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Results for “Complement C3c”

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PubMed1999

[Complement and serum immunoglobulins in homozygous and heterozygous sickle cell anemia in Senegal].

Sickle cell disease is an hereditary hemoglobinopathy syndrome which provokes deglobulization crisis and infectious complications. These infectious diseases may be due to a permanent activation of the immune system. The aim of our study was to explore alternative pathway by measuring C3 complement and the classical pathway by C4 complement. The level of immunoglobulins IgA, IgG and IgM was also measured in the subjects sera. Thirty homozygous sickle cell anemia (SS), 25 heterozygous (AS) and 34 controls subjects (AA) were recruited in the Hôpital d'Enfants Albert Royer (HEAR), Fann hospital and Centre National de Transfusion Sanguine (CNTS). Radial Immunodiffusion (RID) technics using specific antisera for C3c, C4c, IgA, IgG and IgM were used in our study. Homozygous SS proved an increase level of IgA (50%, p < 0.003) and IgG (47%, p < 0.003), unlike of IgM level. The C3c complement decrease significantly in (27%) of homozygous SS patients (p < 0.0005) unlike of C4c level. This low level of C3 and IgG in sickle cell homozygous patients can explain the higher susceptibility to infection in these patients. Normal level of C4 and low level of C3 show activation of alternative pathway. Heterozygous AS showed a normal level of C4, C3 and immunoglobulins. Our results suggests a direct involvement of the complement system in sickle cell disease and the depletion of C3 registered was a possible cause of increased susceptibility to infections in patients with homozygous sickle cell anemia.

Adolescent↗

PubMed1993

Isolation of the porcine complement activation fragments C3c and C3d and their use in the preparation of monospecific antibodies.

The hemolytic test to date has been the sole analytic technique applied to study the complement reaction in the swine. To improve the analytical possibilities for this species we have developed polyclonal antibody reagents with specificities for the C3c and C3d activation fragments of swine C3. Access to these reagents, by which activation products can be analysed in tissues and biological fluids, will offer new possibilities for a more precise analysis of the complement reaction.

Animals↗

PubMed2001

Human xenoreactivity is reduced in mice bearing porcine antisense alpha(1,3) galactosyltransferase cDNA.

AIM: To explore the effect of antisense alpha(1,3) galactosyltransferase alpha(1,3) GT cDNA on production of Gal alpha(1,3) Gal (Gal epitope) xenoantigen in vivo. METHODS: Transgenic mice bearing the porcine antisense alpha(1,3) GT cDNA (nt 1alpha-640) were generated by pronuclei microinjection method. The integration of transgene was identified by PCR and Southern-blot analysis. The expression of murine alpha(1,3) GT was characterized by RT-PCR. Morphology of the spleen was examined by histological technique. Gal epitope was detected by immunofluorescent analysis. Binding of human natural xenoantibodies (IgM and IgG) and complement (C3c) to cells from mice was determined by flow cytometric assay. RESULTS: Transgenic mice bearing the porcine antisense alpha(1,3) GT cDNA were born healthy and developed normally. However, necrosis occurred in the spleen of some mice heterozygous for transgene. Cell surface Gal epitope in transgenic heterozygotes was evidently reduced. Substantially less (30 % - 60 %) xenoantibodies in human serum bound to cells from a variety of tissues of transgenic heterozygotes compared with wild-type controls. Consequentially, human complement activation on cells from these mice was reduced by 40 % - 50 %. CONCLUSION: Human xenoreactivity could be effectively reduced by inhibiting the expression of alpha(1,3) galactosyltransferase with an antisense gene.

Animals↗

PubMed1999

The effects of methylprednisolone on complement, immunoglobulins and pulmonary neutrophil sequestration during cardiopulmonary bypass.

