scholarly journals Pathophysiology of the Antiphospholipid Antibody Syndrome

2021 ◽  
Author(s):  
David Green
Keyword(s):  
Antiphospholipid Syndrome ◽  
Binding Proteins ◽  
Membrane Receptors ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Clotting Factors ◽  
Anionic Phospholipid ◽  
Autoantibody Production ◽  
Phospholipid Binding ◽  
Glycoprotein I

The antiphospholipid syndrome is characterized by antibodies directed against phospholipid-binding proteins and phospholipids attached to cell membrane receptors, mitochondria, oxidized lipoproteins, and activated complement components. When antibodies bind to these complex antigens, cells are activated and the coagulation and complement cascades are triggered, culminating in thrombotic events and pregnancy morbidity that further define the syndrome. The phospholipid-binding proteins most often involved are annexins II and V, β2-glycoprotein I, prothrombin, and cardiolipin. A distinguishing feature of the antiphospholipid syndrome is the “lupus anticoagulant”. This is not a single entity but rather a family of antibodies directed against complex antigens consisting of β2-glycoprotein I and/or prothrombin bound to an anionic phospholipid. Although these antibodies prolong in vitro clotting times by competing with clotting factors for phospholipid binding sites, they are not associated with clinical bleeding. Rather, they are thrombogenic because they augment thrombin production in vivo by concentrating prothrombin on phospholipid surfaces. Other antiphospholipid antibodies decrease the clot-inhibitory properties of the endothelium and enhance platelet adherence and aggregation. Some are atherogenic because they increase lipid peroxidation by reducing paraoxonase activity, and others impair fetal nutrition by diminishing placental antithrombotic and fibrinolytic activity. This plethora of destructive autoantibodies is currently managed with immunomodulatory agents, but new approaches to treatment might include vaccines against specific autoantigens, blocking the antibodies generated by exposure to cytoplasmic DNA, and selective targeting of aberrant B-cells to reduce or eliminate autoantibody production.

Cutaneous manifestations of antiphospholipid syndrome

Lupus ◽  
2021 ◽  
pp. 096120332199010
Author(s):  
Minerva Gomez-Flores ◽  
Genesis Herrera-Argaez ◽  
Osvaldo Vazquez-Martinez ◽  
Maira Herz-Ruelas ◽  
Jorge Ocampo-Candiani ◽  
...  
Keyword(s):  
Antiphospholipid Syndrome ◽  
Binding Proteins ◽  
Cutaneous Manifestations ◽  
Phospholipid Binding

Antiphospholipid syndrome (APS) is an acquired thrombophilic disorder in which autoantibodies are produced against a variety of phospholipids and phospholipid-binding proteins. The purpose of this article is to review cutaneous findings in patients with APS diagnosis. An overview regarding prevalence, description, pathogenesis and histopathology, are described for cutaneous manifestations of APS.

scholarly journals The Wolf Hidden behind the Clots: Catastrophic Antiphospholipid Antibody Syndrome

2018 ◽  
Vol 2018 ◽  
pp. 1-4 ◽  
Author(s):  
Myat Han Soe ◽  
Krishna Adit Agarwal ◽  
Alueshima Akough-Weir
Keyword(s):  
Antiphospholipid Syndrome ◽  
Lupus Erythematosus ◽  
Anticoagulation Therapy ◽  
Multiple Organ ◽  
Clinical Syndrome ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Case Review ◽  
Cmv Infection ◽  
Thrombophilic Condition

Catastrophic antiphospholipid syndrome (CAPS) is a rare but highly fatal clinical syndrome that occurs in up to 1% of patients with antiphospholipid syndrome (APS). The diagnosis of CAPS is often delayed because its presentation with multiple organ thromboses can be confused with other thrombotic microangiopathies and severe sepsis. We report a case of CAPS in a patient with APS and systemic lupus erythematosus (SLE) presenting with thrombotic storm precipitated by trauma, cytomegalovirus (CMV) infection, and noncompliance with anticoagulation therapy. Our case reflects the “two-hit hypothesis” of APS in which the presence of antiphospholipid antibodies (first hit) increases the thrombophilic risk, and thromboses take place in the presence of another thrombophilic condition such as CMV infection in our case. In this case review, we discuss the diagnostic challenges and management of CAPS. In clinical practice, we aim to stress the importance of thorough evaluation and management of precipitating events such as infections in addition to timely diagnosis and treatment of this catastrophic clinical entity.

