Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Established solid phase assays for anticardiolipin antibodies (aCL) are often characterized by high levels of nonspecific binding. As a result, only very high levels of aCL have been reported to be associated with a variety of clinical conditions including systemic lupus erythematosus (SLE), recurrent intravascular thrombosis and unexplained recurrent fetal loss. We have developed an ELISA replacing direct evaporation of soluble cardiolipin with cardiolipin micelles in physiological saline as the antigen binding step in the assay. Levels of IgG aCL were detected in various sera at dilutions of 1/100 to 1/3200, showing improved assay sensitivity. Assay specificity was determined using double stranded DNA and ovalbumin as irrelevant binding antigens and no crossreactivity was found. The controversial use of Tween 20 in the assay was investigated and results showed it decreases nonspecific binding without interfering in antibody detection. This assay has enabled us to identify differences in the prevalence and level of aCL antibodies in sera from healthy nonpregnant controls (0/25 positive), healthy pregnant controls (5/47 positive for IgG and 8/47 positive for IgM) and from women with unexplained recurrent fetal loss (16/62 and 14/62 positive, respectively). We support the observation that aCL are not normally distributed, and therefore nonparametric methods of statistical analysis are necessary to determine population prevalence. We confirm that aCL IgM are a relatively nonspecific finding, and extreme caution must be used in basing any clinical decisions on the presence of this antibody alone.
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PMID:Clinical utility and specificity of anticardiolipin antibodies. 179 24

Serum from patients with systemic lupus erythematosus (SLE) and hybridoma culture fluids derived from the fusion of SLE lymphocytes contain antibodies to native DNA (nDNA) and denatured DNA (dDNA). A rapid, efficient solid phase radioimmunoassay (RIA) was developed to screen for minute quantities of these autoantibodies. The RIA, which utilized polystyrene tubes, required the addition of 0.1% bovine serum albumin and 0.01% Tween 20 detergent to decrease nonspecific immunoglobulin binding. Pretreatment of the polystyrene tubes with poly-L-lysine (PLL) prior to coating with DNA increased the binding of radiolabeled nDNA from 15 to 46% and of dDNA from 17 to 63%. This PLL precoating step resulted in a 3-fold increase in the specificity of the assay for nDNA but was not advantageous for dDNA. The method described is sensitive, specific, and can be applied to the screening of microgram quantities of anti-DNA autoantibodies in serum and hybridoma culture fluids.
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PMID:Sensitive solid phase radioimmunoassay for the detection of anti-DNA autoantibodies. 404 48

We investigated whether or not the use of Tween 20 could help to distinguish beta 2-glycoprotein I (GPI) independent anticardiolipin antibody (aCL) (syphilis-type aCL) from GPI-dependent aCL (SLE-type aCL) in a GPI-dependent/independent aCL ELISA. aCL was positive in all 16 SLE patients and all 15 syphilis patients, who were positive for aCL in the standard ELISA, in the GPI-independent ELISA with Tween 20. GPI-dependent aCL was detected in 12/16 SLE patients by the GPI-dependent ELISA with Tween 20. aCL was not detected in any of the syphilis patients by GPI-dependent ELISAs. On the basis of these results, we recommend that Tween 20 should be used in ELISAs to distinguish GPI-dependent aCL from GPI-independent aCL.
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PMID:Distinguishing beta 2-glycoprotein I dependent (systemic lupus erythematosus type) and independent (syphilis type) anticardiolipin antibody with Tween 20. 794

Some lupus anticoagulants (LA) have been shown to be directed against phospholipid-bound prothrombin. While developing an ELISA to detect anti-prothrombin autoantibodies in patient serum or plasma, no or very low signal was observed using human prothrombin immobilized on plain polystyrene plates. In contrast, the same LA-positive samples bound specifically to prothrombin coated on gamma-irradiated plates, depending on the radiation dose, in the absence of added calcium and phospholipid. Optimization of the assay required the addition of 0.1% Tween 20 to the buffers. Antibody specificity for immobilized prothrombin was ascertained by competition using liposome-bound prothrombin, since fluid-phase prothrombin competed poorly. Seventy-seven of 139 patients (55.4%) with LA related to a variety of underlying diseases possessed anti-prothrombin antibodies (27 IgG, 35 IgM and 15 both isotypes), either isolated or more often associated with anti-beta 2 glycoprotein I (beta 2GPI) antibodies. These included 67-71% of the patients with systemic lupus erythematosus and related disorders, primary antiphospholipid antibody syndrome or drug-induced LA (autoimmune groups), but only 19-20% of those with infection or malignancy (p < 0.001). As previously shown for anti-beta 2GPI antibodies, IgG2 was the predominant IgG subclass reactive with prothrombin. Thus, autoimmune patients with LA have a high incidence of antibodies to beta 2GPI and prothrombin, the binding of which could similarly require high antigen density and/or exposure of cryptic epitopes resulting from protein interaction with an irradiated (i.e. more anionic) polystyrene surface.
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PMID:Development of an ELISA for autoantibodies to prothrombin showing their prevalence in patients with lupus anticoagulants. 856 Apr 23

