Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02749 (beta2-glycoprotein I)
 836 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anticardiolipin antibodies (aCL) were recently discovered to recognize a complex consisting of phospholipids and apolipoprotein H (apo H). In this study, we determined the serum apo H levels in 36 systemic lupus erythematosus (SLE) patients with or without antiphospholipid antibodies (aPL), including aCL and lupus anticoagulants, to clarify the possible effects of aPL on apo H levels in vivo. The apo H levels were low in SLE patients as compared with 22 healthy controls. However, no associations were found between apo H levels and circulating aPL or clinical features of the antiphospholipid antibody syndrome. A secondary hyperlipidemic state, which probably related to lupus nephritis (proteinuria) and/or prednisolone treatment, increased apo H levels in SLE patients.
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PMID:Serum apolipoprotein H levels in systemic lupus erythematosus are not influenced by antiphospholipid antibodies. 130 75

The clinical and serological features of 38 aCL-positive patients were compared to those of 45 aCL-negative patients. A significantly higher incidence of thrombophlebitis and livedo reticularis was found in aCL-positive patients. There were 13 aCL positive patients with thrombophlebitis and/or arterial thromboses and these 13 patients were designated as having the antiphospholipid syndrome (APS) while the remaining 70 patients were diagnosed as having Systemic Lupus Erythematosus (SLE). APS patients also had a high incidence of arterial occlusions, recurrent abortions and strokes compared to SLE patients. Patients with high levels of IgG-aCL were more likely to have APS, while patients with low levels of IgG-aCL or IgM-aCL only were more likely to have SLE without the clinical features of APS. Since aCL antibodies have recently been shown to interact with a phospholipid-binding plasma protein beta 2-glycoprotein-I (beta 2-GPI), we measured the beta 2-GPI levels in these patients and found that beta 2-GPI levels are significantly higher in APS compared to SLE patients negative for aCL antibodies. Since beta 2-GPI is known to exert multiple effects on coagulation processes the interaction of aCL antibodies with this glycoprotein may play a pathogenic role in APS.
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PMID:Patients with anticardiolipin antibodies with and without antiphospholipid syndrome: their clinical features and beta 2-glycoprotein-I plasma levels. 151 96

A plasma protein is required as a cofactor for the binding of antiphospholipid antibodies to phospholipids. This protein has been identified as beta 2-glycoprotein I, an apolipoprotein that binds to negatively charged phospholipids and is a natural inhibitor of the coagulation cascade. It is not certain whether antiphospholipid antibodies bind to beta 2-glycoprotein I alone, to beta 2-glycoprotein I-phospholipid complex, or to a phospholipid epitope modified by beta 2-glycoprotein I. We used isolated beta 2-glycoprotein I and purified IgG and IgM antiphospholipid antibodies from serum or plasma of patients with the antiphospholipid syndrome to study the relation between antiphospholipid antibodies and beta 2-glycoprotein I in enzyme-linked immunosorbent assays. IgG antiphospholipid antibodies did not bind to beta 2-glycoprotein I when it was used as an antigen on the assay plate. The binding of IgG and IgM antiphospholipid antibodies to phospholipid was enhanced when beta 2-glycoprotein I was added to the phospholipid antigens either before or together with the antiphospholipid antibodies. The degree of enhancement varied across patients. IgM antiphospholipid antibodies required less cofactor for binding to phospholipid antigens. These results confirm the requirement of beta 2-glycoprotein I as a cofactor for the binding of autoimmune antiphospholipid antibodies to phospholipids.
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PMID:Antiphospholipid cofactor. 144 Jul 26

