Increased Prevalence of Anti-CD36 and Elevated Endothelial Microparticles in Patients with Recurrent Thrombosis.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1632-1632
Author(s):  
Carlos J. Bidot ◽  
Wenche Jy ◽  
Camile Ortega ◽  
Larry L. Horstman ◽  
Carlos Bidot ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Platelet Activation ◽  
Lupus Anticoagulant ◽  
Clinical Laboratory ◽  
Test Methods ◽  
Recurrent Thrombosis ◽  
Antiplatelet Antibody ◽  
Transmembrane Glycoprotein ◽  
Glycoprotein I ◽  
Anti Phospholipid Syndrome

Abstract BACKGROUND: CD36 is a widely distributed transmembrane glycoprotein, called GpIV on platelets, involved in various physiologic processes. It has been implicated in thrombogenic pathologies such as diabetes, atherosclerosis and anti-phospholipid syndrome (APS). It is also an adhesion molecule capable of interacting with collagens and is considered a platelet collagen receptor. We investigated autoantibodies (Ab) against CD36 in TTP [Schultz et al, BrJH 103:849, 1998]. The present study was undertaken to explore relationships of anti-platelet Ab (aPlt-Ab), antiphospholipid Ab (APLA), and circulating cell-derived microparticles (MP) in patients with thrombosis. METHODS: Forty-five patients with documented thrombosis (TB) referred for hypercoagulable workups were recruited consecutively. Of them, 18 suffered from recurrent thrombosis (rTB) while 27 had a single event (sTB) within the past 5 years. We measured APLA, lupus anticoagulant (LA), antiplatelet antibody (aPlt-Ab) and MP. The APLA were IgG and IgM against cardiolipin (CL) and β2-glycoprotein-I (β2GP1) measured by ELISA. The aPlt-Abs were IgG and IgM reacting to GpIIb/IIIa (CD41b), GpIb/IX (CD42b), and GpIV (CD36), assayed by the PAICA method of Macchi et al [Thromb Haemost 76:1020, 1996]. The following types of MP were measured by flow cytometry: endothelial MP defined by CD31+/CD42− (EMP31) or by CD62E+ (EMP62); platelet MP defined by CD31+/CD42+ (PMP); leukocyte MP defined by CD45+ (LMP); and red blood cell MP by glycophorin+ (RMP). Lupus anticoagulant (LA) was measured in the hospital clinical laboratory and was considered positive if 2 of 3 different test methods were positive. Platelet activation was measured by CD62p expression in flow cytometry. RESULTS: Although both groups had increased prevalence of APLA and LA, there were no significant differences between the sTB and rTB groups. About 70% of patients in both groups were positive for at least one APLA. Of the aPlt-Ab, only aGpIV (aCD36) statistically discriminated between the groups, being more frequent in rTB for both IgG (p<0.02) and IgM (p<0.02). Among the MPs assayed, PMP were elevated in all patients in both groups. EMP62 discriminated best between rTB and sTB (p=0.003). LMP and RMP were also significantly higher in rTB than sTB, p<0.025. When we compared patients CD36+ vs CD36− we found that EMP62 was more frequently elevated in CD36+ patients (7/12, 58%) than in CD36− patients (2/32, 6%), p=0.001. Platelet activation marker CD62p was more often increased in rTB than sTB, p=0.022. CONCLUSION: GpIV (CD36) antibodies are the most prominent risk factor for rTB to emerge from this study. This confirms a previous report [Pelegri et al, Clin Exp Rheum 21:221, 2003]. EMP, LMP, RMP and platelet activation (CD62p) are also increased in the recurrent TB group vs single TB. EMP62 were associated with aCD36. Since CD36 is found also on endothelial cells, this suggests that aCD36 could be responsible for the high EMP62 in the rTB group. The present study demonstrates an association between high EMP62 and aCD36. We suggest that persisting autoantibodies against GpIV activate EC to predispose to recurrent thrombosis.

scholarly journals Diagnostic Challenges on the Laboratory Detection of Lupus Anticoagulant

Biomedicines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 844
Author(s):  
Armando Tripodi
Keyword(s):  
Lupus Anticoagulant ◽  
Clinical Laboratory ◽  
External Quality Assessment ◽  
State Of The Art ◽  
Diagnostic Procedures ◽  
External Quality ◽  
Glycoprotein I ◽  
Current State ◽  
Clinical Laboratories

