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Query: UMLS:C0409974 (lupus)
 22,386 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In recent years, clinical syndromes involving lupus anticoagulants and antiphospholipid antibodies have come into increasing clinical prominence. Since the discovery that most antiphospholipid antibodies require the presence of anionic phospholipid-binding proteins such as B2-glycoprotein I and prothrombin, a large number of studies have attempted to delineate the specificity of these antibodies. Several mechanisms have been proposed to explain the hypercoagulable state associated with these antibodies. This review attempts to summarize these data and the challenges that confront efforts to delineate the pathogenesis of the prothrombotic state associated with the presence of these antibodies.
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PMID:Lupus anticoagulants and antiphospholipid antibodies. 992 31

The objective of this study was to look for the occurrence of catastrophic antiphospholipid syndromes (APS) and to try to detect discriminating factors for predicting a worse prognosis, related to Lupus anticoagulant (LA) and antiphospholipid antibodies (aPL), in systemic lupus erythematosus (SLE) with main renal involvement. Regression, recursive partition and logistic regression analyses were applied to our 80 SLE patients prospectively followed up since 1980. Immunologic and other laboratory parameters including beta 2-glycoprotein 1 dependence, resistance to activated protein C caused by a substitution on the coagulation factor V gene, induction of monocyte procoagulant activity. Regression studies demonstrated an overall worse prognosis in term of both thrombosis and death for the group of LA/aPL positive patients (33/80). However, recursive partition analysis was able to isolate a small high risk-subgroup (8/33) characterized by persistent LA/aPL antibodies positive result, widespread signs of noninflammatory vasculopathy (skin, brain, kidney) and renal pathology mimicking that of thrombotic microangiopathy or arteriolosclerosis, also in the absence of classic SLE-nephritis. Only in this subset, three catastrophic APS were recorded, while, in traditional SLE nephritis, even persistent LA/aPL positive results (sometimes after one previous thrombosis) did not seem to imply a particularly severe prognosis. All serologic criteria employed are unable to identify high-risk patients. We conclude that catastrophic APS is a rare event in renal SLE. Before more predictive serologic markers become available, a simple algorithm, dealing with clinical data and renal histologic patterns, may help physicians to identify putatively high risk-LA/aPL antibodies in SLE patients with main renal involvement. This ominous subset does not belong to the group of classic SLE-nephritis.
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PMID:Catastrophic antiphospholipid syndromes in systemic lupus erythematosus. 1004 17

Lysophosphatidylcholine (LPC) is present in oxidized low density lipoprotein (oxLDL), which is implicated in atherosclerosis. Antibodies to cardiolipin (aCL) and oxLDL (aoxLDL) have been shown to crossreact. LPC is formed by hydrolysis of phosphatidylcholine (PC) in LDL and cell membranes, induced by phospholipase A2 or by oxidation. We here demonstrate the presence of enhanced antibody levels to LPC in 184 patients with SLE as compared to 85 healthy, age-matched controls. The antibody reactivity to LPC was not specifically related to oxidation of the fatty acid moiety in LPC, since LPC containing only the saturated fatty acid palmitic acid showed equivalent antibody levels as LPC containing unsaturated fatty acids. aPC were significantly lower as compared to aLPC, indicating that hydrolysis of PC at the sn-2 position increases the antigenic potential of the molecule. Beta-glycoprotein 1 was a cofactor for aCL, but not for aoxLDL or aLPC, and the antigenicity of these compounds is therefore not directly related to beta2GP1. There was a close correlation between aoxLDL, aCL and aLPC and both LPC and oxLDL competitively inhibited aCL-binding to CL. LPC, oxLDL and CL thus display a common antigenic site, which could be formed by removal of a fatty acid at the sn-2 position, possibly due to the activity to phospholipase A2 and/or oxidation. This study indicates the potential role of LDL-oxidation and phospholipase A2 in SLE.
Lupus 1999
PMID:Antibodies against lysophosphatidylcholine and oxidized LDL in patients with SLE. 1019 9