Antiphospholipid antibodies (aPL) react with negatively charged phospholipids, which may often be complexed with a protein cofactor such as beta2 glycoprotein (beta2GPI) and prothrombin. Cofactor requirements may be assessed by measuring antibodies to beta2GPI or by adding Tween 20 to some reagents in the assays for aPL (anticardiolipin and antiphosphatidyIserine). We have measured anticardiolipin antibodies (aCL), antiphosphatidylserine antibodies (aPS), and anti beta2 glycoprotein antibodies (abeta2GPI) in the serum of 10 normal subjects, 20 patients with systemic autoimmune diseases (SAD) diagnosed as having systemic lupus erythematosus (SLE) or antiphospholipid syndrome (APS), and 12 patients with HIV infection. Adding Tween 20 to aPS, the assay couldn't differentiate protein cofactor dependent from independent antibodies, but this can be done by measuring abeta2GPI (P= 0.0008). There was a significant correlation between aCL and a(beta)2GPI in the control group and in the patients with SAD, but not in the HIV-positive (HIV+) patients. After excluding the HIV+ patients, the best Spearman correlation was obtained between a(beta)2GPI and aCL (0.64, P< 0.0005). In 3 out of 7 patients with positive a(beta)2GPI and in 5 out of 6 patients with moderate or high positive aCL of the group of SAD, there was a history of venous thrombosis. The presence of moderate or high values of aCL either alone or together with a(beta)2GPI was significantly associated with a history of venous thrombosis (P < 0.05). Moderate or high aCL concentrations and their association with a(beta)2GPI seems to be useful for the assessment of the risk of venous thrombosis in unselected patients with SLE or APS.
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PMID:Antiphosphatidylserine antibodies in patients with autoimmune diseases and HIV-infected patients: effects of Tween 20 and relationship with antibodies to beta2-glycoprotein I. 1010 33

Autoantibodies directed against intracellular antigens can be detected by immunoblotting (IB). Due to its high sensitivity this technique has many advantages, but it can give misleading results when the specific bands are weak or blurred against the background staining. To decrease background staining, non-ionic detergents (Tween 20, Triton X-100, Nonidet P-40) are generally used as blocking agents. Moreover, these agents appear to have a renaturating action towards proteins and antigens. Tween 20 has a more pronounced renaturating effect on proteins than other detergents and thereby improves antigen-antibody binding. To evaluate the effect of Tween 20 on specific autoantibody detection by IB, we tested the sera of 162 patients with connective tissue diseases (CTDs) by adding this detergent at certain steps of the IB assay. We found that the use of Tween 20 in the IB procedure significantly improved the binding of autoantibodies to Jo-1, Scl70, (U1)RNP 68 kDa and C, Sm B/B' and D. Moreover, it increased the sensitivity for the detection of anti-Sm D peptide in systemic lupus erythematosus (SLE) sera with no decrease in specificity. In contrast, the addition of Tween 20 significantly decreased the binding of autoantibodies specific for ribosomal P proteins, La/SSB, Ro/SSA, but not the overall sensitivity and specificity of the method. We conclude that the addition of Tween 20 to standard IB is advantageous for anti-nuclear antigen antibody detection and improves the sensitivity of the method in revealing anti-Sm-positive sera in SLE. However, Tween 20 is not recommended for the detection of anti-cytoplasmic antibodies.
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PMID:The use of Tween 20 in immunoblotting assays for the detection of autoantibodies in connective tissue diseases. 1082 42

Calreticulin has been reported to be an autoantigen in various autoimmune connective tissue diseases and in coeliac disease. Previous studies have used incubation buffers with low salt and low detergent concentrations (low stringency conditions) with serum albumin or other proteins as a blocking agent. Using these conditions we found a relatively high level of non-specific binding in many sera. Antibodies to proteins that are used as blocking reagents in ELISA (bovine serum albumin (BSA), ovalbumin, skimmed milk powder) are frequently present in sera, and these may cause false-positive results. Moreover, the low isoelectric point of calreticulin and its chaperone properties may give rise to false-positive results under low stringency conditions. We report that the use of a simple buffer without protein (50 mM Tris, pH 7.5, 1% Tween 20, 0.3 M NaCl) removes most of the problems with unwanted binding (high stringency conditions). Using the high stringency conditions, we screened sera from 107 patients with systemic lupus erythematosus, sera from patients with other systemic autoimmune diseases and from children with coeliac disease for the presence of high-affinity calreticulin autoantibodies by immunoblotting and ELISA. None of the sera contained high-affinity calreticulin antibodies. It is concluded that calreticulin is not a common autoantigen in patients with autoimmune connective tissue diseases or coeliac disease.
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PMID:Absence of high-affinity calreticulin autoantibodies in patients with systemic rheumatic diseases and coeliac disease. 1608 63