NZW x BXSB F1 (W/B F1) male mice develop systemic lupus-like disease, and several autoantibodies, circulating immune complexes, and lupus nephritis become apparent. The abnormally high incidence of degenerative coronary vascular disease with myocardial infarction and thrombocytopenia due to the presence of both platelet-associated antibodies and circulating antiplatelet antibodies in this animal has been reported. We found that W/B F1 male mice produced autoantibodies against cardiolipin (aCL) and that the titer of aCL increases with age. aCL from W/B F1 male mice were mainly IgG and binding activity to cardiolipin was aCL-cofactor (beta 2-glycoprotein I (beta 2-GPI)) dependent. We developed monoclonal aCL from these animals and examined specificity of the autoantibodies. All the mAb used reacted with the negatively charged phospholipids, cardiolipin, phosphatidylserine, and phosphatidylinositol, and some reacted with platelets and DNA. The addition of human or mouse beta 2-GPI enhanced the titer for monoclonal aCL from the W/B F1 mice. From the results of competitive inhibition enzyme immunoassay with monoclonal aCL and purified beta 2-GPI, aCL from the W/B F1 mice recognized the complex of CL and beta 2-GPI. The W/B F1 male mouse may be an appropriate model for use in studies on the pathologic significance of aCL in patients with antiphospholipid syndrome.
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PMID:Anticardiolipin antibodies in NZW x BXSB F1 mice. A model of antiphospholipid syndrome. 163 62

New details have been added to the description of the antiphospholipid antibody syndrome. These include quantitation of risk of stroke; delineation of an associated acute occlusive vasculopathy syndrome, including its pathology; increased awareness of the association of adrenal insufficiency with antiphospholipid antibody; new demonstration of placental pathology in cases of fetal death; and new details on the persistence or transience of antibody in patients with systemic lupus erythematosus. There are several animal models for the antiphospholipid antibody syndrome. Assay standardization and reproducibility issues, more for the lupus anticoagulant than for the enzyme-linked immunosorbent assay for antiphospholipid antibody, remain as important barriers to progress. Antibody characteristics of activity, isotype, and subclass must be considered in assay interpretation; antigen characteristics of fatty acid chain and lipid phase are also important variables. Other circulating proteins may have clinical importance. Several laboratories have commented that antiphospholipid antibody interferes with protein C. A cofactor, apolipoprotein H, enhances binding of some antiphospholipid IgG antibodies. Other phospholipid-binding proteins are known. Isolation, purification, and perhaps cloning of many of these factors should lead to a better understanding of the pathogenesis of the syndrome.
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PMID:Antiphospholipid antibody and antiphospholipid antibody syndrome. 183 43

An 18-year-old woman with primary antiphospholipid syndrome developed a major cerebral infarction leading to brain death despite intensive treatment with steroids, urokinase, glyceol and heparin. Fatal strokes associated with this syndrome are rare. A computed tomographic scan of the brain suggested occlusion of the main trunk of the right middle cerebral artery. The titer of antibodies against cardiolipin/ beta 2-glycoprotein I complex in serum was extremely high.
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PMID:Fatal cerebral infarction in an asymptomatic young patient with primary antiphospholipid syndrome. 750 May 48

Anticardiolipin antibodies (aCL) derived from the sera of individuals exhibiting the antiphospholipid syndrome (APS) directly bind to beta 2-glycoprotein I (beta 2-GPI), which is adsorbed to an oxidized polystyrene surface. Oxygen atoms were introduced on a polystyrene surface by irradiation with electron or gamma-ray radiation. X-ray photoelectron spectroscopy revealed the irradiated surfaces were oxidized to generate C-O and C = O moieties. aCL derived from either APS patients or (NZW x BXSB)F1 mice bound to beta 2-GPI coated on the irradiated plates, depending on the radiation dose. Antibody binding to beta 2-GPI on the irradiated plates was competitively inhibited by simultaneous addition of cardiolipin (CL)-coated latex beads mixed together with beta 2-GPI but were unaffected by addition of excess beta 2-GPI, CL micelles, or CL-coated latex beads alone. There was a high correlation between binding values of aCL in sera from 40 APS patients obtained by the anti-beta 2-GPI enzyme-linked immunosorbent assay (ELISA) using the irradiated plates and those by the beta 2-GPI-dependent aCL ELISA. Therefore, aCL have specificity for an epitope on beta 2-GPI. This epitope is expressed by a conformational change occurring when beta 2-GPI interacts with an oxygen-substituted solid phase surface.
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PMID:Anticardiolipin antibodies recognize beta 2-glycoprotein I structure altered by interacting with an oxygen modified solid phase surface. 750 6

