A Novel Flow Cytometric Annexin A5 Competition Assay for the Diagnosis of Antiphospholipid Syndrome.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4042-4042
Author(s):  
Lisa Senzel ◽  
Xiao-Xuan Wu ◽  
Jacob Rand
Keyword(s):  
Anticoagulant Activity ◽  
Anticardiolipin Antibody ◽  
Progressive Increase ◽  
Fluorescent Labeling ◽  
Annexin A5 ◽  
Antiphospholipid Antibody ◽  
Anionic Phospholipids ◽  
Flow Cytometric ◽  
Anticoagulant Function ◽  
A Minor

Abstract Annexin A5 (A5) is a potent anticoagulant protein that crystallizes over phospholipid surfaces, shielding them from availability for coagulation enzyme reactions. The antiphospholipid antibody (aPL) syndrome (APS) is an autoimmune thrombophilia that is marked by the presence of antibodies against phospholipid-binding proteins and the paradoxical lupus anticoagulant phenomenon. aPL antibodies can promote coagulation by interfering with the crystallization of A5, thereby increasing the exposure of blood to thrombogenic anionic phospholipids. Since a flow cytometric assay for aPL measuring A5 binding to frozen thawed platelets was previously reported, we investigated whether phosphatidylserine-bound polystyrene beads could provide a robust platform for the assay. Beads were incubated with sera from patients with the aPL syndrome and from non-aPL controls. Fluorescence-tagged A5 was added and samples were analyzed by flow cytometry. Similarly treated beads were also used in coagulation assays to determine whether A5 anticoagulant function was also inhibited. Control sera permitted fluorescent labeling of nearly all beads. In contrast, sera from aPL syndrome patients produced a major population of unlabeled beads, sometimes accompanied by a minor population of labeled beads. 7 of 13 confirmed aPL syndrome patients, and 7 of 12 anticardiolipin antibody positive patients, demonstrated reduced A5 binding in this assay, while 10 of 10 healthy blood donor controls did not. Dilution of the aPL sera resulted in progressive increase of A5 binding. Reduction of A5 binding appeared to correlate with reduced A5 anticoagulant activity (r=0.42, n=33, p=.01). This assay shows promise for investigating the effects of aPL antibodies on A5 binding and for the clinical diagnosis of the aPL syndrome. Figure Figure Figure Figure

Antiphospholipid Antibody Syndrome: The Flow Cytometric Annexin A5 Competition Assay as a Diagnostic Tool.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3981-3981
Author(s):  
Aaron Tomer ◽  
Shira Bar-Lev ◽  
Stela Fleisher ◽  
Boris Shenkman ◽  
Michael Friger ◽  
...  
Keyword(s):  
Lupus Erythematosus ◽  
Vascular Complications ◽  
Relative Sensitivity ◽  
Annexin A5 ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Flow Cytometric Assay ◽  
Anionic Phospholipid ◽  
Anionic Phospholipids ◽  
Flow Cytometric

Abstract The mechanism underlying hypercoagulability in antiphospholipid antibody syndrome (APS) is uncertain. Here, we present a flow-cytometric assay (FCA) based on the hypothesis that anti-platelet-anionic-phospholipid autoantibodies (aPL) interfere with the activity of the natural anticoagulant protein annexin A5, thereby accelerating platelet procoagulant activity. This study assessed the clinical utility of the feasible FCA, which demonstrates the competition of the patient’s aPL with the binding of annexin A5 to the platelet-anionic-phospholipids, in the diagnosis of APS. Sixty-two (94%) of 66 APS patients, 20 (51%) of 39 patients with systemic lupus erythematosus and two (4%) of 49 healthy individuals were positive by FCA. Compared with the anticardiolipin (aCL) assay, the relative sensitivity was 82% and the specificity 73∴3%. However, 19 (25%) aCL-negative patients were positive by FCA; 12 were positive for lupus-anticoagulant (LA). Compared with LA assay, the relative sensitivity was 85% and the specificity 72∴2%. However, 21 (26%) LA-negative patients were FCA-positive, 12 were positive for aCL. The FCA was particularly sensitive for APS patients with arterial (97∴0%) and gestational vascular complications (100%) with overall sensitivity of 95% and specificity of 97%. Our findings suggest that the FCA is practical, sensitive and specific for the detection of clinically relevant aPL in the diagnosis of APS.