In this study, the authors administered high dose (30 mg/kg body weight i.v.) methylprednisolone before cardiopulmonary bypass to observe the effects on complement, immunoglobulins and pulmonary neutrophil sequestration. Fifty patients undergoing valve replacements were included in this study. Patients were divided into two groups: group I (20 patients) served as control and did not receive methylprednisolone, group II (30 patients) received methylprednisolone. Blood samples for complements (C3c and C4) were taken, before cardiopulmonary bypass, at 5, 10 and 30 min intervals from the end of cardiopulmonary bypass, after reversal of heparin with protamine infusion, and after skin closure. Blood samples for immunoglobulins were taken before cardiopulmonary bypass, 30 min after onset of cardiopulmonary bypass and after skin closure. After onset of cardiopulmonary bypass, all C3c and C4 levels decreased in both groups. There was a significant decrease in C4 levels at end of cardiopulmonary bypass and after protamine infusion in group I compared with group II (P < 0.05). C3c levels in group I decreased significantly compared with group II after 30 min of cardiopulmonary bypass and after protamine infusion (P < 0.05). All immunoglobulin (IgG, IgM, IgA) levels were decreased in both groups, but the decrease in IgG was statistically significant after skin closure in group I compared with group II (P < 0.05). Pulmonary neutrophil sequestration was higher in the control group compared with the methyl-prednisolone group (P < 0.05). In conclusion, methylprednisolone administration before cardiopulmonary bypass may prevent the harmful effects of complement activation, immunoglobulin denaturation and neutrophil sequestration in the pulmonary capillary system.

Adult↗

PubMed1980

Comparison of radial immunodiffusion and laser nephelometry for quantitating some serum proteins.

After quantitating immunoglobulins G, A, and M and complement C3c and C4 in serum by using a laser nephelometer coupled with a data processor, I compared these results with values obtained by an early-readout radial immunodiffusion method. Day-to-day precision was better for nephelometry than for radial immunodiffusion for all proteins analyzed. The average coefficient of variation was 6.0% for nephelometry and 9.9% for radial immunodiffusion. Comparison of these methods gave ranked correlation coefficients of 0.945, 0.981, 0.932, 0.803, and 0.792 for IgG, IgA, IgM, C3c, and C4, respectively. Nephelometry gave significantly higher values than radial immunodiffusion for IgG, IgA, IgM, and C3c, and significantly lower values for C4 (p less than 0.001). Part of this bias was found to be due to the equation programmed in the data processor for calculating the standard curves. Within 95% limits, nephelometry gave higher normal ranges than radial immunodiffusion for IgG, IgA, and IgM. Other possible factors that can produce this bias are discussed.

Adolescent↗

PubMed1993

Immunological evaluation of erythema nodosum in tularaemia.

During two tularaemia outbreaks in the Bursa region of Turkey in 1991, a total of 98 patients were diagnosed and evaluated. Thirteen of these patients had erythema nodosum, which is accepted as a secondary skin manifestation. The patients with erythema nodosum, 21 patients without any skin lesions, and 20 healthy controls were studied. Comparable elevations of levels of IgG, IgA, and IgM were detected in the two tularaemia groups. There was no difference in complement C3c and C4 levels between the groups. All of the patients with erythema nodosum had elevated circulating immune complex (CIC) levels, when compared with the patients without skin lesions and the control group. The acute phase response (C-reactive protein [CRP] and erythrocyte sedimentation rate [ESR]) of the erythema nodosum group was significantly higher than the patients with normal skin, and healthy controls (P < 0.001). Serum transferrin levels were significantly decreased in both of the tularaemia groups (P < 0.001). Serum soluble interleukin-2 receptor levels (SIL-2R) were significantly elevated in both tularaemia groups (P < 0.001), and the elevation was more marked in the erythema nodosum group (P < 0.05). Histopathological evaluation of biopsies from two patients with erythema nodosum showed dermal oedema, a perivascular lymphocytic infiltrate, and panniculitis. No immunoglobulin or complement deposits were detected on immunofluorescence. Erythema nodosum in the course of tularaemia is associated with many immunological changes, although it is not clear whether these findings are related to the increased tissue response, or whether they play a role in the pathogenesis of the erythema nodosum.

Adolescent↗

PubMed1978

Immunological features of kala-azar.

Serum immunoglobulins, complement C3c, percentage of T and B cells, and skin reactivity to Leishmania were studied in ten cases of kala-azar. Immunoglobulin G was increased in a majority of these patients. The C3c level in two out of six patients tested was lower than normal. The percentage of T cells in peripheral blood of nine patients tested was reduced and in seven of these patients the percentage of B cells was elevated. After a full course of anti-kala-azar therapy the percentage of T and B cells remained the same in five patients studied. All the patients showed a negative skin reaction when they were tested with Leishmania antigen.

