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

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.
Stroke 1992 Feb
PMID:Antiphospholipid cofactor. 144 Jul 26

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.
 ...
PMID:Antiphospholipid antibody and antiphospholipid antibody syndrome. 183 43

Clinical and serological features in SLE patients with arterial or venous thrombosis were studied. The subjects consisted of 140 patients with SLE who met the revised criteria for the classification of SLE by the American Rheumatism Association. Forty patients (29%) had arterial or venous thrombosis. Arterial thrombosis such as stroke was found in 30 patients, and venous thrombosis such as deep vein thrombosis was seen in 24 patients. Average age at the disease onset was 34.5 +/- 12.5 years old. Renal disorder was found as a clinical feature, and IgG anticardiolipin antibodies (aCL), IgG phospholipid-dependent anti-beta 2-glycoprotein I (beta 2-GPI) antibodies and IgG anti-Annexin V antibodies were identified as serological features in SLE patients with thrombosis. These patients were diagnosed as having antiphospholipid syndrome. It was necessary to perform primary prevention therapy as well as secondary prevention therapy. Multiple thrombotic events in the past history and sustained positive reactions of IgG aCL were suggested as predictors of recurrent thrombosis. These data indicated the clinical and serological characteristics in SLE patients with arterial or venous thrombosis.
 ...
PMID:[Thrombosis in patients with SLE and antiphospholipid syndrome]. 778 37

IgG antibodies to cardiolipin and beta 2-glycoprotein I were looked for using an enzyme-linked immunosorbent assay (ELISA) in 19 patients with giant cell arteritis (meeting 1990 American College of Rheumatology criteria), including 16 with concomitant polymyalgia rheumatica (meeting Bird's criteria) and in three patients with isolated polymyalgia rheumatica. IgG anti-cardiolipin antibodies were demonstrated in eight patients (36%) and IgG anti-beta 2-glycoprotein I antibodies in two patients (9%) including one without anti-cardiolipin antibodies. Titers of anti-cardiolipin antibodies ranged from 27 to 190 units of IgG antiphospholipid antibodies (UGPL) (mean 71 UGPL). Of the eight patients with anti-cardiolipin antibodies, two had giant cell arteritis without polymyalgia rheumatica and six had polymyalgia rheumatica with clinical (n = 2) or histologic (n = 4) evidence of giant cell arteritis. None of the three patients with polymyalgia rheumatica but no giant cell arteritis had anti-cardiolipin or anti-beta 2 glycoprotein I antibodies. The VDRL was negative in the 14 patients who had this test. Tests for lupus anticoagulant were performed routinely, always with negative results. Among giant cell arteritis patients, those who tested positive for anticardiolipin antibody had significantly higher values for the erythrocyte sedimentation rate (p < 0.006) and for serum C-reactive protein (p < 0.03) and fibrinogen values (p = 0.05), and a trend toward higher platelet counts, as compared to those who tested negative for anticardiolipin antibody. The mean daily prednisone dose at the time of sampling was significantly lower in giant cell arteritis patients with anti-cardiolipin antibodies (p < 0.05); this difference may account for the apparent correlation between anti-cardiolipin antibodies and laboratory markers for inflammation. These data, as well as findings from serial measurements, suggest that anti-cardiolipin antibodies are present early in the course of giant cell arteritis and disappear within a few weeks of initiation of corticosteroid therapy in a dose of more than 25 mg prednisone per day. In this study, only one patient without anticardiolipin antibodies developed a cerebrovascular accident. Positive tests for anti-cardiolipin antibody or anti-beta 2 glycoprotein I antibody in a patient with polymyalgia rheumatica suggest a diagnosis of concomitant giant cell arteritis, which is usually symptomatic.
 ...
PMID:Antibodies to cardiolipin and beta 2 glycoprotein I in patients with polymyalgia rheumatica and giant cell arteritis. 873 42