Antiphospholipid Antibody Syndrome: Annexin V Competitive Flow Cytometric Assay for Determination of Anti-Platelet Phospholipid Autoantibodies.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4126-4126
Author(s):  
Aaron Tomer ◽  
Shira Barlev ◽  
Mahmoud Abu-Shakra ◽  
Boris Shenkman
Keyword(s):  
Lupus Erythematosus ◽  
Annexin V ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Flow Cytometric Assay ◽  
Platelet Phospholipid ◽  
Standard Equipment ◽  
Anionic Phospholipids ◽  
Flow Cytometric

Abstract A flow cytometric assay was developed for the determination of autoantibodies directed against platelet anionic-phospholipids in antiphospholipid syndrome (APS). The method is based on demonstrable competition between the placental anticoagulant protein I, annexin V, and the patients’ autoantibodies on the platelet anionic-phospholipids (the binding site for the prothrombinase complex; prothrombin, factors Va and Xa). The method is practical and rapid, uses readily available reagents, and standard equipment. Ninety-two plasma samples, 41 from patients with clinical diagnosis of APS, 27 from patients with systemic lupus erythematosus (SLE) and 24 from healthy individuals were analyzed. Thirty-five (85%) of patients with APS (either with or without SLE), 15 (94%) of patients with APS and SLE, and 20 (80%) of APS patients without SLE were positive. Nineteen (70%) out of 27 patients with SLE alone were also positive; of whom 15 (58%) were positive for either anti-cardiolipin antibody (ACL) or lupus anti-coagulant (LAC). Comparison with ACL showed 40 (93%) out of 43 patients positive for ACL were also positive by flow cytometry (FCM). However, 13 (48%) out of 27 patients negative for ACL were found positive by FCM. Seven of these patients have primary APS and 6 have SLE; 7 of whom were positive for LAC. Three (13%) out of the 24 control samples, all negative by FCM, were positive for ACL. Comparison with LAC showed 32 (91%) out of 35 patients positive for LAC also positive by FCM. Of 18 patients negative for LAC, 7 (39%) were negative and 11 (61%) were positive by FCM. Four of the 11 patients have a diagnosis of APS and 7 of SLE; 6 of whom were positive for ACL. None of the controls, all negative by FCM, was positive for LAC. In conclusion, the annexin V competitive flow cytometric assay for the determination of anti-platelet phospholipid autoantibodies maybe useful for the laboratory diagnosis of APS.

Correlation between antiphospholipid antibodies that recognize domain I of β2-glycoprotein I and a reduction in the anticoagulant activity of annexin A5

Blood ◽  
2006 ◽  
Vol 109 (4) ◽  
pp. 1490-1494 ◽  
Author(s):  
Bas de Laat ◽  
Xiao-Xuan Wu ◽  
Menno van Lummel ◽  
Ronald H. W. M. Derksen ◽  
Philip G. de Groot ◽  
...  
Keyword(s):  
Antiphospholipid Antibodies ◽  
Lupus Anticoagulant ◽  
Anticoagulant Activity ◽  
Annexin A5 ◽  
Anionic Phospholipids ◽  
Glycoprotein I ◽  
Group A ◽  
Group B ◽  
Domain I ◽  
American Authors

