Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Complement C3d”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1986

Different patterns of C3 and C4 activation in the varied types of juvenile arthritis.

Quantitative assays for C3 and C4 activation were carried out simultaneously on blood from children with varied types of juvenile arthritis. Factor VIII-related antigen was also measured as an indicator of vascular damage. In active systemic juvenile arthritis, the C4d/C4 ratio was frequently elevated and was usually associated with elevated C3d/C3 ratios and elevated concentrations of factor VIII-related antigen. Children with chronic polyarticular arthritis, no matter which forms of onset they had had, also had increased levels of the C4d/C4 ratio, C3d/C3 ratio, and factor VIII-related antigen, but these were less consistent and were not associated with each other. In contrast, in pauciarticular arthritis there was a uniquely isolated increase in the C3d/C3 ratio. This work implies that there are different mechanisms responsible for complement activation in the different types and at different stages of juvenile arthritis.

Adolescent↗
PubMed1991

C3 activation products, C3 containing immune complexes, the terminal complement complex and native C9 in patients with rheumatoid arthritis.

Complement activation products, C9 and C3-containing circulating immune complexes (CIC), were evaluated in plasma and synovial fluid (SF) from patients with rheumatoid arthritis (RA) and osteoarthritis. C3 activation products and the fluid phase terminal complement complex were considerably elevated in SF from RA patients reaching levels five- to eighttimes that in plasma, consistant with a local activation of the whole cascade in the joints. The results emphazise the importance of detecting C3 activation by neoepitope expression instead of single fragment determinations. The concentration of native C9 was lower in synovial fluid compared with plasma, consistant with the excessive local complement activation. Increased CIC levels which correlated with the degree of complement activation were also found in the SF from the RA patients.

Adult↗
PubMed1992

Immunohistological study of subretinal membranes in age-related macular degeneration.

An immunohistological study was performed on 6 specimens of subretinal membranes obtained surgically from patients suffering from age-related disciform macular degeneration. using immunoperoxidase procedures, we found in those membranes large amounts of IgG, IgA and IgE as well as C1q, C3c and C3d complement components diffusely distributed in the connective stroma and within the new blood vessel walls. Moreover, subretinal membranes contained numerous isolated HLA-DR- and -DQ-expressing cells, including glial, pigment epithelial and vascular endothelial cells. Monoclonal antibodies to immunocompetent cells disclosed only rare B and natural killer lymphocytes or suppressor-cytotoxic T cells, as well as some monocytes. These results show that immune phenomena are involved in proliferative changes associated with subretinal neovascularization. In addition, they suggest there are interactions between the immune system and peptide growth factors.

Antibodies, Monoclonal↗
PubMedDate not supplied

Analysis of polyethylene glycol precipitates from SLE sera: antibody enrichment in association with disease activity.

Twenty two systemic lupus erythematosus patients were assessed clinically for periods of up to six years. Polyethylene glycol precipitates of serial serum samples were analysed for the presence of autoantibodies by specific enzyme-linked immunoabsorbent assays. Increased enrichment of anti-Ro(SSA) was found to correlate with disease activity. Longitudinal studies of individual patients showed an association between disease exacerbation and enrichment of anti-Ro(SSA), anti-La(SSB) and anti-ssDNA. Circulating immune complexes isolated by anti-C3 affinity chromatography were also found to contain anti-Ro(SSA), anti-La(SSB) and anti-ss DNA and fixation of complement by complexes could be demonstrated. Enrichment of these autoantibodies in renal eluates of two patients with diffuse proliferative glomerulonephritis provided further evidence for a pathogenic role of these immune complexes.

Antigen-Antibody Complex↗
PubMed1991

[Value of the Coombs test in ABO incompatibility].

We studied the ABO haemolytic disease of the newborn in our neonatal unit to consider their serological aspects and clinical importance. 21% of all pregnancies were ABO incompatibles. The direct antiglobulin test was positive in 46 (11.3%) of them. The Elution was positive in all the newborns with direct antiglobulin test positive (Cd+). The anti-A o anti-B antibodies concentration in mothers was higher than 1/128 in 38 (84%). The C3d complement fraction was activated in two newborns. The infants Cd+ were born to group O mothers in all cases, and nobody was premature. Twelve (26%) of Cd+ presented jaundice which need phototherapy, and one moreover exchange transfusion. The direct antiglobulin test is very useful for detect the liable newborns of serious jaundice; therefore, we thing that is suitable to make this test in infants born to group O mothers. The newborns Cd+ did not have significant anemia at first three months of life.

ABO Blood-Group System↗
PubMed1990

[Recurrent post-infectious immune complex glomerulonephritis with persistent activation of the alternative complement pathway].