There has been a recent, dramatic surge in interest in antiphospholipid antibodies and associated clinical disorders, especially focal ischemic cerebrovascular disease. Antiphospholipid antibodies are a heterogeneous group of antibodies with varying specificities. Coagulation assays will detect lupus anticoagulants while enzyme-linked immunosorbent assays detect anticardiolipin antibodies. There are numerous potential links between antiphospholipid antibodies and coagulation disorders, including interaction of antiphospholipid antibodies and a cofactor, beta 2-glycoprotein I, which itself is involved in coagulation mechanisms. While the specific mechanism of antiphospholipid antibody-related coagulopathy is unknown, it is clear that antiphospholipid antibodies are associated with an immune-mediated prothrombotic state. Patients with the highest titers of IgG antiphospholipid antibodies have a relatively high risk of recurrent thrombotic events, especially stroke, deep venous thrombosis, and spontaneous abortion. Because of limited controlled, prospective data, current therapy remains empiric and directed at coagulation mechanisms, immune mechanisms, or both.
 ...
PMID:Cerebrovascular disease with antiphospholipid antibodies: immune mechanisms, significance, and therapeutic options. 896 22

In HIV-1 infection, an increased prevalence of anticardiolipin autoantibodies (aCL) and lupus anticoagulant (LA) has been described. In order to see if these antibodies are isolated or, like in autoimmune diseases, associated with hematological disorders and with antibodies to other phospholipids and to proteins of coagulation, we investigated 3 groups of patients: 1. 342 HIV-1 infected patients, 2. 145 control patients including 61 systemic lupus erythematosus (SLE) patients, 58 patients with a connective tissue disease, 15 patients with stroke, 11 patients with syphilis and 3. 100 blood donors. In HIV-1 infection antiprothrombin (aPrT) antibodies were present in 2% of patients, the prevalence of antiphosphatidylcholine antibodies (aPC) (50%) was almost as high as aCL (64%), and 39% had both antibodies. Absorption on liposomes of the latter revealed an heterogeneous mixture of aCL and aPC or cross-reacting antibodies. In contrast with SLE, anti-beta 2-glycoprotein I (4%), LA (1%), biological false positive test for syphilis (0.3%), thrombosis (p < 0.001) were uncommon. In HIV-1 infection, antiphospholipid antibodies do not associated with features linked to them in SLE or syphilis.
 ...
PMID:Autoantibodies to phospholipids and to the coagulation proteins in AIDS. 918 92

The antiphospholipid syndrome is a disorder characterized by recurrent thrombosis and the presence of antibodies specific to phospholipids. However, the diagnosis of this syndrome is hampered by the lack of a specific laboratory test. In this study an ELISA for the measurement of antibodies to solid-phase beta2-glycoprotein I (beta2-GPI) was established and compared with anticardiolipin antibodies for diagnosis of antiphospholipid syndrome. Significantly elevated levels of antibodies to beta2-GPI were found in all patients with definite antiphospholipid syndrome (median = 91 AU). Marginally elevated levels of antibodies to beta2-GPI were observed in 5% of patients with systemic lupus erythematosus (SLE; median = 4 AU), 1% with stroke (median = 3 AU), 13% with infectious mononucleosis (median = 3 AU), 10% with HIV infection (median = 3 AU) and 8% with VDRL false-positive serology for syphilis (median = 4 AU), but not in patients with rheumatoid factor, syphilis or carotid artery stenosis. In contrast, significantly raised levels of anticardiolipin antibodies were observed in 100% of patients with definite antiphospholipid syndrome, 30% with SLE, 88% with HIV infection, 94% with syphilis, 62% with infectious mononucleosis, 9% with rheumatoid factor-positive sera, 74% VDRL false-positive serology for syphilis, 47% with stroke and 0% with carotid artery stenosis. This solid-phase assay for antibodies to beta2-GPI is highly specific for the antiphospholipid syndrome and represents an advance in the laboratory diagnosis of this disorder.
 ...
PMID:Antibodies to beta2-glycoprotein I--a specific marker for the antiphospholipid syndrome. 927 26