Adult↗

PubMed1983

Pregnancy-associated plasma protein levels at term in normal pregnancy, preeclampsia and essential hypertension.

The levels of protein associated with pregnancy (placental specific beta 1 glycoprotein, SP1, and pregnancy associated -alpha 2- globulin, alpha 2-PAG), immune function (complement, C3c) and inflammation (ceruloplasmin, C), were studied at term in groups of patients with normal and complicated primigravid and multigravid pregnancy. The levels of SP1 and C3c were similar in all the groups studied. In patients matched for parity, the levels of alpha 2-PAG were significantly lower than normal in preeclamptic primigravidas and in multigravidas with a history of preeclampsia in their first pregnancy. Ceruloplasmin levels were significantly elevated in preeclampsia patients and in patients with essential hypertension. It is suggested that reduced plasma alpha 2-PAG may be of prognostic value and have a role in the aetiology of preeclampsia whereas increased ceruloplasmin levels may be no more than an acute phase reactant resulting from pathological changes due to hypertension.

Ceruloplasmin↗

PubMed1992

The occurrence of pericapillary fibrin in venous hypertension and ischaemic leg ulcers: a histopathological study.

The presence of pericapillary fibrin and complement C3c in the ulcers of 19 patients with venous hypertension and 14 patients with ischaemic leg ulcers was investigated using histochemical and immunohistochemical techniques. There was deposition of fibrin around the capillaries in the central part of the ischaemic ulcers, and the venous hypertension ulcers, and in the non-ulcerated skin around one of the venous hypertension ulcers and two of the ischaemic leg ulcers. The deposition of fibrin is a secondary phenomenon that occurs in the area of ulcerated skin and does not play a major causal role in the formation of chronic leg ulcers.

Aged↗

PubMed1981

Antiglobulin-tests for detection of auto-immunohaemolytic anaemia during long-term treatment with ibuprofen.

Auto-immunohaemolytic anaemia is a very unusual complication during long-term treatment with ibuprofen. In order to detect the haemolytic antibodies involved, serum and erythrocytes from 87 patients were investigated after continuous treatment with an average daily dose of 1337 mg ibuprofen for some 6-47 months. Eight patients showed a weak or medium-positive antiglobulin test result with polyspecific anti-human serum. With monospecific anti-human serum, complement C3c and/or C3d were detected on the surface of 8 patients' erythrocytes, but none had biochemical parameters indicating haemolysis. None of the 87 patients had IgG, IgM or IgA on their erythrocytes. The findings neither indicated haemolysis present nor early stages in any of the four types of drug-induced auto-immunohaemolytic anaemia. The frequency of a positive antinuclear factor test (ANF) among patients treated with ibuprofen did not differ from that of healthy subjects in the same age group. The type of haemolysis associated with ibuprofen is discussed, but available data do not permit any definite classification. It is concluded that ibuprofen is a safe drug which rarely causes haemolysis and does not seem to cause induction of ANF.

Adult↗

PubMed1984

Complement in chronic secretory otitis media. C3 breakdown and C3 splitting activity.

Occurrence of in vivo C3 breakdown and in vitro C3 splitting activity was studied in serum and middle-ear effusion (MEE) samples from 30 children with chronic secretory otitis media (SOM). The MEE showed strongly elevated levels of both low- and high-molecular-weight C3 breakdown products, along with decreased factor B, C4, and C3 levels. Total hemolytic complement component activity was virtually absent from MEE. The MEE fluids were found to contain C3 splitting factors as demonstrated by their high capacity to convert C3 in vitro from fresh normal human serum. This activity was not inhibited by the classic complement pathway inhibitor, 0.01M ethylene glycol tetra-acetic acid with 0.005M magnesium chloride. The results suggest that a strong local complement activation has taken place and that the factors responsible are present in the MEE of patients with SOM.

Antigen-Antibody Complex↗

PubMed2001

Complement activation in patients with rheumatoid arthritis mediated in part by C-reactive protein.