Lupus anticoagulant (LA) is one of the three laboratory parameters (the others being antibodies to either cardiolipin or β2-glycoprotein I) which defines the rare but potentially devastating condition known as antiphospholipid syndrome (APS). Testing for LA is a challenging task for the clinical laboratory because specific tests for its detection are not available. However, proper LA detection is paramount for patients’ management, as its persistent positivity in the presence of (previous or current) thrombotic events, candidate for long term anticoagulation. Guidelines for LA detection have been established and updated over the last two decades. Implementation of these guidelines across laboratories and participation to external quality assessment schemes are required to help standardize the diagnostic procedures and help clinicians for appropriate management of APS. This article aims to review the current state of the art and the challenges that clinical laboratories incur in the detection of LA.

Antigenic Specificities of Antiphospholipid Autoantibodies: Implications for Clinical Laboratory Testing and Diagnosis of the Antiphospholipid Syndrome

Lupus ◽  
1996 ◽  
Vol 5 (5) ◽  
pp. 425-430 ◽  
Author(s):  
RAS Roubey
Keyword(s):  
Clinical Studies ◽  
Lupus Anticoagulant ◽  
Laboratory Testing ◽  
Clinical Laboratory ◽  
Clinical Manifestations ◽  
Anticardiolipin Antibodies ◽  
Protein Antigens ◽  
Advantages And Disadvantages ◽  
Glycoprotein I ◽  
Clinical Laboratory Testing

Most autoantibodies associated with the antiphospholipid (aPL) syndrome and detected in standard anticardiolipin and/or lupus anticoagulant assays are directed against β2-glycoprotein I (β2-GPI) or prothrombin. Recent data indicate that these antibodies can also be detected in immunoassays utilizing purified protein antigens, in the absence of phospholipids. Initial clinical studies suggest that positivity in anti-β2-GPI immunoassays is more closely associated with the clinical manifestations of the aPL syndrome than is positivity in conventional anticardiolipin ELISAs. Anti-β2-GPI immunoassays may detect certain anti-β2-GPI antibodies that are not detectable in conventional anticardiolipin assays, but do not detect authentic (β2-GPI-independent) anticardiolipin antibodies. It appears that the former, but not the latter, antibodies are associated with the clinical manifestations of the aPL syndrome. The potential advantages and disadvantages of these new immunoassays in the clinical evaluation of the aPL syndrome are discussed.

scholarly journals Anti-Phosphatidylserine/Prothrombin Antibodies at Two Points: Correlation With Lupus Anticoagulant and Thrombotic Risk

2021 ◽  
Vol 12 ◽  
Author(s):  
Natalia Egri ◽  
Chelsea Bentow ◽  
Laura Rubio ◽  
Gary L. Norman ◽  
Susana López-Sañudo ◽  
...  
Keyword(s):  
Lupus Anticoagulant ◽  
Clinical Manifestations ◽  
Classification Criteria ◽  
Risk Markers ◽  
Thrombotic Risk ◽  
Pregnancy Morbidity ◽  
Glycoprotein I ◽  
Pt Complex ◽  
Associated Proteins ◽  
Anti Phospholipid Syndrome

Antibodies to phospholipids (aPL) and associated proteins are a hallmark in the diagnosis of anti-phospholipid syndrome (APS). Those included in the classification criteria are the lupus anticoagulant (LA) and the IgG and IgM isotypes of anticardiolipin (aCL) and anti-beta-2 glycoprotein I (β2GPI) antibodies. Non-classification criteria markers such as autoantibodies that recognize the phosphatidylserine/prothrombin (aPS/PT) complex have been proposed as biomarkers for APS. Studies of aPS/PT antibodies have shown a strong correlation to clinical manifestations and LA. We aimed to study the value and the persistence of aPS/PT IgG and IgM antibodies in a cohort of consecutive patients with clinical suspicion of APS and their utility as thrombotic risk markers. Our study, with 103 patients, demonstrates that persistently positive results for aPS/PT IgG antibodies were significantly associated with APS classification, thrombosis, triple aPL positivity, LA positive result, and the Global APS Score (GAPSS) > than 9 points (p < 0.01, for each condition). On the other hand, no association was seen with pregnancy morbidity (p = 0.56) and SLE (p = 0.07). Persistence of aPS/PT antibodies, defined according to the current laboratory classification criteria, likely improves the diagnosis and clinical assessment of patients with APS.

