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)

Polyethylene glycol (PEG, 4%)-precipitated macromolecular IgG isolated from the sera of 20 patients with systemic lupus erythematosus (SLE) and 15 control subjects was analyzed for its IgG isotype concentration by single radial immunodiffusion. PEG precipitates from SLE sera had higher mean levels of IgG1, IgG2 and IgG3 and lower IgG4 than PEG precipitates isolated from normal sera although only the IgG2 levels were significantly different. Using an anti-complementary assay there was a significant correlation between the ability of parent sera to fix complement and the absolute levels of PEG precipitable IgG1, IgG2 and IgG3. These data suggest that the ability of immune complexes in the sera of patients with SLE to fix complement is dependent on their IgG subclass composition.
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PMID:IgG subclasses of PEG precipitable IgG in systemic lupus erythematosus sera. 271 25

Concentration of immune complexes (IC) in the serum of patients with various diseases (glomerulonephritis systemic lupus erythematosus--SLE, rheumatoid arthritis--RA and with positive antibodies to human immunodeficiency virus--HIV+) has been determined using two methods: PEG precipitation and laser nephelometry (NL) of binding to Latex = C1 12q complement components in aqueous media. The presence of antiimmunoglobulin antibodies, that is, rheumatoid factor (RF) and its eventual effect on the precision of measurement of IC using LN C1q method has been determined by LN-Latex RF method. The results have shown that the increased IC values obtained by one method can be within physiological levels if the other method was applied and vice versa. Depending on the group of examinees such negative correlation ranged from 33% to 64%. This is the result of already known limitations of the studied methods and confirms the necessity of simultaneous application of different methods for determination of IC concentration. Regardless of anticomplementary activity of serum rheumatoid factor its presence in the serum has not shown to have any effect on the precision of determination of IC concentration using IC by LN- C1q method.
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PMID:[The importance of using various methods in the determination of serum immune complex levels]. 280 Apr 18

Circulating immune complexes (IC) were assayed in 65 patients with systemic lupus erythematosus (SLE), 34 patients with rheumatoid arthritis (RA), 40 patients with progressive systemic sclerosis (PSS), 35 patients with chronic glomerulonephritis (GN) and 30 healthy controls. Immunoglobulin components of PEG-precipitated IC from 10 patients with SLE were also determined. Cryoglobulins isolated from 11 patients with SLE were assayed for their IC-like activity. The effect of corticosteroid treatment on IC levels were also studied in SLE patients with nephritis. IC levels significantly increased in all groups but those of SLE patients were the highest values. The SLE patients with nephritis had higher levels than those without renal involvement. IgG- d IgM- but no IgA-components were found in 100% and, 90%, respectively, of IC preparations. IC-like activity of cryoglobulins were found to correlate with disease severity and appeared to be characteristic of clinical manifestations. Corticosteroid therapy significantly decreased IC levels, however, related to the entire patient group, the mean of IC level was still higher than that of healthy controls. The degree of IC level decrease (as percentage), but not absolute values, appeared to be significant in assessing disease activity. The clinical significance of IC determination and IC activity of cryoglobulins are discussed.
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PMID:Clinical significance of circulating immune complex assay in patients with systemic lupus erythematosus. 281 55

By utilizing a monoclonal rheumatoid factor (mRF) and bovine conglutinin (K) in radioimmunoassays, ICs detected in sera of patients with lupus nephritis were partially characterized. The mRF-RIA detected high levels of ICs in 86.9% of patients with active SLE and in only 22.7% of patients with inactive disease. Positive association was observed with clinical scores and significant negative correlation was found with serum levels of C1q, C3 and C4. The mRF-reactive ICs were shown to be cryoprecipitable and analysis by gel filtration through Sephacryl S-300 disclosed a material eluting between IgM and IgG, being dissociated in acidic pH. On the other hand, no association could be demonstrated between levels of ICs detected by K-RIA and clinical activity. Positivity in this assay was only 8.7% and 31.8% for active and inactive groups. Differently from the ICs detected by mRF-RIA, the K-reactive material was not precipitated by 3.5% PEG, nor by centrifugation in the cold, and EDTA did not reduce the binding of IgG to K in positive sera. The reactive IgG in Sephacryl S-300 chromatography eluted in the same position as monomeric IgG both in neutral and dissociating conditions. No C3 could be detected in ICs reactive in both assays.
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PMID:Characterization of circulating immune complexes detected by monoclonal rheumatoid factor and conglutinin radioimmunoassays in SLE nephritis. 325 Oct 47

