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PubMed1986

Serum sickness and haematopoietic recovery with antithymocyte globulin in bone marrow failure patients.

We have evaluated 33 patients with various bone marrow dyscrasias treated with horse antithymocyte globulin (ATG) (Upjohn) to determine the relationship of haematopoietic response to the occurrence of serum sickness. Patients received ATG intravenously over 10 or 28 d at a dose of 15 mg/kg/d. Total or partial haematological responses were noted in 12 of 33 patients. Twenty-eight patients developed clinical signs of serum sickness 6-14 d after the first infusion of ATG, while five patients did not. Twenty-five of these patients were evaluated by immunochemical assays for circulating immune complexes (C1q-binding assay) and 21 patients for serum complement (C3, C4 and CH50 assay) levels. There was a direct correlation between increases in immune complex levels, decreases in serum complement levels, and the development of the clinical signs and symptoms and serum sickness. Twenty-one of 28 patients who developed serum sickness failed to show haematological improvement. However, haematopoietic recovery occurred in all five patients who did not manifest serum sickness (P less than 0.05) and in four patients who failed to develop immune complexes. These findings indicate that the development of serum sickness is not required for a haematopoietic response with ATG and may indeed impair recovery.

Adolescent↗

PubMed1990

[Blood endotoxin in acute pancreatitis using limulus amebocyte lysate test (LAL test)].

Forty-five cases of acute pancreatitis observed during the period 1986-88 were included in this study. Four of the 45 patients were operated during the acute phase and of these, two died. The remaining 41 patients were treated with conservative therapy using the application of a nasogastric tube, analgesics, and the endovenous administration of various solutions and antibiotics. The severity of each attack of pancreatitis was assessed according to Ranson and Agarwal's criteria. In severe cases (more than 3 of Ranson's criteria) the presence of endotoxin in the systemic circulation was shown using the "limulus" method, together with contemporary low levels of C3 complement factor. As is evident from the results of the study, the presence of endotoxinemia and the low level of C3 in acute pancreatitis are related to the high percentage of complications.

Acute Disease↗

PubMed1995

Immunologic & pulmonary function abnormalities in tropical pulmonary eosinophilia.

Twenty six patients (24 males and 2 females) with tropical pulmonary eosinophilia (TPE) were studied. Arterial blood gas analysis, pulmonary functions, peripheral blood examination and bronchoalveolar lavage (BAL) were performed. Peripheral blood and BAL fluid analyses were performed in healthy volunteers. Pulmonary functions revealed a mild restrictive ventilatory defect with airways obstruction. Mild hypoxaemia was observed on arterial blood gas analysis. Serum immunoglobulins IgG (P < 0.01), IgA (P < 0.001) and IgM (P < 0.001) were significantly raised as compared to normal controls. Serum complement (C3) level was higher, however, it was not significantly different as compared to normal controls. Serum haemolytic component of the complement (CH50) was significantly higher (P < 0.001) in patients with TPE compared to normal control subjects. The immunoglobulins IgG, IgA and IgM in the BAL fluid were significantly (P < 0.001) increased as compared to normal controls. The fibronectin (FN) level was also significantly increased (P < 0.001) in the BAL fluid. It is concluded that patients with TPE have mild restrictive ventilatory defect with airways obstruction and mild hypoxaemia. They have eosinophilic alveolitis with increased levels of immunoglobulins in the peripheral blood and BAL fluid. The significance of elevated FN in the BAL fluid is not clear and serial estimations may have to be done in order to clarify its role in the pathogenesis of fibrosis in chronic TPE.

Adolescent↗

PubMed2007

Decay-accelerating factor must bind both components of the complement alternative pathway C3 convertase to mediate efficient decay.