Scientific and Standardization Committee Communications Comparison of Test Methods for the Lupus Anticoagulant: International Survey on Lupus Anticoagulants-I (ISLA-1)

1990 ◽  
Vol 64 (03) ◽  
pp. 478-484 ◽  
Author(s):  
Thomas Exner ◽  
Douglas A Triplett ◽  
David A Taberner ◽  
Margaret A Howard ◽  
E Nigel Harris
Keyword(s):  
Lupus Anticoagulant ◽  
Test Methods ◽  
Positive Sample ◽  
Direct Proportion ◽  
Clotting Time ◽  
Preliminary Screening ◽  
Activated Platelets ◽  
Tissue Thromboplastin ◽  
Kaolin Clotting Time ◽  
Induced Defects

SummarySix lyophilized plasma samples were sent to 20 “expert” laboratories for assessment of lupus anticoagulant (LA). Four samples contained pooled LA of graded potency mixed with aged normal plasma. One contained LA plus cephalin phospholipid and one contained a nonspecific venom anticoagulant. Sixteen methods were used overall with some participants using up to 8 methods. Results were scored in regard to the known potencies of LA in the samples and other known induced defects.Activated partial thromboplastin time (APTT) tests used by most participants for preliminary screening were relatively sensitive, but non-specific. Platelet or phospholipid neutralization procedures (PNP) appeared to be sensitive and specific but showed a non-linear response to increased LA content. Kaolin clotting time (KCT) tests showed the most sensitive response to increased LA content but the weaker LA were not scored as abnormal by most laboratories as the samples may have contained platelet fragments. Other commonly used tests such as the tissue thromboplastin inhibition (TTI) test and the dilute Russell’s viper venom test (DRVVT) were carried out somewhat inconsistently. The variability in performance of tests in different laboratories indicates that standardization of methodology is urgently required.Generally it seemed that most clotting tests were “bypassed” by the addition of phospholipid to a known LA-positive sample in apparently direct proportion to their sensitivity. Sample preparation, especially prevention of contamination with activated platelets is a vital preliminary part in the assay of LA.

A P-Selectin/CD62P Monoclonal Antibody (LYP-20), in Tandem with Flow Cytometry, Detects in vivo Activated Circulating Rat Platelets in Severe Vascular Trauma

1994 ◽  
Vol 72 (05) ◽  
pp. 745-749 ◽  
Author(s):  
Elza Chignier ◽  
Maud Parise ◽  
Lilian McGregor ◽  
Caroline Delabre ◽  
Sylvie Faucompret ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Flow Cytometry ◽  
Platelet Activation ◽  
Peripheral Blood ◽  
Vascular Trauma ◽  
Activated Platelets ◽  
Group I ◽  
Group Ii ◽  
Rat Platelets

SummaryP-selectin, also known as CD62P, GMP140 or PADGEM, is present in platelet a-granules and endothelial cell Weibel-Palade bodies and is very rapidly expressed on the surface of these cells on activation. In this study, an anti P-selectin monoclonal antibody (LYP20) was used, in tandem with flow cytometry, to identify activated platelets at the site of induced vascular trauma or in peripheral blood. Moreover, electron microscopy was performed to characterize sites of vascular trauma and quantify the number of adhering platelets. The same induced vascular trauma was observed to result into animals responding in 2 different ways (Group I, Group II) following the degree of platelet activation. Five rats, out of 14 with induced vascular trauma, had more than half of their circulating platelets expressing P-selectin when drawn at the site of the trauma (67.4% ± 3.44) or in peripheral blood (78.5% ± 2.5) (Group I). In the remaining 9 animals a much smaller proportion of circulating platelets expressed P-selectin when assayed from trauma sites (18% ± 3.34) or in peripheral blood (18.0% ± 4.30) (Group II). Enhanced P-selectin expression by circulating platelets in Group I, compared to Group II, appears to be linked to the degree of activated platelets adhering at sites of trauma (171 ± 15 × 103 platelets versus 48 ± 31 × 103 platelets per mm2). In the 5 control animals, that were not operated on, platelets expressing P-selectin when drawn at the site of a mock trauma (7.0% ± 1.84) or in the peripheral blood (11.2% ± 3.30) showed little activation. In addition, no platelet adhesion was seen on the vascular bed of these animals. Results from this study show that analysis of P-selectin (CD62P) expression, in circulating platelets, is a valuable and rapid marker of platelet activation following severe vascular trauma induced in rats. However, activated platelets were not detected to the same extent in the peripheral blood of all animals having undergone vascular trauma. It is conceivable that platelets, depending on the degree of activation, may be actively sequestered in organs and prevented from circulating. Alternatively, P-selectin may be rapidly endocytosed, or not expressed, by activated circulating platelets depending on the type of agonists implicated in vivo activation.

