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.

Pathological Anti-β2-Glycoprotein I Antibodies Disrupt the Anticoagulant Activity of Annexin A5: A Possible Explanation for the Lupus Anticoagulant Paradox.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 135-135
Author(s):  
Bas de Laat ◽  
Xiao-Xuan Wu ◽  
Menno van Lummel ◽  
Ronald H.W.M. Derksen ◽  
Philip G. de Groot ◽  
...  
Keyword(s):  
Lupus Anticoagulant ◽  
Anticoagulant Activity ◽  
Annexin A5 ◽  
Double Blind Study ◽  
Clotting Time ◽  
Double Blind ◽  
Glycoprotein I ◽  
Group A ◽  
Group B

Abstract One of the most enigmatic features of the antiphospholipid (aPL) syndrome is the paradoxical correlation between thrombosis and the in vitro lupus anticoagulant (LAC) effect. It has recently been shown that only LAC that are due to β2-glycoprotein I (β2GPI) antibodies correlate with thrombosis. It has also been reported that aPL antibodies can disrupt the formation of an anticoagulant crystal shield that is formed by annexin A5 (AnxA5) over phospholipids bilayers. This disruption can be assayed by measuring resistance to AnxA5 anticoagulant activity. We therefore investigated whether the presence of these β2GPI-dependent LACs might correlate with the disruption of AnxA5 anticoagulant activity. We performed a double blind study with 30 patients divided into three groups; Group A: plasma of patients that show a β2GPI-dependent LAC; Group B: plasma of patients that show a β2GPI-independent LAC; Group C: plasma of SLE patients without a LAC. As previously demonstrated, we were able to discriminate between a β2GPI-dependent and a β2GPI-independent LAC by titrating cardiolipin into the plasma sample. A β2GPI-dependent LAC could be normalized by the addition of cardiolipin in contrast to a β2GPI-independent LAC which was prolonged by cardiolipin. To investigate the effects on AnxA5, we performed an APPT-based coagulation assay. In this assay we added AnxA5 to the plasma of patients and measured the prolongation in clotting time. We calculated the ratio of the clotting time divided by the clotting time with AnxA5 added to the plasma (=AnxA5 ratio). This assay represents the resistance against AnxA5 and gives an indication of its effect on the anticoagulant shield formed by AnxA5. Eleven patients displayed a β2GPI-dependent LAC (group A, all thrombosis), that gave an AnxA5 ratio of 151.3% (± SD 14.5). For 9 patients that displayed a β2GPI-independent LAC (group B, thrombosis n=3) we found a ratio of 225.4% (± SD 29.4). Ten patients did not have LAC (group C, thrombosis n=2) that gave a ratio of 219.2% (± SD 31.0). The annexin A5 ratio of group A was significantly lower than the ratio of group B (P=0.0002) and group C (P=0.0001). There was no difference in AnxA5 ratio between group B and group C (P=0.7802). β2GPI-dependent LAC correlate strongly with both thrombosis and AnxA5 resistance. The results therefore suggest that anti-β2GPI antibodies that cause LAC, in contrast to aPL antibodies with other specificities, are capable of disrupting the anticoagulant effect of AnxA5 on phospholipids. The disruption of the AnxA5 anticoagulant shield by LAC-causing anti-β2GPI antibodies may be a mechanism for thrombosis in APS and offers a potential explanation for the LAC paradox. Figure Figure

Prothrombin as cofactor for antiphospholipids

Lupus ◽  
1998 ◽  
Vol 7 (2_suppl) ◽  
pp. 37-40 ◽  
Author(s):  
M Galli ◽  
T Barbui
Keyword(s):  
Clinical Relevance ◽  
Antiphospholipid Antibodies ◽  
Lupus Anticoagulant ◽  
Anticoagulant Activity ◽  
Low Risk ◽  
Immune Recognition ◽  
Clotting Time ◽  
Glycoprotein I ◽  
Russell’S Viper ◽  
Kaolin Clotting Time