Decay-accelerating factor (DAF; CD55) inhibits the complement (C) cascade by dissociating the multimolecular C3 convertase enzymes central to amplification. We have previously demonstrated using surface plasmon resonance (Biacore International) that DAF mediates decay of the alternative pathway C3 convertase, C3bBb, but not of the inactive proenzyme, C3bB, and have shown that the major site of interaction is with the larger cleavage subunit factor B (Bb) subunit. In this study, we dissect these interactions and demonstrate that the second short consensus repeat (SCR) domain of DAF (SCR2) interacts only with Bb, whereas SCR4 interacts with C3b. Despite earlier studies that found SCR3 to be critical to DAF activity, we find that SCR3 does not directly interact with either subunit. Furthermore, we demonstrate that properdin, a positive regulator of the alternative pathway, does not directly interact with DAF. Extending from studies of binding to decay-accelerating activity, we show that truncated forms of DAF consisting of SCRs 2 and 3 bind the convertase stably via SCR2-Bb interactions but have little functional activity. In contrast, an SCR34 construct mediates decay acceleration, presumably due to SCR4-C3b interactions demonstrated above, because SCR3 alone has no binding or functional effect. We propose that DAF interacts with C3bBb through major sites in SCR2 and SCR4. Binding to Bb via SCR2 increases avidity of binding, concentrating DAF on the active convertase, whereas more transient interactions through SCR4 with C3b directly mediate decay acceleration. These data provide new insights into the mechanisms involved in C3 convertase decay by DAF.

Biological Assay↗

PubMed1998

Cross-linking CD21/CD35 or CD19 increases both B7-1 and B7-2 expression on murine splenic B cells.

Activation of the complement cascade and ligation of complement C3 receptors on B cells represent an important bridge between innate and Ag-specific acquired immunity. We show here that cross-linking of mouse CD21 (complement receptor type 2, CR2, C3d receptor) and CD35 (complement receptor type 1, CR1, C3b/C4b receptor) or co-cross-linking of CD21/CD35 and surface IgM rapidly up-regulates both B7-1 and B7-2 expression on murine resting splenic B cells. CD21/CD35-mediated up-regulation of both B7-1 and B7-2 expression is observed within 14 h, while other stimuli up-regulate only B7-2 but not B7-1 at this early time point. Consistent with the increase in B7 levels, BALB/c B cells on which surface IgM and CD21/CD35 have been co-cross-linked stimulate C57BL/6 T cells more effectively than controls. This CD21/CD35-enhanced allogeneic MLR is blocked nearly completely by anti-B7-2 mAbs and partially by anti-B7-1 mAbs. In addition, cross-linking of CD19, which is physically associated with CD21/CD35, leads to increased B7-1 and B7-2 expression. These data suggest that CD21/CD35 ligation results in enhanced B cell Ag presentation using costimulatory mechanisms shared with other activators and thus works cooperatively in this process. Rapid up-regulation of B7-1 expression, a unique response to CD21/CD35 and CD19 cross-linking, may be a particularly important effect of C3-containing ligands. We propose that CD21/CD35- and CD19-mediated B7-1 and B7-2 up-regulation is an important mechanism by which complement activation links innate and acquired immunity.

Animals↗

PubMed1984

Determination of circulating immune complexes, C3 and C4 complement components and anti-DNA antibody in different classes of lupus nephritis.

Circulating immune complexes (CIC) were measured in 237 sera from children who underwent a renal biopsy during the course of systemic lupus erythematosus. CIC-positive sera contained a lower mean level of C3 but not C4. Anti-DNA antibody was similar in CIC-positive and negative sera. The World Health Organization classification of lupus nephritis was used to categorize the biopsies. CIC, C3, C4 and anti-DNA antibody were determined to assess whether they correlated with the severity of renal lesions. Of 25 sera obtained at renal biopsy from patients with classes 2, 3 and 4, 16 were positive for CIC. C3 was significantly lower in classes 3 and 4 than in class 2. C4 was reduced and anti-DNA antibody was present in classes 2, 3 and 4. Determination of the level of C3 but not C4, CIC or anti-DNA antibody correlates with the severity of lupus nephritis seen on renal biopsies. Nevertheless, performance of a renal biopsy is preferred.

Antibodies, Anti-Idiotypic↗

PubMed1997

Biosynthesis and secretion of MHC class III gene products (complement C4 and factor B) in the exocrine pancreas.

