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At least 775 records · Page 43Linked to original sources
PubMed1987

Measurement of immune complexes with the liquid phase C1q binding assay: ten years experience in a routine diagnostic laboratory.

We describe our 10 years experience in assaying over 15,000 clinical specimens for immune complexes (IC) using the C1q binding assay. Normal ranges were initially established using a large panel of blood donor sera and precision of the assay was optimized by inclusion of heat aggregated IgG (HAGG) as standards. Nevertheless some variability was observed due to variation in C1q binding from batch to batch and with aging of this reagent. In an empirically selected 2 year period involving over 3,000 clinical specimens, 25% had elevated concentrations of IC. Of these the majority were from patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), other connective tissue disorders, infective endocarditis (IE), diffuse interstitial lung disease (DILD) and vasculitis (VASC). In RA, IE and VASC, significant correlations were observed between concentrations of IC and rheumatoid factor (RF) and the addition of a purified monoclonal RF to normal serum caused increased C1q binding. Longitudinal studies in RA and IE demonstrated a striking decline in IC in response to effective treatment. We conclude that the measurement of IC provides little additional useful diagnostic information in those diseases associated with high levels of RF but appears more useful in disorders such as SLE, IE and DILD in which RF is absent or present in low concentration. Sequential monitoring of IC in RA and IE reflects response to treatment.

Antigen-Antibody Complex↗
PubMed1987

Dense deposit disease: its possible pathogenesis suggested by an observation of a patient.

A girl, aged 8, was admitted to a hospital in a state of nephrotic syndrome of one year's duration. The renal biopsy showed mesangial and endocapillary proliferations with lobulation. Dense deposit was not demonstrated by electron microscopy, but lamellation of the lamina densa was found in most of the capillary loops. Her condition was improved by steroid treatment in a few months, but moderate proteinuria persisted. Five and half years later, follow-up biopsy showed typical pathological features of dense deposit disease. It is suggested that the lamellation of the lamina densa in the first biopsy could be related to the dense alteration of glomerular basement membrane in the second biopsy.

Basement Membrane↗
PubMed1978

'In vitro' study of a reaction between the complement system and cellular DNA.

A direct reaction between the complement system and DNA in nuclei was demonstrated in vitro by an indirect immunofluorescence technique using cryostat-cut sections of rat liver as a substrate. This reaction occurred at physiological conditions of pH and molarity and was abolished by pre-treatment of the tissue sections by DNase. It begins by the fixation of C1q and involves the fixation and probably the activation of apparently all the components of the classical pathway of the complement system. The pattern of fluorescence given by this reaction was similar to the pattern given by anti-DNA antibodies present in sera from systemic lupus erythematosus (SLE) patients.

Animals↗
PubMed1979

Possible C1q bypass loop activation in the haemolytic uraemic syndrome.

Ultrastructural and immunofluorescent microscopic studies were performed on renal tissue obtained from nine patients during the acute and convalescent phase of the haemolytic uraemic syndrome (HUS). All had glomerular deposits of IgM in the absence of circulating immune complexes. This was associated with deposition of C1q during the acute phase, and properdin and C3 during the convalescent phase. C4 was consistently absent. Since such a pattern of complement deposition does not fulfil criteria either for alternate or classical pathway activation, the possibility of C1q bypass loop activation by IgM is suggested.

Child↗
PubMed1979

Immunofluorescence studies of dense deposit disease. The presence of railroad tracks and mesangial rings.

Immunopathologic analysis was carried out on renal tissue from patients with membranoproliferative glomerulonephritis, nine with type I and nine with type II (dense deposit disease). A specific finding in all patients with type II, but not type I, was the presence of C3 along the margin but not within the central portion of dense deposit material in the glomerular basement membrane giving a double linear appearance (railroad tracks); C3 was also present within the mesangium, outlining numerous circular structures (mesangial rings). By phase contrast, electron microscopy, and dual label fluorescence studies, the railroad tracks and mesangial rings were shown to outline dense deposit material. Mesangial rings contained properdin (four of nine patients); railroad tracks contained properdin (five of nine patients) and C4 (four of nine patients); no other complement components or immunoglobulins were present. Studies using rhodamine-conjugated rabbit antibody to human glomerular basement membrane demonstrated no reactivity with the dense deposit material itself. In type I and to a lesser extent in type II, granular deposits of C3, C4, properdin, IgM, and IgG were present along the glomerular basement membrane, suggesting that immune complexes play a role in both diseases. Dense deposit transformation of the glomerular basement membrane may be a consequence of a highly specific injury.

Autoantibodies↗
PubMed1979

Circulating and tissue-bound immune complex formation in murine malaria.

Immune complex formation during Plasmodium berghei infection of OF1 mice was investigated. Circulating immune complexes (CIC) were detected by the Clg-binding assay and the conglutinin-binding solid-phase assay in lethal or drug-limited infections. CIC appeared on day 9 of infection, peaked on day 11, and disappeared only after complete cure of the infection. Analysis of the immune complexes detected by the Clq-binding assay revealed the following characteristics: sedimentation coefficients of 13S to 21S, resistance to DNAse, and selective removal by filtration through protein A bound to Sepharose. Glomerular deposits of IgM preceded the appearance of CIC, whereas deposits of IgG and C3 were concomitant with the appearance of CIC. Tissue-bound immunoglobulins were also found in the choroid plexus. The appearance of anti-malarial antibodies and malarial antigens in the serum was closely associated with a depression of C3 levels and the presence of CIC. Drug treatment was followed by normalization of C3 levels, and clearance of both CIC and malarial antigens.

Animals↗