Prothrombin is a common antigenic target of antiphospholipid antibodies, since anti-prothrombin antibodies are detected in about 50-90% of the patients. To allow proper immune recognition, prothrombin must be adsorbed on suitable anionic surfaces. The epitope(s) have not yet been identified: the majority of anti-prothrombin antibodies appear to be of poly- or oligoclonal nature. Anti-prothrombin antibodies, either alone or in combination with anti-β2-glycoprotein I antibodies, are responsible for the lupus anticoagulant activity of about 75% of the cases of phospholipid-dependent inhibitors of coagulation. The two antibodies may be discriminated by means of specific coagulation profiles generated by the comparison of the ratio of the Kaolin Clotting Time (KCT) and the dilute Russell's Viper Venom Time (dRVVT): the KCT profile, which mainly reflects the presence of anti-prothrombin antibodies and the dRVVT profile, which is mostly associated with anti-β2-glycoprotein I antibodies. This distinction, although somewhat artificial, may be clinically useful, since the KCT profile identifies patients at low risk to develop thrombosis. Similarly, most of the studies that measured anti-prothrombin antibodies by ELISA failed to find a significant association with thrombosis. In conclusion, the clinical relevance of these antibodies has not yet been established.

Antiphosphatidylethanolamine antibodies and the antiphospholipid syndrome

Lupus ◽  
2009 ◽  
Vol 18 (10) ◽  
pp. 920-923 ◽  
Author(s):  
M Sanmarco ◽  
M-C Boffa
Keyword(s):  
Clinical Features ◽  
Antiphospholipid Syndrome ◽  
Antiphospholipid Antibodies ◽  
Lupus Anticoagulant ◽  
Anticardiolipin Antibodies ◽  
Anionic Phospholipids ◽  
Glycoprotein I ◽  
Antiphosphatidylethanolamine Antibodies

The antiphospholipid antibodies included as laboratory criteria of the antiphospholipid syndrome (APS) are antibodies reacting with anionic phospholipids – anticardiolipin antibodies and lupus anticoagulant – and with β2-glycoprotein I. However, antibodies reacting with phosphatidylethanolamine (aPE), a zwitterionic phospholipid, have also been described to be associated with the main features of APS. The objectives of this review are to describe the characteristics of aPE and to bring attention to recent evidence that aPE are correlated with the main clinical features of APS, notably, in the absence of the laboratory criteria of this syndrome.

Lupus Anticoagulant Activity Is Frequently Dependent on the Presence of β2-Glycoprotein I

1992 ◽  
Vol 67 (05) ◽  
pp. 499-502 ◽  
Author(s):  
Janine D Oostin ◽  
Ronald H W M Derksen ◽  
H Tanja I Entjes ◽  
Bonno N Bouma ◽  
Philip G de Groot
Keyword(s):  
Dose Response ◽  
Plasma Levels ◽  
Antiphospholipid Antibodies ◽  
Lupus Anticoagulant ◽  
Response Curve ◽  
Anticoagulant Activity ◽  
False Negative ◽  
Coagulation Assays ◽  
Glycoprotein I ◽  
Deficient Patient

SummaryAntiphospholipid antibodies (aPL) are defined by anticardioli-pin antibody (aCL) ELISA and prolongation of phospholipid dependent coagulation assays (lupus anticoagulant; LAC). For the binding of aCL to cardiolipin a cofactor, β2-glycoprotein I (β2-GPI), is necessary. We have investigated whether the same cofactor is essential for LAC activity. Plasma from 6 LAC positive patients and 3 controls was depleted from β2-GPI by means of affinity chromatography. From the 6 LAC positive plasmas, 4 became LAC negative (tested with dRWT) when β2-GPI was depleted and became positive again when purified β2-GPI (200 μg/ml) was added. A dose response curve showed that addition of 50 μg/ml β2-GPI to β2-GPI deficient patient plasma, led to a positive dRWT. Depletion of, and addition of β2-GPI to plasma from controls had no effect on the dRWT. Measurement of β2-GPI plasma levels in 19 LAC positive patients, 40 LAC negative patients and 15 controls showed no difference in β2-GPI levels.These results show that a combination of aPL and β2-GPI is essential not only for binding to cardiolipin, but also for LAC activity and imply that low β2-GPI levels (<50 μg/ml) can lead to false negative LAC tests. These observations may lead to new insights in the pathophysiological complications associated with aPL.