We recently found that complement C3 is locally synthesized and secreted into the exocrine pancreas. In the present study, we attempted to demonstrate the secretion of complement C4 and factor B in the exocrine pancreas. In five samples of pancreatic fluid, both C4 and factor B proteins were detected by enzyme-linked immunosorbent assay (ELISA). Immunoblot analysis revealed the C4 and factor B molecules in pancreatic fluid to be identical with these molecules in serum. Reverse transcriptase (RT)-polymerase chain reaction (PCR) analysis in pancreatic carcinoma cell lines suggested ductal epithelial cells to be the local production sites of these proteins in the pancreas. The secretion of C4 and factor B in ductal cell lines (PANC-1 and MIA PaCa-2) was independently regulated by interleukin (IL)-1 beta, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma; C4 secretion was induced by IFN-gamma, whereas factor B secretion was induced by IL-1 beta, TNF-alpha, or IFN-gamma. These observations indicate that: (a) complement C4 and factor B are secreted into the exocrine pancreas, (b) ductal epithelial cells appear to be the site of C4 and factor B biosynthesis, and (c) local secretion of C4 and factor B in the pancreas is differentially regulated by IL-1 beta, TNF-alpha, and IFN-gamma.

Adult↗

PubMed2003

Isolation and characterization of anticomplementary beta-glucans from the shoots of bamboo Phyllostachys edulis.

Bamboo, Phyllostachys edulis produces well known edible shoots in Asia. Immunostimulating anticomplementary (complement activating) substances have been recognized as a characteristic biological response modifier (BRM). In the present study, we isolated and characterized three anticomplementary beta-glucans (BS-BGA, BS-BGB, and BS-BGC) from bamboo shoots. Hot-water extraction, DEAE-Toyopearl 650M-column chromatography, amylase digestion and concanavalin A adsorption, and Sephacryl S-100 HR column chromatography were applied to isolate the beta-glucans. The average molecular masses of the beta-glucans were estimated to be from 14,500 to 85,300 Da by HPSEC-MALLS-RI. All three beta-glucans (0.1-1.0 mg/mL) activated the complement system via the alternative pathway, and could cleave human complement C3 under Ca 2+-free gelatin veronal buffered saline. Among them, the largest molecule, BS-BGA was the most potent complement activator. Methylation analysis and NMR spectroscopy were used to achieve their structural characterization. They are all water-soluble and composed mainly of backbone structures of beta-(1-->3)-glucan with beta-(1-->4)-linked side chains varying in degree of branching. BS-BGA consisted of a higher proportion of 3-linked glucopyranosyl residues and a lower degree of branching than BS-BGB and BS-BGC. In particular, BS-BGA contained a small amount of O-acetyl groups at C-6 of the 3-linked glucopyranosyl residues. These data demonstrate that the structural characteristics including molecular size, degree of branching, and O-acetyl substitution are involved, at least in part, in their different anticomplementary activities.

Complement Inactivator Proteins↗

PubMed2000

Oral mucosal conditions and some related factors in 140 Uygur centenarians.

OBJECTIVE: To investigate the condition of the oral mucosae in Xinjiang Uygur centenarians and explore some related factors. METHODS: The oral mucosae and mucosal exfoliative cells of 140 Xinjiang Uygur centenarians were examined. Saliva and blood were collected from some centenarians. Salivary immunoglobulins (IgA, IgM, IgG), complements (C3 and C4), nitrous oxide (NO), 10 trace elements, serum sex hormones, thyroid hormones and osteocalcin (OST) were analysed using immunoglobulin, complement and NO kits, an ionochromatophotometer, and the kits for sex hormones and thyroid hormones, and fluorescence enzyme-linked immunosorbent assay, respectively. RESULTS: Most centenarians (64.29%) had normal labial, buccal, palatal and gingival mucosae. The abnormal changes in mucosae were mainly vascular nevus patches and senile plaques. Their mucosal exfoliative cells showed similar characteristics to those in elderly Han. The centenarians who had normal mucosae had higher level of the trace element molybdenum (Mo) in their saliva than who had abnormal mucosae (P < 0.01). CONCLUSION: The oral mucosal condition of Uygur centenarians was generally good. The abnormal changes in oral mucosae of the centenarians were lesions not harmful to health and may be related to the lower level of Mo in their saliva.

