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)

We examined whether antibodies (present in sera from patients with Graves' disease) might be directed against a connective tissue cellular component of the anatomical regions affected in the peripheral manifestations of that disease. Accordingly, we performed immunoblot analyses of cultured retroocular and pretibial fibroblasts. Retroocular connective tissue was obtained during orbital decompression surgery (n = 7) and at autopsy from normal individuals (n = 2). Pretibial skin biopsies were obtained from patients with pretibial dermopathy (n = 3) and at autopsy (n = 2). In addition, biopsies from other regions [extraocular muscle (n = 6), thyroid (n = 2), and abdominal skin (n = 3)] were also collected at surgery or autopsy. Serum samples were obtained from patients with severe Graves' ophthalmopathy (n = 31), hyperthyroid Graves' disease without overt ophthalmopathy (n = 13), nodular thyroid disease (n = 7), Hashimoto's thyroiditis (n = 7), rheumatoid arthritis (n = 5), and systemic lupus erythematosus (n = 3) and from normal individuals (n = 33). Electrophoresed fibroblast proteins were immunoblotted with 1:100 dilutions of sera using an antihuman immunoglobulin G-alkaline phosphatase conjugate. Antibodies against a 23kDa fibroblast protein were present in the sera from 24 of 44 (56%) of patients with Graves' disease with or without ophthalmopathy, 0 of 7 nodular thyroid disease, 0 of 7 Hashimoto's thyroiditis, 0 of 5 rheumatoid arthritis, 0 of 3 systemic lupus erythematosus, and 5 of 33 (15%) normal subjects. Significant differences in the observed frequency of antibodies existed between the Graves' disease group and the normal control group (P less than 0.01) or those patients with the other conditions (P less than 0.01). This 23kDa antigen was apparent in fibroblasts derived from individuals with Graves' disease as well as normal individuals and was present in fibroblasts from all anatomical sites studied. It was the sole protein uniquely recognized by sera from patients with Graves' disease. However, this serum reactivity did not appear to be related to the presence of clinically overt ophthalmopathy or pretibial dermopathy. Subcellular localization studies disclosed that the antigen was present in the supernatant but not the pellet resulting from a 100,000 x g centrifugation of whole cell sonicates. Antibodies against a 23kDa fibroblast protein are present in the majority of sera from patients with Graves' disease and rarely in sera from either normal individuals or those with other thyroid disorders or autoimmune diseases. Our results suggest the possibility that antibodies directed against this fibroblast antigen may be related to the developm
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PMID:Presence of antibodies in the sera of patients with Graves' disease recognizing a 23 kilodalton fibroblast protein. 276 Jan 73

A quantitative assay for C4-containing immune complexes (IC) by a solid phase anti-C4 micro ELISA is described. It is based upon the use of an affinity purified chicken anti-human C4 antibody to capture the immune complex, and protein A-alkaline phosphatase for detection. The chicken antibody was chosen as capture antibody because it does not react with rheumatoid factor, does not activate the human complement system and is not detected by anti-mammalian IgG antibodies or protein A. Increased levels of C4 containing circulating immune complexes (CIC) were detected in sera from patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and lung cancer, when compared with normal sera. Normal levels of C4 containing immune complexes were found in sera from patients with Bell's palsy.
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PMID:Quantification of circulating immune complexes by chicken anti-C4 micro ELISA. 315 Jul 66

A solid-phase enzyme-linked immunoabsorbent assay (ELISA) is described for the detection and quantitation of anticardiolipin antibodies (ACAs) IgG and IgM in sera. In these assays, non-specific binding was controlled by using antigen-negative wells for all serum dilutions tested. Quadruplicate 100-microliters serum samples diluted 1:20 for ACA-IgG and 1:40 for ACA-IgM were incubated for two hours, after which alkaline phosphatase-conjugated antihuman IgG or IgM was added. A standard serum was used on each plate to provide reproducibility of the assay. Upper limits of normal for ACA-IgG and IgM were established by testing 161 sera from normal persons. Sixty-one selected patients with SLE were tested; and, from these results, categories of positivity were defined from negative to 4+. All screen-positive sera (greater than or equal to 1+) were assayed in a quantitative ELISA assay for ACAs, using multiple dilutions of the unknowns. These data were fit on a standard curve generated with dilutions of a reference serum on each plate using a computerized data reduction system based on the 2 Plus 2 model. The standard curves were compared with the international standards for IgG and IgM anticardiolipin. The ability to quantitate ACA concentrations allows better definition of positive sera, as well as the opportunity to accurately evaluate and follow this antibody in a variety of patient groups.
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PMID:A solid phase enzyme immunoassay (ELISA) for the detection and quantitation of anticardiolipin antibody. 317 75