The antiphospholipid (antibody) syndrome

2011 ◽  
pp. 343-352
Author(s):  
Alan J. Hakim ◽  
Gavin P.R. Clunie ◽  
Inam Haq
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Autoimmune Diseases ◽  
Venous Thrombosis ◽  
Antiphospholipid Syndrome ◽  
Lupus Erythematosus ◽  
Lupus Anticoagulant ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Systemic Lupus ◽  
Pregnancy Morbidity

Introduction 344 Epidemiology and pathology 345 Clinical features of antiphospholipid syndrome 346 Treatment of antiphospholipid syndrome 348 Catastrophic antiphospholipid syndrome 350 The antiphospholipid syndrome (APS) was first described in the 1980s and comprises arterial and venous thrombosis with or without pregnancy morbidity in the presence of anticardiolipin (ACL) antibodies or the lupus anticoagulant (LAC). It can be primary, or secondary to other autoimmune diseases, most commonly systemic lupus erythematosus (SLE) (...

β2-Glycoprotein I: Target antigen for ‘antiphospholipid’ antibodies. Immunological and molecular aspects

Lupus ◽  
1998 ◽  
Vol 7 (2_suppl) ◽  
pp. 5-9 ◽  
Author(s):  
Y Sheng ◽  
DA Kandiah ◽  
SA Krilis
Keyword(s):  
Antiphospholipid Syndrome ◽  
Antiphospholipid Antibodies ◽  
Fluid Phase ◽  
Target Antigen ◽  
Phospholipid Membranes ◽  
Anionic Phospholipid ◽  
Glycoprotein I ◽  
High Concentrations ◽  
Molecular Aspects ◽  
Anionic Phospholipid Membranes

It has become clear that β2-glycoprotein I (β2GPI) is the most common and best-characterised antigenic target for ‘antiphospholipid’ (aPL) autoantibodies. These antibodies preferentially bind β2GPI that has been immobilised on anionic phospholipid membranes or certain synthetic surfaces. These surfaces appear to act by increasing antigen density to allow binding of intrinsically low-affinity anti-β2GPI autoantibodies. Binding of β2GPI in fluid phase is weak and requires high concentrations of β2GPI. Our understanding of the pathophysiology of the ‘Antiphospholipid’ Syndrome (APS) has increased exponentially with the number of studies into the interactions of aPL antibodies and β2GPI.

The Antiphospholipid Syndrome

Hematology ◽  
2007 ◽  
Vol 2007 (1) ◽  
pp. 136-142 ◽  
Author(s):  
Jacob H. Rand
Keyword(s):  
Antiphospholipid Syndrome ◽  
Pregnancy Complications ◽  
Binding Proteins ◽  
Clinical Manifestations ◽  
Therapeutic Approaches ◽  
Vascular Thrombosis ◽  
Phospholipid Binding ◽  
Thrombophilic Condition

Abstract The antiphospholipid syndrome (APS) is an autoimmune thrombophilic condition that is marked by the presence of antibodies that recognize phospholipid-binding proteins. The clinical manifestations of APS include vascular thrombosis and pregnancy complications, especially recurrent spontaneous miscarriages. This article provides an update on diagnostic and therapeutic approaches to this disorder.

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.