Abstract The paradoxical correlation between thrombosis and the lupus anticoagulant (LAC) effect is an enigmatic feature of the antiphospholipid (aPL) syndrome. The Dutch authors previously reported that thrombosis-related anti–β2-glycoprotein I (β2GPI) antibodies recognize domain I and cause LAC. The American authors reported that aPLs disrupt an anticoagulant annexin A5 (AnxA5) crystal shield. We investigated whether antidomain I antibodies correlate with disruption of AnxA5-anticoagulant activity. We studied a well-characterized group of 33 patients including subgroups with β2GPI-dependent LAC that recognize domain I (n = 11), with β2GPI-independent LAC (n = 12), and lacking LAC (n = 10). The effects on AnxA5-anticoagulant activity were determined with an AnxA5 resistance assay that measures coagulation times with and without AnxA5. Patients with β2GPI-dependent LAC (group A, all with thrombosis) had significantly lower AnxA5-anticoagulant ratios than those with β2GPI-independent LAC (group B, thrombosis n = 4; 157.8% versus 235.6%, P < .001) and those without LAC (group C, thrombosis n = 2; 157.8% versus 232.5%, P < .001). There was no difference in the ratios between groups B and C (P = .92). Plasmas with β2GPI-dependent LAC that recognize domain I displayed significantly increased AnxA5 resistance, suggesting that specifically anti-β2GPI antibodies compete with AnxA5 for anionic phospholipids. These results are consistent with a model in which aPL antibodies may promote thrombosis by interfering with the anticoagulant activity of AnxA5.

Pathogenic antiphospholipid antibody: an antigen-selected needle in a haystack

Blood ◽  
2004 ◽  
Vol 104 (6) ◽  
pp. 1711-1715 ◽  
Author(s):  
Patricia Lieby ◽  
Vincent Poindron ◽  
Stamatiki Roussi ◽  
Cyril Klein ◽  
Anne-Marie Knapp ◽  
...  
Keyword(s):  
Antiphospholipid Antibodies ◽  
Germ Line ◽  
Annexin A5 ◽  
Antiphospholipid Antibody ◽  
Variable Regions ◽  
Anionic Phospholipids ◽  
Pregnant Mice

Abstract Antiphospholipid antibodies represent a heterogeneous group of autoantibodies directed against anionic phospholipids (PLs) usually linked to protein cofactors. Their presence during the antiphospholipid syndrome is associated with risks of thrombosis and fetal losses. Among 5 randomly selected monoclonal antiphospholipid antibodies, all originating from a single patient suffering from this autoimmune disease, only 1 induced fetal losses when passively injected into pregnant mice. Its antiphospholipid activity was dependent on annexin A5, and its variable regions contained mainly 3 replacement mutations. To clarify the role of these mutations in the pathogenicity of the antibody, they were in vitro reverted to the germ line configuration. The resulting “germ line” antibody reacted with multiple self-antigens and only partially lost its reactivity against PLs, but it was no more dependent on annexin A5 and, more importantly, was no more pathogenic. This study illustrates that the in vivo antigen-driven maturation process of natural autoreactive B cells can be responsible for pathogenicity. (Blood. 2004;104:1711-1715)

Antiphospholipid antibody-mediated interference with annexin-V anticoagulant activity

2001 ◽  
Vol 21 (02) ◽  
pp. 50-53 ◽  
Author(s):  
X.-X. Wu ◽  
J. H. Rand
Keyword(s):  
Antiphospholipid Syndrome ◽  
Protein Complexes ◽  
Anticoagulant Activity ◽  
Annexin V ◽  
Phospholipid Bilayer ◽  
Antiphospholipid Antibody ◽  
Anionic Phospholipid ◽  
Anionic Phospholipids ◽  
Coagulation Proteins ◽  
Recurrent Pregnancy Losses