OBJECTIVE: Complement activation in patients with rheumatoid arthritis (RA) is considered to be triggered by immune complexes. Recently, it was shown that C-reactive protein (CRP) can activate the complement system in vivo. We therefore hypothesized that part of the complement activation in RA is due to CRP. The aim of this study was to investigate CRP-mediated complement activation in RA, and to assess its correlation with disease activity. METHODS: Complexes between CRP and the activated complement components C3d (C3d-CRP) and C4d (C4d-CRP), which reflect CRP-mediated complement activation, as well as the overall levels of activated C3 and C4 were measured in the plasma of 107 patients with active RA and 177 patients with inactive RA. Inactive RA was defined according to the American College of Rheumatology criteria for clinical remission. Disease activity was assessed by the modified Disease Activity Score (DAS28). RESULTS: Plasma levels of C3d-CRP and C4d-CRP were increased in the majority of the patients, and were significantly higher in patients with active disease versus those with inactive RA (P < 0.001). In patients with active RA, the plasma concentrations of C3d-CRP and C4d-CRP correlated significantly with the DAS28 (Spearman's rho 0.61 and 0.55, respectively; P < 0.001), whereas these correlations were less pronounced in patients with inactive RA (Spearman's rho 0.28 [P < 0.001] and 0.25 [P = 0.001], respectively). Levels of activated C3 and C4 were also increased in the majority of the patients, particularly in patients with active RA. CONCLUSION: Part of the activation of complement in RA is mediated by CRP and is correlated with disease activity. We suggest that this activation is involved in the pathogenesis of RA.

Adolescent↗

PubMed2005

Complement inhibition abrogates nerve terminal injury in Miller Fisher syndrome.

A large body of clinical and experimental data indicate that complement activation is an important mechanism for neuronal and glial injury in Guillain-Barré syndromes. Inhibition of complement activation therefore might be expected to limit the progression of the disease. Using in vitro and in vivo models of the Guillain-Barré syndrome variant, Miller Fisher syndrome, we have shown previously that anti-GQ1b ganglioside antibodies target the presynaptic motor nerve terminal axon and surrounding perisynaptic Schwann cells, thereby mediating destructive injury through deposition of membrane attack complex. Here, we have used this model to investigate the effects of a novel therapeutic inhibitor of complement activation, APT070 (Mirococept), both in vitro and in vivo. In these models, APT070 completely prevents membrane attack complex formation, and thereby has a major neuroprotective effect at the nerve terminal, as assessed by immunohistology of perisynaptic Schwann cell and axonal integrity. These data provide a rationale for considering clinical trials of APT070 in Guillain-Barré syndrome, its variant forms, and other complement dependent neuromuscular disorders.

Animals↗

PubMed1983

Relationship of clinical findings in systemic lupus erythematosus to seroreactivity.

We have characterized 52 consecutive patients fulfilling 4 or more of the American Rheumatism Association criteria for systemic lupus erythematosus in order to provide, for the first time, a homogeneous sample for statistical comparison of antinuclear antibody (ANA)-positive and ANA-negative groups. Ten patients (19%) were seronegative. There was no significant difference in age, disease activity, organ system involvement, erythrocyte sedimentation rate, immune complex levels, or C3 levels. The ANA-negative group showed a higher incidence of involvement for whites and men. Leukopenia, lower levels of antibody to DNA, and higher C4 levels were also characteristic of the ANA-negative group.

Adult↗

PubMed1987

Inhibition of interleukin 3 function by a fragment of the third component of complement.

A C3d-like (C3d-1) fragment of 33 kDa was isolated and its biological activity studied. The fragment was generated from guinea pig C3b by porcine pancreas kallikrein and purified by fast protein liquid chromatography. The C3d-like fragment inhibited interleukin (IL) 2-dependent T lymphocyte proliferation. The suppressive activity of the described C3d-1 fragment was not restricted to lymphocytes as targets but inhibited in addition the proliferation of a nonlymphocyte mast cell line which was strictly IL3-dependent in its proliferative capacity. Kinetic studies implied early stages of cellular proliferation to be influenced. Furthermore, the C3d-1 fragment was not only an inhibitor of cellular proliferation but was also a potent inducer of leukocytosis.