Antiphospholipid antibodies (aPL), including antibodies detected in anti-cardiolipin (aCL) enzyme-linked immunosorbent assays and in lupus anticoagulant (LA) tests, are strongly associated with recurrent thrombosis and recurrent fetal loss, i.e. the antiphospholipid syndrome (APS). Although recent studies suggest that most APS-associated aCL are directed against the phospholipid (PL)-binding plasma protein beta2-glycoprotein 1 (beta2GP1), the precise nature of aCL binding specificities remains controversial. To address the issue of aCL specificity we generated five new monoclonal IgG aCL from two patients with APS. Characterization of these five aCL, as well as two previously published IgG aCL, revealed three patterns of reactivity: (1) four antibodies reacted strongly with human beta2GP1-cardiolipin (CL) complexes and weakly with human beta2GP1 alone; (2) two antibodies recognized bovine beta2GP1, but not human beta2GP1; (3) one antibody reacted with complexes of human beta2GP1 and CL, but not with human beta2GP1 alone. Only one monoclonal displayed weak LA activity. These patient-derived IgG monoclonal antibodies, and additional ones to be generated, may help define varying species of antibodies detected in aCL assays and identify the specific antibodies that may be pathogenic.
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PMID:Characterization of IgG monoclonal anti-cardiolipin/anti-beta2GP1 antibodies from two patients with antiphospholipid syndrome reveals three species of antibodies. 1023 71

It has been suggested that patients with clinical features suggestive of antiphospholipid syndrome but being lupus anticoagulant (LA) and anticardiolipin (aCL) negative, should be tested for antibodies to beta(2) glycoprotein-I (abeta(2)GP-I), a protein involved in the binding of antiphospholipid antibodies (aPL) to phospholipid surfaces. This was investigated in the present study where a total of 385 women aged </=40 years were included. Of these, 175 were experimental subjects and 210 were controls. The former comprised the following two study groups: 100 spontaneous recurrent aborters (group one), and 75 patients with repeated failure of embryo transfer (group two). Controls included three groups of women: 100 normal healthy parous women with no previous abortion (group three), 60 infertile patients achieving a live birth with their first in-vitro fertilization (IVF)/embryo transfer attempt (group four), and 50 patients with recurrent abortion who tested positive for aPL (LA and/or aCL) (positive controls, group five). Only one patient among recurrent aborters (group one) tested positive for abeta(2)GP-I. All women in groups two, three and four were negative for abeta(2)GP-I screening. As expected, prevalence of patients testing positive for abeta(2)GP-I was significantly higher in group five than among the other groups of patients (P < 0.001). No differences were observed regarding the prevalence of abeta(2)GP-I positive sera in the subgroup of patients having aCL and those having the LA in group five. It is concluded that abeta(2)GP-I screening in first-trimester recurrent abortion or in failure of implantation after IVF is not warranted in patients without aPL as detected by standard antiphospholipid assays.
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PMID:Human reproductive failure is not a clinical feature associated with beta(2) glycoprotein-I antibodies in anticardiolipin and lupus anticoagulant seronegative patients (the antiphospholipid/cofactor syndrome) 1073 54