Antibodies to dsDNA differ in their avidity towards the antigen. The electrostatic interaction between DNA and anti-DNA is sensitive to increases in pH and/or ionic strength and therefore, elution studies employing either of these permit discrimination between anti-dsDNA populations that differ in avidity. Another way to determine anti-dsDNA avidity is the calculation of Farr/PEG ratios. These are obtained by division of the amount of anti-DNA measured with the Farr assay (which does not detect low avidity anti-dsDNA) by the amount measured with the PEG assay (which does detect low avidity anti-dsDNA). With these separate approaches, we compared the sera of 17 SLE patients with nephritis with the sera of 17 patients with central nervous system (CNS) involvement. Farr/PEG ratios and sensitivity to high pH elution of anti-dsDNA in the sera of these patients both permitted discrimination between the two groups of patients. The anti-dsDNA of patients with nephritis was found to have a significantly higher avidity towards DNA than anti-dsDNA of patients with cerebral disease. We also observed a significant correlation between Farr/PEG ratios and the salt lability of anti-dsDNA.
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PMID:Dissociation studies of DNA/anti-DNA complexes in relation to anti-DNA avidity. 328 12

HIV-seropositive homosexuals, narcotic addicts and hemophiliacs develop a new syndrome of immunologic thrombocytopenic purpura (ITP) which is clinically indistinguishable from classic autoimmune thrombocytopenic purpura (ATP) with respect to increased megakaryocytes in the bone marrow, peripheral destruction of antibody-coated platelets, negative serology for SLE, response to treatment with prednisone and/or splenectomy. Eleven of 79 homosexual patients have developed AIDS 2 to 43 months after the diagnosis of ITP (mean, 22 months). The mechanism of the ITP appears to be different in homosexuals and narcotic addicts when compared to classic ATP. Homosexuals and narcotic addicts have markedly elevated platelet-bound IgG and C3C4 (2.5-4-fold ATP levels), PEG-precipitable circulating immune complexes and anti-F(ab')2 antibodies (absent in ATP). There is no inverse relationship between platelet-bound IgG and platelet count and platelet antibody is usually not elutable from washed platelets as is the case with classic ATP. Homosexual patients do not have 7S platelet antibody in their sera as do classic ATP patients, but appear to have immune complex deposition on their platelets, possibly due to the presence of anti-F(ab')2 antibodies. Narcotic addict patients do have detectable 7S platelet antibody but also appear to have immune complex deposition on their platelets, possibly due to anti-F(ab')2 antibodies. The anti-F(ab')2 antibodies are of the IgG class. They react with autologous, homologous patient and healthy control F(ab')2 fragments. Some anti-F(ab')2 antibodies have broad reactivity, others are more limited. It is postulated that some of the anti-F(ab')2 antibodies may be responsible for the thrombocytopenia.
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PMID:Immunologic thrombocytopenic purpura in patients at risk for AIDS. 333 92

