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)

The occurrence and composition of complexed beta2-microglobulin (beta2m) in sera and synovial fluids of rheumatoid arthritis and systemic lupus erythematosus patients and control persons was investigated. Beta2m-containing complexes were detected in immune complex (IC)-enriched fractions isolated by precipitation with 3% polyethylene glycol 6000, in the macromolecular peaks after Sephadex G-200 gel filtration, and in IC desorbed from solid-phase Clq. Beta2m complexes were demonstrated also after precipitation of redissolved PEG-insoluble material by anti-human beta2m serum or isolation of the complexes by use of Sephadex-anti-beta2m. IgG was co-isolated with beta2m on Sephadex-anti-beta2m and free beta2m inhibited the binding of IgG to Sephadex anti-beta2m, indicating that IgG was present in the complexed beta2m. Analysis by SDS-polyacrylamide gradient electrophoresis under reducing conditions indicated that the purified beta2m complexes contained IgG and beta2m.
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PMID:Beta2-microglobulin-containing IgG complexes in sera and synovial fluids of rheumatoid arthritis and systemic lupus erythematosus patients. 616 72

In 2 radioimmunoassays in use to detect antibodies to dsDNA, the Farr assay and the PEG assay, we observed inhibitory effects of normal human serum (NHS) on the DNA binding by SLE sera. This was found to be due by the fact that, during incubation at 37 degrees C, CO2, introduced in the incubation mixture by the serum, evaporates from the mixture. This results in increase in pH to values well above pH 8.0, which in turn leads to a decreased DNA binding by antibody. When SLE sera are tested at low dilution, this phenomenon may lead to false negative results. Proper pH control, by the use of buffers with a greater buffering capacity than PBS, completely prevented the observed inhibitory effects. However, under these conditions NHS bound significant amounts of DNA in both assays. The non-specific DNA binding by NHS was found to be heat-stable, but could be eliminated either by aerosil treatment of the sera or by addition of dextran sulphate to the incubation mixture. Lipoproteins and, to a lesser extent, the complement component C1q appear responsible for this non-specific binding. To avoid false negative results with SLE sera as well as non-specific binding by NHS, we propose the use of stronger buffers in combination with added dextran sulphate to the incubation mixture in both the Farr assay and the PEG assay.
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PMID:Influence of pH on the detection of low- and high-avidity anti-dsDNA. 618 61

The effect of immune complexes (IC) isolated from systemic lupus erythematosus (SLE) sera with polyethylene glycol and gel filtration on the chemotaxis and Fc receptor function of healthy monocytes was examined. Even at a low protein concentration (1 microgram/ml = 1 mg/l) ICs inhibit monocyte chemotaxis. ICs from patients with SLE nephritis are more inhibitory than ICs from patients without renal disease. The inhibitory effects of ICs on monocyte chemotaxis and Fc receptor activity are similar, suggesting a relationship between the chemotactic and Fc receptor function of monocytes. Analysis of the ICs by enzyme-linked immunoassay showed no correlation between the quantity of IgG, C3, and anti-DNA in the IC samples and their effects on monocyte function.
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PMID:Effects of immune complexes from SLE patients on human monocyte locomotion and Fc receptor function. 633 50

Lymphocytotoxic activity is known to better occur at low temperatures and to be relatively enriched in cryoglobulins. As the cold insoluble globulin, Fibronectin, is a main component of cryoglobulins, experiments were carried out to find out whether Fibronectin was involved in the mechanism of cytotoxicity or not. No direct or indirect (complement-mediated) effects were seen. A significant association was observed between lymphocytotoxic activity and circulating immune complexes and between Fibronectin positivity and cytotoxicity in PEG-precipitates of sera from three groups of patients affected with SLE, RA and Ps.A. respectively. As Fibronectin is a cryoprecipitagogue protein, possible implications of these findings are discussed.
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PMID:Cold insoluble globulin: relationship with lymphocytotoxins in autoimmune diseases. 633 64

A C1q-ELISA for the detection of immune complexes is described in which the sensitivity was increased by the addition of polyethylene glycol (PEG). Although the ELISA without PEG adequately detected immune complexes in sera from patients with autoimmune disorders, when sera from patients with filariasis were tested, there was little correlation between values obtained with ELISA and the 125I-C1q binding assays. The addition of PEG to the filariasis sera before reacting the bound complexes to the enzyme conjugated anti-IgG increased the sensitivity to allow detection of immune complexes in those sera. This could be done without adversely affecting the reaction with normal sera or sera from patients with systemic lupus erythematosus. The solid phase C1q-ELISA with the PEG modification can be used for the detection of immune complexes in filariasis and should be adaptable for use with sera from other parasitic infections.
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PMID:A C1Q enzyme-linked immunosorbent assay (ELISA) using polyethylene glycol for immune complexes. 634 May 43