Antibodies directed against platelet factor 4-heparin are present in patients with heparin-induced thrombocytopenia (HIT). Additionally, it has been suggested that heparin can be an antigenic target of antiphospholipid antibodies (aPL). We investigated the presence of heparin-platelet factor 4-induced antibodies (HPIA) in 33 patients with aPL. There were 30 patients with lupus anticoagulant, 25 with anticardiolipin antibodies, 21 with anti-beta2 glycoprotein I, and 18 with antiprothrombin antibodies. 20 patients had a history of thrombosis and 19 had received heparin during the last 60 months. We found 7 (21.2%) who had HPIA; 5 of them also had anti-beta2 glycoprotein I antibodies. Four patients had severe thrombocytopenia and suspicion of HIT. Among them, two presented high positive HPIA results, one of them with positive platelet aggregation test. The third patient showed grey zone HPIA and borderline aggregation test and the fourth one had negative results. Among patients without a history of HIT, 2 who had never received heparin presented high positive, one a moderate positive, and one a grey zone HPIA result; all of them with negative aggregation tests. Five positive sera samples were incubated with cardiolipin liposomes in the presence of beta2 glycoprotein I, and whereas an inhibition greater than 50% was achieved in anticardiolipin and anti-beta2 glycoprotein I activities, HPIA results did not change. We demonstrate that HPIA could be frequently found in patients with aPL. They are responsible for HIT in some cases but can also be found in patients who have not received heparin. Whether they predispose patients with aPL to HIT is not known; nevertheless, a close follow-up of heparin treatment in these patients seems to be mandatory.
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PMID:Antiplatelet factor 4--heparin antibodies in patients with antiphospholipid antibodies. 1052 4

Alloimmune antiphospholipid antibodies react with phospholipids and are an epiphenomenon of an infectious disease. Most autoimmune antiphospholipid antibodies recognise phospholipid-protein complexes or proteins, such as beta2 glycoprotein I or prothrombin and are related to the clinical features of the antiphospholipid syndrome. Lupus anticoagulant, anticardiolipin antibodies, antiprothrombin, and anti-beta2 glycoprotein I antibodies were studied in 61 human immunodeficiency virus (HIV) patients, 55 syphilis patients, and 45 selected patients with antiphospholipid syndrome. Lupus anticoagulant was present in 72% of HIV and 81% of antiphospholipid syndrome patients. None of the syphilis patients had lupus anticoagulant. Anticardiolipin antibodies were found at comparable prevalence in the three groups (HIV 67%, syphilis 67%, antiphospholipid syndrome 84%). HIV had more frequently anti-beta2 glycoprotein I (13%) and antiprothrombin (12%) antibodies than syphilis (0 and 4%, respectively), but significantly less than antiphospholipid syndrome (61 and 40%, respectively). Autoimmune antiphospholipid antibodies in HIV without clinical features of antiphospholipid syndrome might be a reflex of the immunological chaos and/or the constant antigenic virus stimulus.
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PMID:Different types of antiphospholipid antibodies in AIDS: a comparison with syphilis and the antiphospholipid syndrome. 1055 81

Antiphospholipid syndrome is characterized by the presence of high titers of anti-beta(2)-glycoprotein I (beta(2)GPI) antibodies, lupus anticoagulant associated with thromboembolic phenomena, thrombocytopenia and recurrent fetal loss. Single-chain Fv (scFv) were prepared from four anti-beta(2)GPI mAb, CAM, CAL, CAR and 2C4C2, and one anti-ssDNA. All five scFv showed the same antigen binding properties as the original mAb. Replacement of the pathogenic CAM V(H) domain with the non-pathogenic CAL V(H) or anti-ssDNA V(H) decreased the binding affinity of the scFv to beta(2)GPI and completely abrogated the anticoagulant activity. Exchanging the CAM V(H) with anti-DNA V(H) resulted in a shift from anti-beta(2)GPI to anti-ssDNA binding of the scFv. Replacement of the CAM V(L) with CAL V(L) did not affect the binding and activity. BALB/c mice were immunized with the anti-beta(2)GPI scFv, and the scFv resulting from the substitution of the heavy (H) and light (L) chains. The mice which were immunized with CAM, 2C4C2 and CAR scFv developed clinical manifestations of experimental anti-phospholipid syndrome. Elevated titers of mouse anti-cardiolipin (aCL), anti-beta(2)GPI, associated with lupus anticoagulant activity, thrombocytopenia, prolonged activated partial thromboplastin time and a high percentage of fetal resorptions were detected, in the CAM scFv group and in the scFv composed of CAM V(H) groups. High titers of aCL, anti-beta(2)GPI, anti-ss/dsDNA and anti-histone associated with lupus findings were observed in the sera of the 2C4C2 scFv-immunized mice. Immunization with CAL scFv did not lead to any clinical findings. The current study shows that scFv of pathogenic antibodies are capable of inducing the same clinical manifestations as the whole antibody molecule upon active immunization. Replacement of H/L chains point to the importance of the V(H) domains in the pathogenic potential of anti-beta(2)GPI.
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PMID:Characteristics and pathogenic role of anti-beta2-glycoprotein I single-chain Fv domains: induction of experimental antiphospholipid syndrome. 1059 Feb 57

