. Work in Leuven on this topic started when Luis Carreras, an Argentinian hematologist, joined the laboratory of blood coagulation at this university in 1979. At that time, the head of the laboratory was Marc Verstraete. Luis had a particular interest in antibody‐mediated coagulation disorders, and had prepared reviews on thrombosis and thrombocytopenia induced by heparin [3] and on the lupus inhibitor [4]. In Leuven, he joined Jos Vermylen, senior member of the laboratory, and an internist with particular interest in hemostasis, thrombosis and vascular disease. As such, Professor Vermylen was involved in both laboratory research and patient care.

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“…Anticardiolipin antibodies were determined using an enzyme immunosorbent assay (ELISA) as described (1) with minor modifications (20). Patient plasma samples were diluted 1:100 in phosphate buffered saline (PBS) containing 10% fetal calf serum unless stated otherwise; column fractions were diluted 1:20.…”

Section: Aizticardiolipiiz Antibodj Immunoassajmentioning

confidence: 99%

High-Dose Intravenous Immunoglobulin Treatment of a Pregnant Patient with an Antiphospholipid Syndrome: Immunological Changes Associated with a Successful Outcome

et al. 1994

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SummaryA patient with a history of habitual abortion, deep venous thrombosis, thrombocytopenia, high titer IgG anticardiolipin antibodies and a clearly positive lupus anticoagulant, was treated during her seventh pregnancy with high-dose intravenous immunoglobulins (IVIg) from the third month onwards. Every month, a daily infusion of 400 mg immunoglobulins per kg body weight was given during five consecutive days. The patient’s pregnancy ended preterm with a live birth, delivered by caesarian section because of a placental abruption. The 1070 g (P20-P25) weighing girl was in good health, apart from a bradycardia, due to dysfunction of the atrioventricular conduction.Each treatment with IVIg resulted in a slight reduction of both anticardiolipin antibodies and lupus anticoagulant levels and in an increase in platelet count. During the six-month observation period, a gradual decline in antiphospholipid antibodies and an increase in platelet count was found. The potential role of anti-idiotypic antibodies, present in the IVIg used for treatment, was studied. In vitro, IVIg were able to reduce the binding of the patient’s anticardiolipin antibodies to cardiolipin coated microtiter plates. The presence of anti-idiotypic antibodies in IVIg was further documented by affinity chromatography and by realtime biospecific interaction analysis (BIA) on a BIA-core instrument. Affinity purified anticardiolipin antibodies were retarded on a column of insolubilized IVIg and a weak interaction was found between IVIg and affinity purified patient antiphospholipid antibodies, coupled to the BIA-core biosensor. In addition, the same technology revealed increased levels of anti-antiphospholipid antibodies in the patient’s plasma following IVIg therapy. The partial and transient reduction of anti-phospholipid antibody levels observed immediately following each treatment course seems compatible with low affinity complexation of idiotype-antiidiotypes, resulting in an accelerated clearance of the autoantibodies. Despite the low affinity for the patient’s idiotypes, the beneficial long term effects observed could be related to an immune regulatory role of these anti-idiotypic antibodies on the synthesis of antiphospholipid antibodies.

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Detection of Lupus-Like Anticoagulants by an Enzyme-Linked Immunosorbent Assay Using a Partial Thromboplastin as Antigen; A Comparative Study

Cited by 9 publications

References 18 publications

Thrombogenicity of β2-glycoprotein I–dependent antiphospholipid antibodies in a photochemically induced thrombosis model in the hamster

Thrombogenicity of β2-glycoprotein I–dependent antiphospholipid antibodies in a photochemically induced thrombosis model in the hamster

Attempts to make sense of the antiphospholipid syndrome

High-Dose Intravenous Immunoglobulin Treatment of a Pregnant Patient with an Antiphospholipid Syndrome: Immunological Changes Associated with a Successful Outcome

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