Different Anticoagulant and Immunological Properties of Anti-Prothrombin Antibodies in Patients with Antiphospholipid Antibodies

1997 ◽  
Vol 77 (03) ◽  
pp. 486-491 ◽  
Author(s):  
Monica Galli ◽  
Gianluca Beretta ◽  
Maria Daldossi ◽  
Edouard M Bevers ◽  
Tiziano Barbui
Keyword(s):  
Antiphospholipid Antibodies ◽  
Solid Phase ◽  
Anticoagulant Activity ◽  
Immunological Properties ◽  
Anionic Phospholipids ◽  
Glycoprotein I ◽  
The Family ◽  
Coagulation Tests

SummaryLupus anticoagulant (LA) antibodies are acquired inhibitors of coagulation belonging – together with anticardiolipin (aCL) antibodies – to the family of antiphospholipid antibodies. Since LA antibodies affect coagulation reactions via recognition of the complex of lipid-bound prothrombin, they may be better named anti-prothrombin antibodies. We studied their immunological properties in the plasma of 59 patients with antiphospholipid antibodies by means of specific ELISA systems that allowed the characterization of the interaction of these antibodies with human prothrombin and anionic phospholipids. The mode of presentation of prothrombin was found to greatly influence the reactivity of anti-prothrombin antibodies. In fact, when plain polystyrene plates were used to immobilize prothrombin, virtually no binding was observed. Conversely, when prothrombin was coated on high-activated PVC ELISA plates, 34 samples (58%) contained antibodies that recognize human prothrombin in solid phase. In particular, IgG antibodies were found in 21 plasmas and IgM in 22; both IgG and IgM isotypes were present in 9 of these cases. A higher prevalence was observed in the ELISA for the detection of the antibodies directed at the calcium- mediated complex of phosphatidylserine (PS)-bound prothrombin: 53 samples (90%), preadsorbed with cardiolipin liposomes to remove aCL antibodies, showed the presence of IgG and/or IgM anti-prothrombin antibodies. When the results were analyzed according to the immunoglobulin isotypes, 44 (75%) and 39 (66%) samples were found to contain IgG and IgM anti-prothrombin antibodies, respectively. Both IgG and IgM were present in the plasma of 30 patients. Only half of these samples reacted also with PVC-bound prothrombin. Apparently, the higher rate of positivity of the ELISA for the detection of antibodies to the complex of PS-bound prothrombin was not due to differences in the amount of antigen available in the 2 systems, as judged by binding experiments performed with a rabbit polyclonal anti-human prothrombin antiserum.Finally, the anticoagulant properties of 14 total IgG preparations (12 of them contained anti-prothrombin antibodies positive in both ELISA systems, whereas the other 2 cases reacted either with PVC-bound prothrombin only or with PS-bound prothrombin only) were evaluated by diluted Russell’s Viper Venom Time and by diluted activated Partial Thromboplastin Time. To rule out the β2-glycoprotein I (β2-GPI)-de- pendent anticoagulant effect of the aCL antibodies contained in the preparations, the coagulation tests were performed in (β2-GPI deficient plasma. Six preparations failed to show anticoagulant activity in both assay systems, suggesting that 2 types of IgG anti-prothrombin antibodies exist, that differ with respect to their anticoagulant properties. These findings suggest that anti-prothrombin antibodies resemble aCL antibodies with respect to the behaviour in “in vitro” coagulation reactions and underline the wide heterogeneity of antiphospholipid antibodies.

IgG antibodies that recognize epitope Gly40-Arg43 in domain I of β2–glycoprotein I cause LAC, and their presence correlates strongly with thrombosis

Blood ◽  
2005 ◽  
Vol 105 (4) ◽  
pp. 1540-1545 ◽  
Author(s):  
Bas de Laat ◽  
Ronald H. W. M. Derksen ◽  
Rolf T. Urbanus ◽  
Philip G. de Groot
Keyword(s):  
Lupus Anticoagulant ◽  
Anticoagulant Activity ◽  
Type A ◽  
Full Length ◽  
Enzyme Linked Immunosorbent Assay ◽  
Igg Antibodies ◽  
Type B ◽  
Glycoprotein I ◽  
Heterogeneous Reactivity ◽  
Domain I