Recurring upper respiratory tract infections in a previously healthy 4 years old boy led to an acute nephritic syndrome requiring haemodialysis. Renal biopsy showed poststreptococcal like immune complex glomerulonephritis with subepithelial humps, C3 deposition and crescent formation. Renal function improved after methyl-prednisolone pulse therapy. Two relapses occurred in the following six months which responded to immunosuppressive therapy. 21 months following the first presentation the boy has normal glomerular filtration rate but persistent glomerular proteinuria and haematuria. Detailed complement analyses revealed a persistent activation of the alternate pathway.

Child, Preschool↗
PubMed1989

Paediatric coeliac disease and dermatitis herpetiformis: differences in complement activation in relation to diet.

We studied complement (C') involvement in paediatric coeliac disease (CD) and dermatitis herpetiformis (DH) in relation to lesions and function of enteric mucosa and to diet. For this purpose, 50 children affected by CD and 42 affected by DH were subdivided in 3 groups: in the first (I) were included subjects in free diet, in the second (II) children during gluten-free diet (GFD) and in the third (III) subjects after gluten reintroduction in diet. Only in CD we found significant modifications of some C' parameters. In fact C3 and C4 levels increase in II group in GFD (respectively p less than 0.02 and p less than 0.03) and result inversely correlated to an arbitrary score for the evaluation of the enteric histological lesions (p less than 0.02 and p less than 0.01). C3d/C3 ratio levels, as catabolic index of C3, result always greater than normal in both diseases, but significantly decrease only in II group of CD children (p less than 0.02), where they result also positively correlated to the histological score (p less than 0.05). Circulating immune complex-like material is higher in DH, but incidence of pathological values decrease in II group only in CD (p less than 0.04). These data suggest probable significant differences in the pathogenetic mechanisms of CD and DH involving C'.

Antigen-Antibody Complex↗
PubMed1989

Complement receptors.

Explore the source record for details and available documents.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1987

Quantification of the complement receptor function on polymorphonuclear leukocytes: its significance in patients with systemic lupus erythematosus.

The function of complement receptors (CR1) on polymorphonuclear leukocytes (PMN) was assessed by C3b mediated binding of immune complexes (IC) to PMN. The binding of IC to CR1 on PMN depends on the activation of the classical complement pathway and was inhibited by the antibody to CR1 or C3b. CR1 function of PMN from patients with systemic lupus erythematosus was reduced compared with those from normal controls or patients with rheumatoid arthritis.

Antibodies, Monoclonal↗
PubMed1987

Complement activation following multiple injuries.

Complement activation was evaluated by assay of plasma C3dg and the terminal complement complex (TCC) in 19 patients with multiple injuries. In the nine patients with thoracic involvement, statistically significant increase of plasma TCC was found at first sampling (average 90 min post-trauma), and of C3dg after 24 hours. Such increase was not found in the ten patients without thoracic involvement. Heightened granulocyte elastase activity was found in bronchial lavage fluid 90 min after the trauma in three patients with thoracic injury. Pulmonary insufficiency (pO2/FiO2 less than 16 kPa on intermittent positive-pressure ventilation) arose in four patients. All four had raised plasma levels of TCC or C3dg on arrival at the hospital. Six patients with complement activation did not show pulmonary insufficiency. Although the series was relatively small, the results indicate that thoracic injury is particularly associated with complement activation, and that complement activation alone does not suffice to produce post-traumatic pulmonary insufficiency.

Adolescent↗
PubMed1985

Complement activation in primary biliary cirrhosis: an in vitro model.

Increased concentrations of C3dg were demonstrated in plasma from patients with primary biliary cirrhosis (PBC), indicating in vivo activation of C3. Rapid spontaneous C3 cleavage by the classical pathway was observed in vitro in serum and in EDTA plasma reconstituted with Ca++ and Mg++, suggesting the presence of complement-activating substances. On incubation with fresh normal serum, purified polyclonal IgM from patients with PBC induced C1 activation, C4 cleavage, and C3dg formation. No C3 cleavage was observed when PBC-IgM was incubated with a C2-deficient serum. We suggest that the complement activation in vivo in PBC, which occurs predominantly by the classical pathway and is characterized by increased concentrations of C1 activation complexes, decreased C4 concentrations, and hypercatabolism of C3, is attributable to an abnormal IgM population.

Complement Activation↗
PubMed1985

Immunonephelometric quantitation of complement split product (C3d) plasma levels in rheumatic disease.

A simple method is described for routine quantitative determination of C3d by laser nephelometry after precipitation of intact C3 by polyethylene glycol. Plasmas from 292 patients with different types of rheumatic disease was tested. Elevated C3d levels were a far more common finding than low levels of complement components C3 or C4, but despite the increased sensitivity, the test only seemed diagnostically useful for systemic lupus erythematosus and MCTD. Though a better test than the quantitation of C3 and C4, the value of C3d determination in rheumatic disease seems to be limited.