A method for rapid determination of average masses and concentrations of circulating immune complexes in human sera is suggested. It is based on the dissimilarity in solubilities of immune complexes with different masses in the presence of polyethyleneglycol. Light-scattering intensities are measured by a laser nephelometer after adding to the serum of PEG in two different concentrations. The experimental values of the average masses and concentrations are calculated using calibration curves. The calibration curves are plotted for model immune complexes with different average masses obtained by heat-aggregation of IgG at various concentrations. This technique has been employed for determination of the average masses and concentrations of circulating immune complexes in 17 patients suffering from systemic lupus erythematosus and in 8 control individuals.
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PMID:A method for quantitative determination of average masses and concentrations of circulating immune complexes in human sera. 634 Dec 14

Sera from 86 individuals were tested for circulating immune complexes by the polyethylene glycol precipitation method and a Raji cell enzyme immunoassay (Raji-ELISA). These included normal nonpregnant control subjects, nonpregnant patients with autoimmune diseases, healthy women in the second and third trimesters of pregnancy, patients with preeclampsia, and women with pregnancies complicated by preexisting autoimmune diseases. Diseases such as systemic lupus erythematosus and rheumatoid arthritis were associated with increased levels of immune complexes in both pregnant and nonpregnant individuals. Circulating immune complexes were not observed in normal pregnancies or in preeclampsia. Although pregnancy itself is not an immune complex-associated state, the presence of immune complexes in autoimmune diseases may explain some of the complications observed during pregnancy in these patients.
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PMID:Circulating immune complexes in pregnancy, preeclampsia, and autoimmune diseases: evaluation of Raji cell enzyme-linked immunosorbent assay and polyethylene glycol precipitation methods. 635 22

Repeated determinations of beta 2-microglobulin (beta 2m) and beta 2-microglobulin binding activity (beta 2m ba) in serum were performed during a follow-up of 23 patients with SLE. beta 2m was determined by a radioimmunoassay. Individual mean values were raised in 65% of the patients. The mean value for all patients, 2.9 mg/l, was significantly higher than that of the controls. The beta 2m concentrations parallelled the clinical disease activity in several cases with different disease manifestations. The beta 2m ba was determined by precipitation of 125I-labelled beta 2m with polyethylene glycol. Increased beta 2m ba was found in 26% of the SLE patients with the 90th percentile in 40 healthy subjects being taken as the upper normal limit. There were, however, no significant differences between the mean values for beta 2m ba in the patients and the controls. Patients with systemic lupus erythematosus (SLE), suffering exacerbation of their disease, had a higher mean beta 2m ba than those with less active disease. Variations of the serum beta 2m ba occurred especially in patients with active disease but did not seem to reflect the clinical course. The beta 2m ba was recovered in the IgG peak when SLE serum was subjected to gel chromatography on Sephadex G-200.
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PMID:Beta 2-microglobulin and its binding activity in serum from patients with SLE. 637 Jan 53

A comparative study of four nonspecific screening techniques (direct nephelometry, PEG-C4, PEG-IgG, and radiolabeled Clq binding) for immune complexes (IC) and of a technique specific for the detection of insulin-anti-insulin IC was undertaken in four groups of patients with diagnosis of infectious endocarditis, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and diabetes. The highest frequency of positive results was given by the PEG-IgG test in RA, the Clq-binding test in SLE, the insulin-anti-insulin IC screening test in diabetes, and the PEG-IgG and Clq-binding tests in infectious endocarditis. Of the four nonspecific tests, the PEG-C4 assay appeared to be the least discriminative, since it failed to show significant differences between any group of patients and the group of controls. Direct nephelometry, PEG-IgG, and radiolabeled Clq binding gave consistently higher results in RA than in other diseases, and in this disease the rates of agreement between these tests were highly significant. Significant agreements between the rates of positivity of Clq binding and PEG-IgG tests were seen in all groups of patients studied. Spearman's analysis of rank showed the best correlations among tests based on similar principles (ie, PEG precipitation), and also a strong correlation between Clq binding and the PEG-IgG test in RA. The PEG-IgG test appears to be a reliable IC screening test for general use with the advantage of not involving radioisotopes. In regard to antigen-specific tests, although their specificity and sensitivity may be high, their results may show no correlation with nonspecific screening tests nor with the presence or absence of clinical or laboratory abnormalities suggestive of IC deposition, as exemplified by the insulin-anti-insulin IC screening test in diabetic patients.
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PMID:Statistical analysis of five immune complex screening assays: patterns of detection in patients with rheumatoid arthritis, systemic lupus erythematosus, infectious endocarditis, and diabetes mellitus. 638 65

A method, measuring the activity of circulating immune complexes, based on C3 conversion of fresh human plasma by means of 3 per cent PEG precipitable immune complex-rich sera fractions is reported. Sera of patients suffering from autoimmune diseases of the connective tissue as well as of healthy controls were investigated. In case of standardised protein concentration of immune complexes, significantly low C3 conversion frequency of the isolated fractions has been observed in the control group as compared to the examined patients (rheumatoid arthritis with and without extraarticular manifestations, or juvenile chronic arthritis, or systemic lupus erythematosus). PEG fractions of RA with extraarticular manifestations induced the significantly highest C3 splitting. It is assumed that immune complexes will show a distinct interaction with the complement system also in vivo, and are therefore directly implicated in the systemic course of the disease process.
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PMID:[Functional analysis of immune complex-rich serum fractions in autoimmune diseases by in vitro C3 activation of fresh blood]. 645 23


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