AbstractAnti–β2–glycoprotein I antibodies are known to have a heterogeneous reactivity against β2–glycoprotein I. We performed this study to characterize the epitope on β2–glycoprotein I to which pathologic anti–β2–glycoprotein I antibodies are directed. Plasma samples from 198 patients with various systemic autoimmune diseases were tested for the presence of lupus anticoagulant and anti–β2–glycoprotein I immunoglobulin G (IgG) antibodies. The reactivity of the anti–β2–glycoprotein I–positive samples was further tested by coating recombinant full-length β2–glycoprotein I and 8 deletion mutants of β2–glycoprotein I onto hydrophilic and hydrophobic enzyme-linked immunosorbent assay (ELISA) plates. Full-length β2–glycoprotein I with point mutations in domain I at positions 8, 40, and 43 were used in inhibition experiments. Fifty-two patients with anti–β2–glycoprotein I IgG antibodies could be divided into 2 patterns. Type A antibodies only recognize domain I when coated onto hydrophobic plates; they do not recognize domain I coated onto hydrophilic plates. Type B antibodies have heterogeneous reactivity for all domains. Type A antibodies recognize the epitope around amino acids Gly40-Arg43 and cause lupus anticoagulant activity. In contrast to type B antibodies, those of type A strongly correlated with thrombosis. In conclusion, antibodies directed at domain I (epitope comprising Gly40 and Arg43) have lupus anticoagulant activity and strongly associate with thrombosis.

Anti-β2 Glycoprotein I Antibodies and Platelet Activation in Patients with Antiphospholipid Antibodies: Association with Increased Excretion of Platelet-Derived Thromboxane Urinary Metabolites

1998 ◽  
Vol 79 (01) ◽  
pp. 42-45 ◽  
Author(s):  
Ricardo Forastiero ◽  
Marta Martinuzzo ◽  
Jacques Maclouf ◽  
Luis Carreras
Keyword(s):  
Urinary Excretion ◽  
Platelet Activation ◽  
Antiphospholipid Antibodies ◽  
Glycoprotein I ◽  
Number Of Patients ◽  
Increased Risk ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
Normal Controls

SummaryPlatelet activation may contribute to the increased risk of thrombotic complications in patients with antiphospholipid antibodies (aPL). The increased urinary excretion of 11-dehydro-thromboxane B2 (11-DH-TXB2) reported in patients with lupus anticoagulant (LA) and/or anticardiolipin antibodies (aCL) reflects in vivo platelet activation. However the majority of autoimmune aPL are directed to β2 glycoprotein I (β2GPI) or prothrombin (II). We investigated the relationship of these antibodies with 11-DH-TXB2 urinary excretion in 34 patients with aPL. The urinary 11-DH-TXB2 was measured by EIA after extraction on octadecyl columns and purification on silica gel columns, which was validated by thin-layer chromatography/EIA procedure. A significantly increased excretion of 11-DH-TXB2 was found in aPL patients as compared to 18 normal controls (p <0.01). But no differences were seen in the excretion of 11-DH-TXB2 between patients with or without LA, or aCL. The number of patients with anti-II antibodies was too small to draw any conclusion. In contrast, patients with anti-β2GPI antibodies IgG at moderate/high titre (group A, n = 14) had higher levels of urinary 11-DH-TXB2 than those at low titre or negative (group B, n = 20) (p = 0.01). The group A of patients presented an increase in 11-DH-TXB2 compared to controls (p <0.001), but no statistically significant difference was found between patients from the group B and normal controls. A correlation between levels of urinary 11-DH-TXB2 and titre of antibodies was only found for anti-β2GPI-IgG (rs = 0.51, p <0.005). Our data show that the observed platelet activation in aPL patients is related to the presence of antibodies reacting with β2GPI.

scholarly journals Lupus anticoagulant activity of some antiphospholipid antibodies against phospholipid bound beta 2 glycoprotein I.

1993 ◽  
Vol 46 (7) ◽  
pp. 665-667 ◽  
Author(s):  
D M Keeling ◽  
A J Wilson ◽  
I J Mackie ◽  
D A Isenberg ◽  
S J Machin
Keyword(s):  
Antiphospholipid Antibodies ◽  
Lupus Anticoagulant ◽  
Anticoagulant Activity ◽  
Glycoprotein I ◽  
Beta 2
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