Autoantibodies against prothrombin, including lupus anticoagulant antibodies (LAC), have been identified in patients with systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS). To identify the epitopes of LAC in patients with SLE and APS, we analyzed B cell epitopes of anti-prothrombin Abs. Prothrombin was purified from fresh plasma samples from healthy subjects, and fragmented by thrombin. Two fragments (prethrombin-1, 50 kDa, and fragment-1, 22 kDa) were separated and used for further experiments. The two fragments were coated on irradiated plate and the binding activities of sera from 13 patients with anti-prothrombin Abs (SLE, 7; APS, 4; SLE+APS, 2) were determined by using ELISA. The assay was conducted under the following conditions: use of irradiated plates, and TBS containing Tween-20. We detected two types of anti-prothrombin Abs. The first was anti-prethrombin-1 (n=5) while the other was Ab against fragment-1 (n=8). There were no patients with Abs that showed binding activities to both fragments. A higher proportion of patients with thrombosis were positive for anti-prethrombin-1 Abs (80%) than for anti-fragment-1 Abs (25%). Two patients with anti-prethrombin-1 Ab were positive for LAC and negative for anti-cardiolipin-beta2 glycoprotein I antibody (aCL-beta2GPI). Our results strongly support the notion that both prethrombin-1 and fragment-1 on prothrombin molecule are B cell epitopes.
Lupus 1999
PMID:Relationship between clinical features and binding domains of anti-prothrombin autoantibodies in patients with systemic lupus erythematosus and antiphospholipid syndrome. 1060 50

Recent scientific developments enable to better understand the strong heterogeneity of assay methods for phospholipid (PLP)-dependent antibodies, measured as lupus anticoagulant (LA) or as anti-PLP antibodies (APA). These latter are actually targeted at complexes of beta(2)-glycoprotein I (beta2GPI) and anionic PLP and also react with insolubilized beta2GPI alone in some patients. Although APA present little species specificity for beta2GPI, some of them bind preferentially to complexes of human beta2GPI and PLP. LAs are diagnosed with screening assays (dPT, dRVVT, KCT, APTT); their sensitivity is dependent on the concentration and type of PLPs used. They are either beta2GPI or prothrombin dependent. Based on the antibody-neutralizing capacity of PLP preparations (such as hexagonal phase phosphatidylethanolamine) or their bypassing activity, confirmatory assays enable to confirm LA. LAs and APAs bind to different epitopes on beta2GPI or its complexes with PLP. Major characteristics of APA assays are: the capture antigen (PLPs, beta2GPI source); its optimization and density on micro-ELISA plates; the efficacy of postcoating saturation; the animal serum used for saturation and diluent; the second antibody which must avoid nonspecific interactions; the calibrators proposed and their reference to international standards; the cutoff between the normal and the pathological ranges; the assay sensitivity and overall specificity for APAs. New optimized assays have been developed to meet these criteria. They are designed with PLP-coated plates, saturated first with immunoglobulin-free human serum as a source of beta2GPI, then with goat serum also used in diluent. The cutoff value is determined with at least 200 normal plasma samples (mean + 3 standard deviations or 99th percentiles) and plasma samples from patients without APAs. This approach offers both optimized specificity and sensitivity for testing APAs, along with a good standardization and it helps to measure the true APAs associated with pathology.
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PMID:Diagnostic approach of phospholipid-dependent antibodies. State-of-the art lecture. 1062 93


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