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)

A sensitivie and simple procedure for the detection and quantitation of soluble complement (C)- fixing immune complexes in sera of patients with various disease states has been developed by utilizing C receptors on Raji cells. These cells lack membrane-bound immunoglobulin but have receptors for IgG Fc, C3b, C3d, and possibly with other C proteins. Uptake experiments showed that both aggregated human gamma globulin (AHG) and 7S IgG bound to receptors for IgG Fc; however, AHG reacted with C bound to cells only via receptors for C and this binding was much more efficient than via IgG Fc receptors. AHG was used as an in vitro model of human immune complexes and its uptake by Raji cells was quantitated by 125I-radiolabeled antihuman IgG. The limit of sensitivity of this test was 6 mug AHG/ml serum. The ability of Raji cells to detect AHG in serum depended on the amount of radioactive antibody used and the size of aggregates. The presence of an excess of C somewhat inhibited binding of AHG containing C to Raji cells. The efficient binding of AHG by receptors for C on Raji cells was used for the detection and quantitation of immune complexes in human sera. Raji cells were incubated with sera to be tested and then reacted with excess radiolabeled antihuman IgG; the amount of radioactivity bound to the washed cells was determined and referred to a standard curve of radioactive antibody uptake by cells previously incubated with increasing amounts of AHG in serum. Thereby immune complexes were detected and quantitated in serum hepatitis, systemic lupus erythematosus, vasculitis, subacute sclerosing panencephalitis, dengue hemorrhagic fever, and malignancies.
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PMID:The Raji cell radioimmune assay for detecting immune complexes in human sera. 12 62

Immune complexes were detected in 51 sera from patients with a variety of immunological diseases; 14 systemic lupus erythematosus (SLE); 14 infectious mononucleosis (IM); 12 rheumatoid arthritis (RA) and 11 subacute bacterial endocarditis (SBE). Three methods were used to detect complexes: the fluid--phase Clq binding assay (Clq.BA); the solid--phaseClq binding assay (Clq.SP) and the Raji cell radio-immunoassay (RIA). Modification of the Clq.SP and the Raji cell RIA by use of monospecific antisera to immunoglobulins G, A and M enabled the class of antibody in the immune complexes to be determined. Antibodies of all three classes were found in each disease, the predominant ones being IgG and IgM in SLE and SBE, IgM and IgA in RA and IgM in IM.
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PMID:The detection of immune complexes of different immunoglobulin class. 29 21

Samples of serum from 45 patients with different clinical forms of leprosy and from 17 patients with systemic lupus erythematosus were studied in parallel for circulating immune complexes with use of two different in vitro tests adjusted to the same degree of sensitivity. The Clq deviation test relied upon the reaction of the complement component Clq with immune complexes. The Raji cell test detected complement-fixed immune complexes that bound to the complement receptors on cultured, bone marrow-derived lymphocyte-like Raji cells. Thirty (67%) of 45 patients with leprosy showed immune complexes according to the Clq deviation test; however, only two (7%) of the 30 samples of sera with positive Clq test results were positive by the Raji cell test. In contrast, 54% of 13 samples of sera from patients with systemic lupus erythematosus positive by the Clq test were positive according to the Raji cell test. Since Clq is known to react with DNA as well as with bacterial antigens, the Clq reaction may in fact be detecting antigenemia in many instances. Considerable caution is warranted in application of sensitive screening tests for assay of circulating immune complexes in various states of infectious diseases.
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PMID:Discrepancy between Clq deviation and Raji cell tests in detection of circulating immune complexes in patients with leprosy. 33 Jul 68