Three different tests which are based on different principles were used for the detection of soluble immune complexes (IC): (i) a PEG precipitation test, which is based on the solubility characteristics of IC; (ii) a solid-phase C1q binding assay, which is based on the complement binding property of IC, and uses peroxidase-linked anti-human IgG to detect the bound IC (C1q-ELISA); and (iii) the indirect granulocyte phagocytosis test (IGPT) which is based on the Fc R- and possibly the C3 R-binding of IC. Using heat-aggregated IgG (A-IgG) as a model for soluble IC all three tests showed a linear relation with the amount of A-IgG. The C1q-ELISA and the IGPT had a detection limit of less than 1 microgram/ml while the PEG test only detected quantities of more than 10 micrograms/ml. However, when using artificially produced soluble IC, which were prepared from human antibodies (ab) of different specificities and their respective antigens (ag) i.e., (i) tetanus toxoid, (ii) Helix pomatia hemocyanin (HPH), and (iii) dsDNA, and which consisted of the two components in a wide range of ag/ab ratios, distinct results were obtained with the three tests. Thus demonstrating that results obtained with A-IgG as a model for soluble IC can not simply be extrapolated to the behavior of real complexes in IC detection assays. No matter which ag was used, the composition of the IC, i.e., the ratio in which ag and ab were present, appeared to be the crucial factor for detectability in the different tests. The C1q-ELISA can detect IC over a wide range of ag/ab ratios, while it is particularly sensitive for IC formed in slight ag excess. The IGPT in contrast primarily detects, and is highly sensitive for, IC formed in ab excess. The PEG test appears to detect IC with freshly bound complement only. Another interesting finding has to be mentioned here: when increasing amounts of dsDNA were added to a SLE serum containing anti-DNA ab, the IC that had been detectable in the native serum with the IGPT completely disappeared, thus demonstrating that these complexes did consist of DNA and anti-DNA.
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PMID:Characterization of the soluble immune complexes that are detected by three different techniques. 348 41

Patients with rheumatoid arthritis, systemic lupus erythematosus, and spondylitis ancylopoetica were examined, along with healthy controls, for C3d plasma levels, circulating immune complexes, C3 serum levels, and CRP. Immune complexes were determined using a Clq binding assay, a 2.75% PEG precipitation technique, including the analysis of IgG and C3, and a new laser nephelometric latex test. C3d plasma levels were significantly (P less than 1%) elevated in all groups of patients as compared to controls. With regard to the demonstration of circulating immune complexes, the PEG precipitation method discriminated best between patients and the control population. It was not possible to differentiate between the different disease entities with neither C3d serum levels or immune complexes. Concerning the assessment of disease activity, none of the evaluated parameters alone appears to be of clinical relevance. The individual application of more than one immune complex assay in combination with the measurement of C3d serum levels must be recommended if disease activity is to be assessed.
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PMID:Evaluation of plasma C3d and immune complex determinations in the assessment of disease activity of patients with rheumatoid arthritis, systemic lupus erythematosus, and spondylitis ancylopoetica. 389 37

An assay to detect circulating immune complexes is described and exemplified with serum from SLE and RA patients. The method is based on selective precipitation of immune complexes with PEG followed by a specific ELISA assay to detect the immunoglobulins present in the precipitate. The immunoglobulins of the precipitate were then monitored by their capacity to bind protein A and dDNA. With the PEG-protein A-ELISA procedure immune complexes were detected in 46% of the sera from SLE patients compared with 68% when using the PEG-DNA-ELISA.
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PMID:Detection of circulating immune complexes by PEG precipitation combined with ELISA. 397

Circulating immune complexes were determined in rheumatoid arthritis and systemic lupus erythematosus using a semiautomated PEG-precipitation laser-nephelometer technique. Immunoglobulins IgA, IgG and IgM as well as complement proteins C3c and C4 were quantitatively determined in 2.75% PEG-precipitates. The PEG-precipitates obtained from the sera of healthy controls, SLE patients, and RA subjects displayed different protein patterns. In RA sera a significant elevation of all investigated proteins was found. In SLE sera, a significant increase of IgG, IgA, IgM, and C3 was found, whereas C4 was significantly reduced as compared to the controls. Typical values for a calculated IgG/C4 ratio in circulating immune complexes were obtained for RA and SLE. In RA this ratio remained unchanged in different activity stages and was found in seropositive as well as in seronegative sera. Thus circulating immune complexes from SLE and RA sera differ with respect to the degree of complement-dependent solubilization.
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PMID:[Demonstration and differentiation of circulating immune complexes in chronic inflammatory rheumatic diseases using a semiautomated PEG-precipitation laser nephelometer test]. 405 Jan 41


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