SummaryThe antiphospholipid (aPL) syndrome is a disorder in which vascular thrombosis and/or recurrent pregnancy losses occur together with serologic and coagulation evidence for antibodies directed against anionic phospholipid-protein complexes. Evidence has been developed for the idea that thrombosis in this syndrome may result from disruption of the binding of annexin-V to the phospholipids which line the placental and systemic vasculatures. We hypothesize that annexin-V, a protein known to have high affinity for anionic phospholipids, plays a thromboregulatory role at the vascular-blood interface by shielding anionic phospholipids from complexation with coagulation proteins in circulating blood. We propose that the thrombotic manifestations of the antiphospholipid syndrome are due to disruption of this annexin-V shield by antiphospholipid antibodies, thereby resulting in a net increase of thrombogenic phospholipids exposed to circulating blood. The accumulated data from tissue immunohistochemistry, trophoblast and endothelial cell culture studies, coagulation studies using noncellular phospholipids, and competition studies on artificial phospholipid bilayer are consistent with the hypothesis that the interference with the binding of annexin-V to anionic phospholipid surfaces plays an important role in the mechanism of thrombosis and in pregnancy loss in the antiphospholipid syndrome.

Apolipoprotein H (apoH)-dependent autoantibodies and apoH protein polymorphism in selected patients showing lupus anticoagulant activity

2005 ◽  
Vol 43 (1) ◽  
Author(s):  
Željka Vogrinc ◽  
Milica Trbojević-Čepe ◽  
Désirée Coen ◽  
Ksenija Vitale ◽  
Ana Stavljenić-Rukavina
Keyword(s):  
Antiphospholipid Antibodies ◽  
Lupus Anticoagulant ◽  
Anticoagulant Activity ◽  
Protein Polymorphism ◽  
Antiphospholipid Antibody ◽  
Anionic Phospholipids ◽  
Epitope Specificity ◽  
Apolipoprotein H ◽  
Antibody Epitope

AbstractApolipoprotein H (apoH) is considered to be a necessary cofactor for the binding of certain antiphospholipid antibodies to anionic phospholipids. Some apoH-dependent antiphospholipid antibodies also exert lupus anticoagulant (LA) activity, which seems to depend on antiphospholipid antibody epitope specificity. The aim of this study was to evaluate whether the presence of less frequent

A GENERAL MECHANISM FOR LUPUS ANTICOAGULANTS

1987 ◽  
Author(s):  
V Pengo ◽  
M J Heine ◽  
P Thiagarajan ◽  
s s Shapiro
Keyword(s):  
Lupus Anticoagulant ◽  
Anticoagulant Activity ◽  
Protein A ◽  
Coagulation Factors ◽  
Phosphatidyl Serine ◽  
General Mechanism ◽  
Factor X ◽  
Lupus Anticoagulants ◽  
Calcium Dependent ◽  
Anionic Phospholipids

Although- a number of observations have implied that lupus anticoagulants have immunologic specificity towards anionic. phospholipids, thereby prolonging phospholipid-dependent coagulation tests, this assumption has been directly demonstrated in only one patient with a monoclonal IgM paraprotein. We have tested the generality of this hypothesis directly by isolating five IgG lupus anticoagulants from patients with lupus-like syndromes and/or thrombosis. IgG lupus anticoagulant fractions were isolated free of other plasma proteins and free of contaminating phospholipid by adsorption to and elution from cardiolipin-cholesterol-dicetylphosphate liposomes , followed by chromatography on protein A-Sepharose. Cardiolipin liposomes, but not phosphatidylcholine liposomes, were capable of removing all, or nearly all, lupus anticoagulant activity from patient plasma. Anticardiolipin and lupus anticoagulant activity were both present in acidic fractions on isoelectric focusing. F(ab’)2 fragments retained lupus anti coagulant activity and bound to cardiolipin in an ELISA assay. The affinity-purified IgG preparations reacted with cardiolipin, phosphatidyl serine , phosphatidylinositol and phosphatidic acid, but not with phosphatidylcholine or phosphatidyl ethanol amine, and inhibited calcium-dependent binding of prothrombin and of factor X to phosphatidy1serine-coated surfaces. These data demonstrate a general mechanism for the action of lupus anticoagulants: antibodies that have immunologic specificity towards anionic phospholipids, thereby blocking the calcium-mediated binding of vitamin K-dependent coagulation factors to coagulation-active phospholipid surfaces.