A panel of three immune complex (IC) assays was used in this study to test sera from patients with glomerulonephritis (GN): the Raji cell radioimmune assay (IRCA), the radio-labeled C1q binding assay (IC1qBA), and the microcomplement consumption test (MCT). The sensitivity and specificity of each assay was evaluated in preliminary studies, and the greater sensitivity (5 to 10microgram of aggreagated human gamma-globulin (AHG) per ml of serum) and IgG specificity of the IRCA was apparent. Problems related to the preliminary heat inactivation of test sera, the interaction of C1q with substances other than IC, and the effects of suboptimal storage of test sera were experienced with the MCT and, to a lesser extent the IC1qBA. The individual reactivities of the different assays were exploited by using them in combination. Thus ICs were detected by one or more of the assays in 87% of patients with systemic lupus erythematosus (SLE), 65% of patients with GN associated with other systemic diseases, and 39% of patients with primary GN. ICs were detected more frequently in patients with acute GN than chronic GN, and in patients with low serum C3, C4, and properdin factor B (C3PA) levels.
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PMID:Detection of circulating immune complexes in patients with glomerulonephritis. 34 Jul 63

The objectives of these studies were to quantify the amounts of immunoglobulin (Ig)G bound to peripheral blood neutrophils from patients with systemic lupus erythematosus (SLE) and to determine the contributions of soluble immune complexes or anticell antibodies to the levels of IgG neutrophil-binding activity in SLE sera. Neutrophil-bound IgG, determined by a sensitive antiglobulin inhibition assay, was elevated in 7 out of 14 SLE patients compared with values obtained in 23 normal controls. The levels of IgG neutrophil-binding activity in sera were elevated in 22 of 38 patients with SLE over the values seen with 36 normal sera. No correlation was found between the peripheral blood neutrophil counts in the SLE patients and the values for IgG adherent to the cells or serum cell-binding activity. The sera from 18 patients with SLE were fractionated by gel filtration. Elevated levels of IgG neutrophil-binding activity were found in 11 of the 18 G-200 excluded pools and in 13 of the G-200 IgG pools. In nine sera elevated levels were observed in both pools. F(ab')2 fragments of IgG from SLE sera bound to normal polymorphonuclear leukocytes in greater amounts than F(ab')2 fragments of IgG from normal sera. A significant correlation existed between the values of IgG neutrophil-binding activity found in SLE sera and those obtained with both the G-200 excluded and IgG pools. Sucrose density gradient fractionation of four sera from SLE patients confirmed the presence of both large (greater than 19S) and intermediate-sized (7S-19S) cell-binding immune complexes as well as of monomeric IgG antibodies to neutrophils. The levels of IgG neutrophil-binding activity in the SLE sera correlated well with the results obtained with the Raji cell assay for immune complexes as well as with the titer of antibodies to nuclear antigens. These data indicate that circulating neutrophils from patients with SLE commonly have increased amounts of cell-bound IGG. The elevated levels of IgG neutrophil-binding activity in the sera of these patients are caused by both soluble immune complexes and antibodies reactive with neutrophils.
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PMID:Neutrophil-binding immunoglobulin G in systemic lupus erythematosus. 47 75

The C1q solid phase and Raji cell radioimmune assays were used to determine the frequency of detectable circulating immune complexes in patients with glomerulonephritis. In this study, 46% of 56 patients with glomerulonephritis had evidence of circulating immune complexes. More important, circulating immune complexes were associated with some, but not other, types of glomerulonephritis. Thus, immune complexes were detected in lupus glomerulonephritis (9/9 patients), rapidly progressive glomerulonephritis (5/6 patients), and acute nephritis (5/6 patients), but not in IgA-IgG glomerulonephritis (0/7 patients), or membranous glomerulonephritis (0/8 patients). The Raji cell radioimmune assay and the C1q solid phase radioimmune assay showed concordance of 79% in the detection of circulating immune complexes. Serial determinations, in general, showed either persistence of a negative or positive result of conversion of positive to negative.
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PMID:Application of the solid phase C1q and Raji cell radioimmune assays for the detection of circulating immune complexes in glomerulonephritis. 65 39