Antiphospholipid antibodies associated with the antiphospholipid syndrome (APS) have been shown to bind plasma proteins, particularly beta 2-glycoprotein I (beta2-GPI). In this study the incidence of antibodies to solid-phase prothrombin was examined in patients with antiphospholipid syndrome and a variety of other inflammatory disorders. Significantly elevated levels of IgG anti-prothrombin (anti-PT) antibodies were detected in 63% of patients with APS (n = 27, median 22 arbitrary units: AU), 33% with SLE (n = 92, median 14 AU). 45% with rheumatoid factor (n = 22, median 16 AU), 21% with carotid artery stenosis (n = 21, median 15 AU), 32% with stroke (n = 38, median 13 AU). 67% of patients with a false positive serology for syphilis (n = 21, median 24 AU), 37% with HIV (n = 30, median 14 AU), 29% with syphilis (n = 14, median 19 AU) and 3% with infectious mononucleosis (n= 30, median 9 AU). In addition, a group of lupus anticoagulant (LA) positive patients (n = 48) was examined for antibodies to prothrombin, beta2-GPI and cardiolipin. 10 (21%) patients had raised levels of IgG anti-PT antibodies, 30 (62%) had significantly elevated levels of anti-beta2-GPI antibodies and 15 (31%) had elevated levels of anticardiolipin antibodies (ACA). Of the LA-positive patients, 15 (43%) were identified with definite APS, eight (23%) with probable APS, two (6%) with possible APS and 10 (28%) patients had no clinical evidence of APS. In conclusion, antibodies to prothrombin were found in a variety of inflammatory disorders and were therefore not specific for the APS. However, identification of the plasma proteins recognized by antibodies from patients with APS may provide insight into the pathogenic mechanisms involved in the heterogenous clinical manifestations of the APS.
 ...
PMID:Antibodies to prothrombin in antiphospholipid syndrome and inflammatory disorders. 973 36

Our study was undertaken to investigate whether beta2-glycoprotein I (GPI) is relevant for enhancing anticardiolipin antibody (aCL) binding in stroke patients, in particular view of vascular risk factors and recurrence of previous cerebral ischemic events. One-hundred and twenty-one sera from patients with ischemic stroke and 154 control sera from patients with non-ischemic neurological disorders (n = 43) and healthy subjects (n = 111) were included in the study. All sera were tested for either GPI-independent aCL and GPI-dependent aCL. GPI-independent aCL were detected in two (1.7%) stroke patients. When GPI was added to the assay system, 13 (10.8%) sera were positive. Of the 43 sera in the neurological control group one was positive for both GPI-independent aCL and GPI-dependent aCL. Multiple linear regression in the stroke group revealed that GPI-dependent aCL are marginally associated with sex, prior TIA/strokes and embolism. More importantly, GPI-dependent aCL were significantly more frequent in stroke patients with a history of prior TIA/strokes compared with patients with a first ischemic stroke (p = 0.029). The present study demonstrates that aCL in stroke patients are of the GPI-dependent type and emphasizes the importance of adding GPI in the immunoassay for the optimal detection of aCL. Furthermore, it supports the recommendation of testing aCL in those patients who experience unexplained recurrent cerebral ischemic events.
 ...
PMID:beta2-Glycoprotein I - dependent anticardiolipin antibodies in ischemic stroke. 1021 Aug 9

We report a case of acute adrenal insufficiency in a context of probable bilateral adrenal haemorrhage, as revealed by CT-scan in a 52-year-old woman with a history of spontaneous abortion and repeated ischaemic stroke without symptoms or signs of collagen vascular disease. The symptoms began after the patient had successfully been treated for pneumonia. She had persistently high titres of IgG anticardiolipin antibodies, antibodies against beta 2-glycoprotein I and a lupus anticoagulant. The diagnosis of primary antiphospholipid syndrome with adrenal insufficiency was postulated.
 ...
PMID:[Bilateral adrenal hemorrhage with adrenal insufficiency in the framework of primary antiphospholipid antibody syndrome]. 1082


1 2 3 Next >>