We describe an ELISA for assessment of complement function based on the capacity of serum to support fixation of complement components to solid phase immune complexes (IC). Microplates were coated with aggregated bovine serum albumin (BSA) followed by rabbit anti-BSA IgG. The solid phase IC were reacted with human serum. The uptake of C3b, C4b and properdin was measured using biotinylated F(ab)2 antibodies to each of the proteins, avidin alkaline phosphatase, and paranitrophenyl phosphate. Serial samples obtained from 15 patients with systemic lupus erythematosus were investigated. Out of 72 sera, 24 showed a reduced capacity to support incorporation of C4b into solid phase IC. Thirty-one of the sera showed low C3b binding and 59 of the sera a reduced uptake of properdin. The incorporation into solid phase IC of C3b and C4b as well as of C3b and properdin were closely correlated at high disease activity. In general, patients with severe disease manifestations showed low values in the uptake assays. Judging from the results obtained by analysis of serial samples, the uptake of C3b, C4b and properdin, complement mediated solubilization of fluid phase IC and the concentrations of C1q binding IC were useful indicators of disease activity in the patients. The concentrations of circulating C4, C3 and properdin varied less consistently according to disease activity. The concentrations of serum properdin were never found to be low, which was in contrast to the finding of reduced properdin uptake by solid phase IC in most of the samples.
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PMID:Complement fixation by solid phase immune complexes. Reduced capacity in SLE sera. 326 27

Self recently described a substrate system for alkaline phosphatase (AP)-dependent ELISAs which markedly increased sensitivity, compared to using p-nitrophenyl phosphate. This increase is achieved by having AP, the primary enzyme, produce an activator for a secondary enzyme-substrate system, within which marked amplification occurs. We adapted this technique to study antibodies to casein, bovine serum albumin, ovalbumin, and cardiolipin in the sera of patients with systemic lupus erythematosus (SLE) and normal individuals. The new substrate system yielded titres 30-50-fold higher than those with p-nitrophenyl phosphate (Sigma 104, p-NPP). In addition, when used in a solid-phase C1q binding assay we were able to use a 1 : 100,000 dilution of AP-conjugated anti-human IgG with the amplified substrate, compared to the 1 : 1000 dilution needed with p-NPP. This system is extremely valuable because of its flexibility. It can either be very sparing of limited samples, or if the added sensitivity is not needed, 100-fold less AP conjugate may be used. Thus rare or expensive conjugates can be significantly conserved.
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PMID:A substrate amplification system for enzyme-linked immunoassays. Demonstration of its general applicability to ELISA systems for detecting antibodies and immune complexes. 349 82

We describe the development of a simple and highly sensitive double antibody sandwich enzyme-linked immunosorbent assay (ELISA) for measuring IgG and IgM anticardiolipin antibodies (ACA). Microtitre plates were coated with cardiolipin at a concentration of 45 micrograms/ml by evaporation under nitrogen. Non-specific binding of diluted sera was eliminated by blocking of plates with 10% fetal calf serum in phosphate buffered saline (PBS/FCS) for 2 h. Then sera (100 microliters) at a dilution of 1:100 were incubated in the wells for 1 h. Affinity purified goat anti-human IgG or IgM (100 microliters) at a concentration of 1 microgram/ml was subsequently added and allowed to incubate for 1 h; detection of ACA was achieved using an alkaline phosphatase conjugated rabbit anti-goat IgG reagent by reading the colorimetric yield at 405 nm after incubation with substrate. Reference serum pools were established to study reproducibility of the assay throughout its sensitivity range, and Standard curves were established. The quantitative normal range was 0-9.0 Anticardiolipin ELISA Units (AEU) for IgG and 0-8.0 (AEU) for IgM-ACA. A strong correlation was found between the ELISA and radioimmunoassay methods for measuring ACA of both IgG and IgM classes. Results from 65 patients with systemic lupus erythematosus (SLE) and 45 patients with seropositive rheumatoid arthritis are also reported. The advantages of the ELISA method for quantitative determination of ACA levels, should make it a useful and reliable method for clinical and experimental monitoring of patients with SLE and associated autoimmune disorders.
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PMID:Measurement of anti-cardiolipin antibodies by an enzyme-linked immunosorbent assay (ELISA): standardization and quantitation of results. 408 54