The Sm-D(D1) small nuclear ribonucleoprotein (snRNP) polypeptide is a major target of autoantibodies diagnostic for systemic lupus erythematosus. The cDNA encoding the protein from Raji cells was expressed in Escherichia coli as a fusion protein with anthranilate synthase (TrpE-Sm-D). When tested by protein blot, the recombinant polypeptide was strongly immunoreactive under defined blotting conditions, which appear to facilitate the refolding of the polypeptide into a native conformation. Multiple translational fusions between the trpE gene and fragments encompassing the length of the Sm-D coding sequence were constructed for epitope mapping. The results describe two general patterns of anti-Sm reactivity: (i) antibodies that recognize only the full-length antigen and are presumably directed against discontinuous epitopes, and (ii) antibodies that recognize the carboxy terminus of the antigen which embodies an extended/charged structure.
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PMID:Mapping of the immunoreactive domains of a small nuclear ribonucleoprotein-associated Sm-D autoantigen. 128 May 41

The U snRNP associated B'/B polypeptides are primary targets of Sm autoantibodies in patients with systemic lupus erythematosus. We have bacterially expressed a Sm-B'/B autoantigen from Raji cells as a fusion with the anthranilate synthase protein from Escherichia coli. The recombinant Sm-B'/B fusion displays comparable immunologic reactivity to the native protein when tested with both monoclonal and polyclonal antibodies. To map Sm-B'/B epitopes, we constructed a series of 12 anthranilate synthase fusions spanning different regions of Sm-B'/B and tested such fusions on immunoblots against a panel of characterized sera. In this manner, we have identified six epitopes, five of which overlap the proline-rich carboxyl-terminus of the protein. Some of these epitopes appear to be conformational. The human sera tested can be divided, according to the epitopes they recognize, into six groups. Finally, we have shown that anti-Sm recognition of the (U1)RNP-specific A protein is attributable to cross-reactivity between the Sm-B'/B and A autoantigens.
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PMID:Heterologous expression and epitope mapping of a human small nuclear ribonucleoprotein-associated Sm-B'/B autoantigen. 168 87

The putative cross-reaction of anti-DNA antibodies with "lupus-associated membrane proteins (LAMP)" on the surface of intact Raji cells was examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting analyses. Cell surface proteins of 14, 17, 18, 33 and 34 kDa were detected by monoclonal anti-double-stranded (ds) DNA antibodies and the sera of patients with systemic lupus erythematosus (SLE) in active states, but were not detected by the sera of SLE patients in inactive states, nor in healthy controls. However, pre-treatment of these anti-DNA antibodies with DNase I markedly reduced the reactivity to the cell surface proteins. Judging from the electrophoretic mobility, these proteins were identical with histones, and purified histones inhibited the reaction of anti-DNA antibodies with the cell surface proteins. Moreover, affinity-purified antihistone antibodies could demonstrate histones in the Raji cell surface proteins. Thus, we conclude that "cross-reaction" of anti-DNA antibodies with LAMP is due to DNA-anti-DNA immune complexes which could react with cell surface histones.
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PMID:Interpretation of the cross-reactivity of anti-DNA antibodies with cell surface proteins: the role of cell surface histones. 230 91

The immunoglobulin (Ig) class of the antibody component of circulating immune complexes (IC) may be an important determinant of their pathogenicity. This study reports the development of a fluorometric immunoassay, using Raji cells as solid phase component and detection by flow cytometry, for the measurement of IC containing IgG, IgM, IgA and IgE. Analytic specificity of the method was established and diagnostic sensitivity determined in groups of patients with various disorders. In a detailed study of 44 patients with systemic lupus erythematosus (SLE), elevated levels of IC were observed in the majority of patients, the prevalence of the respective Ig subclasses within the patient group being IgG-IC (93%); IgM-IC (77%); IgA-IC (59%); IgE-IC (52%). Raised levels of IC (of all classes) correlated with disease activity. Longitudinal study of a patient with acute cerebral SLE revealed elevated IC levels of all four Ig classes at presentation which fell during treatment, coincident with normalization of complement values. The biological consequences of IC of various Ig subclasses is discussed with particular reference to a possible mechanism of IgE-IC mediated tissue damage.
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PMID:Measurement of circulating immune complexes containing IgG, IgM, IgA and IgE by flow cytometry: correlation with disease activity in patients with systemic lupus erythematosus. 253 27


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