Increased Levels of β2-Glycoprotein I (aca-Cofactor) in Patients with Lupus Anticoagulant

1992 ◽  
Vol 67 (03) ◽  
pp. 386-386 ◽  
Author(s):  
M Galli ◽  
S Cortelazzo ◽  
M Daldossi ◽  
T Barbui
Keyword(s):  
Lupus Anticoagulant ◽  
Glycoprotein I

Synchronized Inhibition of the Phospholipid Mediated Autoactivation of Factor XII in Plasma by β2-glycoprotein I and Anti-β2-glycoprotein I

1995 ◽  
Vol 73 (05) ◽  
pp. 798-804 ◽  
Author(s):  
Inger Schousboe ◽  
Margit Søe Rasmussen
Keyword(s):  
Lupus Erythematosus ◽  
Lupus Anticoagulant ◽  
Response Curve ◽  
Inhibitory Effect ◽  
Factor Xii ◽  
High Antibody ◽  
Contact Activation ◽  
Maximal Inhibition ◽  
Lupus Anticoagulants ◽  
Glycoprotein I

SummaryLupus anticoagulants are a group of antibodies commonly found in patients with autoimmune diseases such as systemic lupus erythematosus. Lupus anticoagulants inhibit phospholipid dependent coagulation and may bind to negatively charged phospholipids. Recent studies have suggested an association between anti-β2-glycoprotein I and a lupus anticoagulant, whose activity is frequently dependent on the presence of β2-glycoprotein I. Based on these observations, the effect of anti-β2-glycoprotein I on the autoactivation of factor XII in plasma was investigated. Autoactivation initiated by the presence of negatively charged phospholipids, but not by sulfatide, was strongly inhibited by immunoaffinity purified anti-β2-glycoprotein I. The dose-response curve of anti-β2-gly coprotein I was identical with that of a precipitating antibody, showing no inhibition at low and high antibody dilutions and maximal inhibition at an intermediate dilution. At high antibody concentrations, an increased rate of factor Xlla activation was observed. This increase was of the same magnitude as the decreased rate observed in plasma supplemented with the same amount of β2-glycoprotein I as in the plasma itself. This confirms the inhibitory effect of β2-GP-I on the contact activation and shows that inhibition is effective on the autoactivation of factor XII in plasma. The inhibitory action of β2-glycoprotein I was independent of the inhibition caused by the anti- β2-glycoprotein I/β2-glycoprotein I complex suggesting a synchronized inhibition of factor XII autoactivation by β2-glycoprotein I and anti-β2-gly coprotein I. The inhibition caused by the antibody is suggested to be caused by a reduced availability of negatively charged phospholipids due to the binding of the anti-β2- GP-I/β2-GP-I complex. This complex may be a lupus anticoagulant.

A Simple and Rapid Method to Determine GPIIb/IIIa-Receptor Inhibitor Activity in Whole Blood

1999 ◽  
Vol 19 (03) ◽  
pp. 134-138
Author(s):  
Gitta Kühnel ◽  
A. C. Matzdorff
Keyword(s):  
Flow Cytometry ◽  
Platelet Count ◽  
Blood Sample ◽  
Platelet Activation ◽  
Whole Blood ◽  
Receptor Occupancy ◽  
Aggregate Formation ◽  
Inhibitor Activity ◽  
Receptor Inhibitor

SummaryWe studied the effect of GPIIb/IIIa-inhibitors on platelet activation with flow cytometry in vitro. Citrated whole blood was incubated with increasing concentrations of three different GPIIb/IIIa-inhibitors (c7E3, DMP728, XJ757), then thrombin or ADP were added and after 1 min the sample was fixed. Samples without c7E3 but with 0.1 U/ml thrombin had a decrease in platelet count. Samples with increasing concentrations of c7E3 had a lesser or no decrease in platelet count. The two other inhibitors (DMP 725, XJ757) gave similar results. GPIIb/IIIa-inhibitors prevent aggregate formation and more single platelets remain in the blood sample. The agonist-induced decrease in platelet count correlates closely with the concentration of the GPIIb/IIIa inhibitor and receptor occupancy. This correlation may be used as a simple measure for inhibitor activity in whole blood.

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