Surface-bound platelet IgG and IgM were measured by an enzyme-linked immunosorbent assay (ELISA) using washed platelets and commercially available alkaline phosphatase anti-human immunoglobulins (Fc-specific). With this technique platelets from normal donors had small amounts of platelet-bound IgG ranging from 0.00 to 0.16 A405 (absorbance at 405 nm wavelength) (10(7) platelets)-1 (0 to 124 ng) and of platelet-bound IgM ranging from 0.00 to 0.05 A405 (10(7) platelets)-1. Eight out of 10 (80%) thrombocytopenic patients with idiopathic autoimmune thrombocytopenic purpura (IATP) had values of both IgG and IgM exceeding the normal range. In addition, one patient (8%) had platelet-bound IgM only. An inverse relationship was demonstrated in patients with IATP between the blood platelet count and the amount of both IgG and IgM. Increased values were also demonstrated in patients with SLE and patients with monoclonal hypergammaglobulinaemia. The direct ELISA is a useful and reproducible technique for platelet-bound IgG and IgM, which requires standard laboratory equipment only.
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PMID:Enzyme-linked immunosorbent assay (ELISA) for direct quantification of surface-bound platelet immunoglobulins. 622 25

A microplate-adapted enzyme linked immunosorbent assay (ELISA) for detection of C1q-binding immune complexes (IC) and aggregated IgG (delta IgG) is described. Purified human C1q was adsorbed to the wells of flat-bottomed microtiter plates and EDTA-treated serum samples were subsequently introduced. Bound IC was measured by use of alkaline phosphatase-labelled Protein A followed by the substrate para-nitro-phenyl-phosphate. A dose response was found for both delta IgG and BSA anti-BSA complexes, while variations in the concentration of monomer IgG did not affect the optical density. Elevated levels of IC were found in the majority of sera from patients with rheumatoid arthritis and SLE. The described C1q-PA-ELISA is a simple and inexpensive method for detection of C1q-binding immune complexes. The reproducibility is acceptable and the sensitivity is higher than for most IC-methods based on C1q-binding.
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PMID:Estimation of immune complexes by a microplate-adapted C1q-Protein A enzyme-linked-immunosorbent-assay (C1q-PA-ELISA). 633 38

An enzyme-immunoassay for the quantitative determination of circulating immune complexes in human serum is described. The technique uses alkaline phosphatase-conjugated anti-human IgG to detect immune complexes bound to solid phase C1q. This assay is sensitive detecting 4 ng/ml to 60 micrograms/ml aggregated IgG. First data from normal individuals and patients with systemic lupus erythematosus show that this method is specific and sensitive for detection of circulating immune complexes.
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PMID:[Demonstration of circulating immune complexes using a C1q-solid phase enzyme immunoassay]. 636 Jan 66

We developed a simplified, relatively rapid, inexpensive, antigen-nonspecific, enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G (IgG)- and C3-containing circulating immune complexes (CICs), adapted from a solid-phase anti-C3 radioimmunoassay (RIA). Standards (containing purified, heat-aggregated IgG and fresh human serum) or samples were allowed to react with goat F(ab')2 antihuman C3 bound to the matrix of microtiter plates. Then alkaline phosphatase conjugated to goat IgG fraction antihuman IgG was added, followed by p-nitrophenylphosphate, optical densities determined, and concentrations of CICs calculated. We found excellent correlations between serum and plasma CIC levels by either ELISA (r = 0.95, p less than 0.01) or RIA (r = 0.89, p less than 0.01). Furthermore, ELISA quantitation of CICs correlated well with RIA (serum, n = 75, r = 0.64, p less than 0.01; plasma, n = 101, r = 0.56, p less than 0.01). By ELISA we found 32 normal subjects had 38 +/- 12 micrograms CIC/ml in serum and 34 +/- 10 micrograms CIC/ml in plasma. Patients with systemic lupus erythematosus (39% of 27 patients, p less than 0.05) had significantly elevated CIC levels compared with normal (serum, 157 +/- 50 micrograms/ml, p less than 0.01; plasma, 89 +/- 23 micrograms/ml, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:An enzyme-linked immunoassay for detection of IgG- and C3-containing circulating immune complexes: comparison with a radioimmunoassay and quantitation in patients with rheumatic diseases. 638 73


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