scholarly journals Protein C deficiency resulting from possible double heterozygosity and its response to danazol

Blood ◽  
1988 ◽  
Vol 71 (2) ◽  
pp. 370-374
Author(s):  
RA Gruppo ◽  
P Leimer ◽  
RB Francis ◽  
RA Marlar ◽  
E Silberstein
Keyword(s):  
Functional Activity ◽  
Protein C ◽  
Anticoagulant Activity ◽  
Anticoagulation Therapy ◽  
Renal Vein Thrombosis ◽  
Type I ◽  
Amidolytic Activity ◽  
Protein C Deficiency ◽  
Protein Levels ◽  
Anticoagulant Function

A unique family with protein C (PC) deficiency is described. The proband had a history of renal vein thrombosis as a newborn and iliofemoral thrombosis at the age of 6 years. After 6 months of heparin treatment, discontinuation of anticoagulation therapy was accompanied by persistent hypofibrinogenemia with increased fibrinogen consumption. With continuous infusion of heparin, fibrinogen turnover normalized, and the child has remained free of thrombosis. Both the immunologic level of PC and the functional activity measured by amidolytic assay were moderately reduced (47% and 34%, respectively). Functional activity of PC measured by its anticoagulant activity was disproportionately lower (14%). A 3-year-old asymptomatic sibling had a similar disproportionate reduction of PC anticoagulant activity compared with the amidolytic activity or immunologic level. The mother demonstrated type I PC deficiency with a proportionate reduction in immunologic protein levels (59%), anticoagulant activity (52%), and amidolytic activity (46%), whereas the father had type II PC deficiency with normal immunologic protein levels (102%), normal amidolytic function (98%), but a low anticoagulant function (50%). An abnormal PC molecule was detected by two-dimensional immunoelectrophoresis in the father and two children. These data are consistent with the hypothesis that the children are doubly heterozygous for two different types of PC deficiency inherited from each of the parents. A 14-day trial of danazol in the proband resulted in a rise in the PC antigen concentration from 66% to 98% but no change in PC anticoagulant function.

Pyoderma Gangrenosum Mimicking Antiphospholipid Antibody Syndrome in a Child With Juvenile Systemic Lupus Erythematosus

2020 ◽  
Author(s):  
metin kaya gürgöze ◽  
Aslıhan Kara ◽  
Mehmet yusuf sarı ◽  
İlknur Çalık ◽  
Saadet Akarsu
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Skin Biopsy ◽  
Pyoderma Gangrenosum ◽  
Lupus Erythematosus ◽  
Anticoagulation Therapy ◽  
Anticardiolipin Antibody ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Systemic Lupus ◽  
History Of

Abstract Background: Although pyoderma gangrenosum (PG) -like lesions have been rarely described in adults with the antiphospholipid antibody syndrome (APS) and systemic lupus erythematosus (SLE), the occurrence of PG as a preceding manifestation of APS in children with SLE has not been reported until. We present a young girl with SLE and APS who developed progressive extstensive ulcerations that were consistent with PG.Case presentation: A 14-year-old girl with a 2-year history of SLE was admitted to our department, complaining painful crusted ulcerations on her legs. Skin biopsy was reported as PG. However, she did not respond to immunosuppressive therapy administered. When her skin biopsy findings is reassessed in keeping with the positive anticardiolipin antibody results, superficial small vessel microthrombosis was observed. Diagnosis of APS and PG developing secondary to SLE were made. It was resulted in marked clinical improvement with anticoagulation therapy in addition to immunosuppressives as is recommended in APS. Conclusions: Based in clinical, pathological and response to proposed treatment, we can state that PG -like lesions in children with SLE could be considered as a secondary form of APS.

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