International Normalized Ratio (INR) Determined by Plasma-Based Methods Versus Point-of-Care Instruments in Patients with Antiphospholipid Antibody Syndrome.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1067-1067 ◽  
Author(s):  
Stephan Moll ◽  
Lauren McKnight ◽  
Allison Deal
Keyword(s):  
Point Of Care ◽  
Clinical Decision ◽  
Analysis Data ◽  
International Normalized Ratio ◽  
Antiphospholipid Antibody ◽  
Antiphospholipid Antibody Syndrome ◽  
Factor X ◽  
Research Support ◽  
Glycoprotein I ◽  
Factor Ii

Abstract Abstract 1067 Poster Board I-89 Background: In some patients with antiphospholipid antibody (APLA) syndrome treated with warfarin, the International Normalized Ratios (INRs) obtained from plasma, as well as from full blood via fingerstick by older point-of-care (POC) devices, are unreliable. Reliability of newer POC devices in APLA syndrome patients is unknown and was investigated in the present study. Methods: 60 patients on stable warfarin were enrolled: 30 with APLA syndrome, 30 without. INRs were determined using 4 POCs: CoaguChekXS®, ProTime®, the investigational ProTime®, and INRatio2®. Plasma from phlebotomy was tested for: PT, factor II activity, chromogenic factor X, anticardiolipin and anti-beta-2-glycoprotein I antibodies, lupus anticoagulant. Analysis: Data from the venipuncture INRs from the patients without APLA are used to estimate the relationship between INR and Factor II level and determine the therapeutic range of Factor II. Using the same therapeutic INR range, for each individual POC test the proportion of patients whose clinical decision based on the POC instrument is correct is estimated, along with 95% confidence intervals. This is done for patients with and without APLA. These two proportions are compared between the two groups using Fisher's Exact Tests; nominal p-values are reported. A similar analysis is done using the Factor X test as the gold standard. Results: Data collection has been completed; analysis of results is pending and will be available before December 2009. Conclusions: Data analysis will show whether the presently available POC devices give reliable INR results in patients with APLA syndrome on warfarin and can be reliably used to monitor warfarin therapy. Disclosures: Moll: Hemosense: research support; Roche: reserarch support; ITC: Consultancy, research support. McKnight:ITC: Honoraria. Deal:ITC: Consultancy.

Phagocytosis of platelet microvesicles and β2– glycoprotein I

2010 ◽  
Vol 104 (08) ◽  
pp. 335-341 ◽  
Author(s):  
Anhquyen Le ◽  
Anthony Prakasam ◽  
Hanan Abdel-Monem ◽  
Swapan Dasgupta ◽  
Perumal Thiagarajan
Keyword(s):  
Antiphospholipid Syndrome ◽  
Antiphospholipid Antibodies ◽  
Binding Capacity ◽  
Plasma Concentrations ◽  
Physiological Role ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Phospholipid Binding ◽  
Glycoprotein I

SummaryThe majority of the antiphospholipid antibodies, present in patients with antiphospholipid syndrome, are directed against conformational epitopes in β2-glycoprotein I. β2-glycoprotein I is an anionic phospholipid- binding 50-kDa plasma protein whose physiological role is not clear. Here we investigate the role of β2-glycoprotein I in the phagocytosis of phosphatidylserine-expressing platelet microvesicles and the effect of autoantibodies to β2-glycoprotein I on this process. We labelled the glycans of β2-glycoprotein I with BODIPY (4,4-difluoro- 4-bora-3a,4a-diaza-s-indacene)-hydrazide without affecting its phospholipid binding capacity. BODIPY-β2-glycoprotein I bound to platelet microvesicles in a concentration-dependent manner and promoted the phagocytosis of platelet microvesicles by THP-1 derived macrophages in vitro at physiological plasma concentrations with a half maximal effect at ∼10 μg/ml. β2-glycoprotein I-stimulated phagocytosis was inhibited by annexin A5 and the phosphatidylserine-binding C1C2 fragment of lactadherin. Furthermore, immunoaffinity purified β2-glycoprotein I-dependent antiphospholipid antibodies from five patients with antiphospholipid syndrome inhibited the phagocytosis in a concentration- dependent manner. These studies suggest that the binding of β2-glycoprotein I to phosphatidylserine-expressing procoagulant platelet microvesicles may promote their clearance by phagocytosis and autoantibodies to β2-glycoprotein I may inhibit this process to induce a procoagulant state.

Sign in / Sign up

Export Citation Format

Share Document