The antiphospholipid antibodies (aPL) present in autoimmune disorders are associated with thromboembolic episodes, and their binding to phospholipids (PL) is mediated by a plasma cofactor, beta 2-glycoprotein I (beta 2GPI). Both PL and beta 2GPI seem necessary for binding, thus indicating that the two components comprise the epitope against which aPL are directed. Using an anti-beta 2GPI antibody ELISA with the antigen adsorbed onto polyvinylchloride (PVC) plates, we detected high antibody titres in 12 out of 12 plasma from patients with the antiphospholipid syndrome. No or very low positivity was obtained when the same ELISA was carried out in polystyrene (PST) plates, while an increasing positivity was found when processed (i.e. more hydrophilic) or COOH-surface PST plates were used. When beta 2GPI dependent IgG-aPL were purified using agarose-immobilized cardiolipin, 4 out of 4 preparations were highly positive in anti-beta 2GPI antibody ELISA using PVC plates, while beta 2GPI was not fully recognized by aPL-IgG when adsorbed onto PST plates. These findings demonstrate that aPL are, in fact, anti-beta 2GPI antibodies directed against a cryptic epitope which is expressed when beta 2GPI is bound to anionic phospholipid, or another suitable surface.
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PMID:Autoimmune antiphospholipid antibodies are directed against a cryptic epitope expressed when beta 2-glycoprotein I is bound to a suitable surface. 753 19

We studied and characterized anti-bovine beta 2-glycoprotein I antibodies (aB beta 2-GPI) in sera from patients with antiphospholipid syndrome (APS) by ELISA. Bovine beta 2-glycoprotein I (beta 2-GPI) was purified by heparin affinity and DEAE ion-exchange chromatography, and identified on immunoblots using a monoclonal antibody against human beta 2-GPI and by amino acid sequence analysis. aB beta 2-GPI levels in the sera from 36 APS patients were measured by ELISA using purified bovine beta 2-GPI as an antigen. The mean +/- standard deviation level of aB beta 2-GPI was 17.4 +/- 22.0 units in the 58% of APS patients who were positive. There was a significant correlation (P = 0.003) between aB beta 2-GPI and anticardiolipin antibody (aCL) levels. aB beta 2-GPI from the sera of patients with APS was inhibited by bovine beta 2-GPI itself. Purified IgG from the sera of patients with APS showed that bovine beta 2-GPI was capable of acting as a cofactor for aCL. Purified bovine beta 2-GPI was useful antigen for conventional ELISA. aB beta 2-GPI may contribute to the further development of aCL analysis and to the understanding of the pathogenesis of APS.
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PMID:Detection of anti-bovine beta 2-glycoprotein I antibody in sera from patients with antiphospholipid syndrome. 765 60

A 26-year-old man with systemic lupus erythematosus (SLE) and a history of acute myocardial infarction developed portal hypertension accompanied by abnormal liver function and esophageal varices. As his clinical course suggested the possibility of antiphospholipid syndrome, a titer of anticardiolipin antibody (aCL) was serially measured using an enzyme immunoassay with beta 2-glycoprotein I as a cofactor. The titer of aCL increased with the development of portal hypertension, and promptly decreased with the improvement of liver function just after corticosteroid therapy. The long-term course in this case suggests that aCL may cause portal hypertension associated with SLE.
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PMID:Portal hypertension associated with anticardiolipin antibodies in a case of systemic lupus erythematosus. 765 97


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