Adult↗
PubMedDate not supplied

Epitope specificities and quantitative and serologic aspects of monoclonal complement (C3c and C3d) antibodies.

Twenty-two monoclonal antibodies to human C3c and ten to C3d were obtained by hybridization after the immunization of mice with complement-coated human red cells and/or purified human complement components. C3c antibodies were variable in their agglutination reactions with cells coated with C3 by antibody in vitro; more consistent and potent reactions with these cells were observed with anti-C3d, and all anti-C3d reacted with red cells coated with C3 in vivo. Immunoradiometric assays were used to estimate antibody concentration, affinity, and epitope specificity. The antibody content in ascitic fluids varied from less than 0.1 mg per ml to 5.6 mg per ml. The estimated values of antibody affinities for Sepharose-coupled C3 ranged from 2.8 X 10(6) l per M to 5.0 X 10(8) l per M; on average, IgM antibodies had higher affinities than IgG antibodies. Competitive binding assays showed that the monoclonal antibodies recognized at least seven different epitopes, four on the C3c and three on the C3d fragment of C3. When the results of serologic and quantitative assays were compared, no convincing relationship was found between serologic performance and epitope specificity, antibody concentration, or affinity. IgM antibodies generally gave higher agglutination scores than IgG antibodies, and Ig class was the only useful predictor of serologic efficacy.

Animals↗
PubMed1985

Correlation of disease activity with circulating immune complexes (C1qbA) and complement breakdown products (C3D) in patients with systemic lupus erythematosus. A prospective study.

Most biologic effects of immune complexes are mediated through the activation of the complement system. The relationship between lupus disease activity and the presence of C3 breakdown products (C3d) and circulating immune complexes (CIC) as demonstrated with the C1q binding assay (C1qbA), was evaluated. Nearly all 13 systemic lupus erythematosus (SLE) patients had a stable disease course in this prospective study, nevertheless, in each patient the profiles of the serologic parameters were quite different. Despite the small number of investigated patients (13), it is concluded that irrespective of the disease activity, the serologic parameters could be either positive or negative. No relationship could be obtained between disease activity and the presence of C3d and/or CIC. Nor was there any evidence that the presence of CIC would indicate increased levels of C3 breakdown products (C3d). This observation argues against a pathogenetic significance of CIC detected by the C1qbA in SLE. In conclusion, the supposed link between the presence of CIC, consumption and activation of the complement system, and the activity of SLE needs further study.

Adult↗
PubMed1984

Determination of complement breakdown fragments C3d and its subfragments in health and disease.

The breakdown products of the third component of complement in approximately 400 samples were measured by rocket immunoelectrophoresis and two-dimensional electrophoresis using the method of Brandslund et al [3]. It was confirmed that the measurement of the C3d level provides useful information on increased C3 consumption irrespective of the synthetic rate. Furthermore, three subfragments with C3d but without C3c antigenicity were distinguished, which were designated as C3d1, C3d2, and C3d3. The subfragment C3d3 which migrated to the most anodal side was a predominant component in the plasma from patients with autoimmune diseases. Little C3d3 subfragment was detected in normal plasma and in normal sera incubated in vitro for 24 hr. Even in the normal sera converted completely in vitro which contained little intact C3, only a limited amount of C3d3 was detected. In the plasma from postsurgical patients in whom activation of the complement system was considered to be in an acute phase, C3d3 was detected, but the C3d2 level was higher than the C3d3 level. In the plasma from patients with systemic lupus erythematosus having the normal C3d level, C3d3 was a major fragment. It is predicted that the preponderant presence of C3d3 in plasma could be the result of chronic continuous complement activation by immune complexes.

Arthritis, Rheumatoid↗
PubMed1984

In situ characterization of cell infiltrates in human dental periapical granulomas. 2. Demonstration of receptors for the complement components C3b and C3d.

The inflammatory cell infiltrates in human dental periapical granulomas were studied through the demonstration of receptors (R) for fragments C3b and C3d of the complement component C3, C3bR and C3dR were detected in cryostat sections by the closed chamber hemadsorption technique. Sheep erythrocytes sensitized with rabbit IgM antibody and coated with human C3B or C3d were used as indicator cells. Of the 62 granulomas studied, 23 showed strong or moderate C3bR activity, and weak C3dR activity was detected in 5 out of 25 specimens. The C3bR activity was abolished by treatment with 0.25 mM periodic acid, indicating that carbohydrate is a part of the C3bR. Using an antiserum to C3R as first layer in indirect immunofluorescence experiments, the C3R was localized to cell membranes. The low C3dR activity indicates that a minor part of the mononuclear cells in the human periapical granulomas were B lymphocytes.

Adult↗