Animals↗

PubMed1990

Expression of complement alternative pathway proteins by endothelial cells. Differential regulation by interleukin 1 and glucocorticoids.

We have studied the secretion of proteins of the alternative pathway of complement C3, factor B and factor H by human umbilical vein endothelial cells (HUVEC). Results showed that factor H and factor B are quantitatively secreted in abundance whereas C3 could only be detected when the cells are maintained in culture during long periods of time. Interferon-gamma stimulated factor H, factor B and, to a lesser extent, C3 secretions. Interleukin (IL) 1 had a differential effect on spontaneous C3, factor B and factor H secretions. In the presence of IL 1, there was a significant secretion of C3 occurring within a short period of culture. IL 1 also stimulated factor B secretion. There was a synergistic stimulating effect between IL 1 and interferon-gamma to bring C3 and factor B productions by HUVEC to very high levels. In contrast, factor H secretion was consistently inhibited by IL 1. Local increase in C3 and factor B secretions by endothelial cells in the presence of IL 1 may have important implications in the inflammatory reaction. In striking contrast, the glucocorticoid dexamethasone (DXM) had modulatory effects which are consistent with its anti-inflammatory properties. DXM, at therapeutic concentrations, decreased C3 and factor B secretions and increased factor H secretion. Local modulation of complement protein secretion by DXM appears to be a new mechanism by which this glucocorticoid may control inflammation.

Complement C3b Inactivator Proteins↗

PubMed1994

Impact of long-term hemodialysis on nutritional status in patients with end-stage renal failure.

We evaluated the way in which duration of hemodialysis treatment affects nutritional status in 96 end-stage renal failure patients. According to the length of previous hemodialysis treatment patients were divided into the groups: onset hemodialysis (ON-HD), early-stage hemodialysis (ES-HD, 1-8 months), mid-stage hemodialysis (MS-HD, 9-69 months), and advanced-stage hemodialysis (AS-HD, 70-207 months). Nutritional status was assessed by laboratory data (serum proteins, total lymphocyte count), intradermal skin antigen testing, anthropometric measurements (body mass index [BMI], infrared interactance), and records of food intake. ON-HD patients on a low-protein diet exhibited abnormally low values for serum total protein, albumin, transferrin, and total lymphocyte count and a high prevalence of anergy to skin antigens (69%). In the ES-HD and MS-HD groups values for serum proteins and total lymphocyte count were in the normal range and significantly higher than in ON-HD patients. In addition, a lower proportion of cutaneous anergy was observed (50% and 27%, respectively). Long-term hemodialysis therapy for 6-17 years (AS-HD) was associated with normal levels for all measured serum proteins. Subnormal levels of total lymphocyte count, significantly lower than in MS-HD patients, were associated with an increase in anergy to skin antigens (46%). Serum prealbumin, complement C3c, BMI, body fat, and lean body mass exhibited normal values in all patients and showed no differences between groups. These results indicate that diminished visceral protein stores, lymphopenia, and anergy to skin antigens are widespread in undialyzed uremic patients with end-stage renal failure but become uncommon after the initiation of regular hemodialysis therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1982

Determination of the half-life of C3 in patients and its relation to the presence of C3-breakdown products and/or circulating immune complexes.

Measurement of complement components in serum may not accurately assess the degree of activation of the complement system. An alternative approach is the measurement of conversion products of the complement components. The relation between the presence of an increased concentration of C3-conversion products and the metabolism of C3 was investigated. In a group of patients, circulating immune complexes were also measured (Clq-binding test) to see whether the combination of those markers yielded information on the C3 metabolism. In this study it is shown that static measurements of serum C3 levels is of no value for the degree of complement activation. Measurement of C3-conversion products may indicate C3 hypercatabolism (in 8 of the 11 patients with C3-conversion products), but it does not imply depressed C3 synthesis. Detection of circulating immune complexes by the C1q-binding assay did not always indicate a C3 hypercatabolism. Of 12 SLE patients studied, in 9 of them, a C3 hypercatabolism was detected, and 5 of these patients were clinically characterized by the presence of minor disease symptoms. Overall, the results indicated that detection of circulating immune complexes and/or C3-conversion products could not be used as an absolute measure for insight into the C3 metabolism.

Antigen-Antibody Complex↗