Aged↗

PubMed1975

DNA-antibodies in sera from patients with systemic lupus erythematosus.

DNA-antibody determinations using the Farr technique and LE cell tests were performed on single serum samples from 55 patients with SLE according to well defined criteria. It was found that the DNA-antibody test was just as sensitive as the LE cell test, and studies of sera from patients with questionable SLE, discoid LE, other connective-tissue diseases, psoriasis, and from healthy persons, indicated that the DNA-antibody test is highly specific for SLE. Neither the DNA-antibody test nor the LE cell test could discriminate between SLE patients with active and inactive disease as estimated by clinical criteria or by the serum concentrations of complement C3 and C4.

Antibodies, Antinuclear↗

PubMed1974

Metabolic studies of the third component of complement and the glycine-rich beta glycoprotein in patients with hypocomplementemia.

Metabolic studies using radioiodine-labeled third component of complement (C3) and the glycine-rich beta glycoprotein (GBG), a major component of the C3b-feedback pathway, were undertaken in normal subjects, in 22 patients with evidence of complement activation, and in 11 patients with various renal diseases without evidence of complement activation. In seven normal subjects GBG was found to be a rapidly metabolized protein with catabolic rates ranging from 1.7% to 2.2% of the plasma pool/h, synthesis rates from 0.14 to 0.21 mg/kg per h. and extravascular/intravascular distribution ratios from 0.81 to 1.31. In patients with reduced plasma C3, both increased C3 fractional catabolic rates and reduced C3 synthesis rates were observed, and in some patients there was evidence of increased extravascular distribution of the protein. GBG catabolism was usually increased when there was evidence of C3 activation, presumably reflecting activation of the C3b-feedback; but GBG turnover was normal or only slightly accelerated in some patients with accelerated C3 catabolism and profound hypocomplementemia, suggesting that reduced C3 synthesis had limited activation of the C3b-feedback.

Complement Inactivator Proteins↗

PubMed1975

In vitro synthesis of some complement components (C1q, C3 and C4) by lymphoid tissues and circulating leucocytes in man.

Human lymphoid tissues and peripheral blood leucocytes and monocytes were studies with respect to the synthesis of complement components (C1q, C3 and C4) using an in vitro culture technique. All of the lymphoid tissues investigated (bone marrow, thymus, lymph node, spleen, tonsil, adenoid) synthesize complement components in different patterns. C3 was produced by all lymphoid tissues except the spleen, which was the only lymphoid tissue in which C4 production was regularly found. C1q synthesis was demonstrated in the spleen and adenoid cultures, and occasionally also in those of lymph node tissue. Lymphocytes in peripheral blood from normal individuals and in thoracic duct lymph, and also from patients suffering from chronic lymphatic leukaemia, do not synthesize any of these complement components. Peripheral blood leucocyte samples from normal individuals, containing 60 per cent lymphocytes and 40 per cent monocytes, do synthesize C3, however. Separation of the monocytes from these samples showed that it was in these cells that the synthesis of C3 occurred. Production of C3 by mononuclear phagocytes is also supported by the finding that peripheral blood leucocytes from patients suffering from acute monocytic leukaemia synthesize C3. C1q and C4 synthesis could not be demonstrated in any of the cultures of circulating leucocytes.

Adenoids↗

PubMed1979

[Detection of receptors for the IgG Fc fragment as well as for the C3 component of complement in the spleen T-lymphocytes of CBA mice].

The presence of receptors to the Fc fragment of IgG and to the C3 component in the complement of T lymphocytes in the spleen of CBA mice was studied. The study was made by the method based on Coons's indirect immunofluorescence test with the use of antithymocytic globulin, in combination with EA and EAC rossette-formation. A significant percentage of T lymphocytes was found to have the receptor to the Fc fragment of IgG, while only a small part of T lymphocytes was found to have the receptor to the C3 component of the complement.

Animals↗

PubMed1973

A new complement-mediated cytolytic mechanism--the C1-bypass activation pathway.

A new cytolytic pathway is described whereby cells sensitized with cytotoxic antibody can be specifically lysed in the complete absence of intact, classical complement pathway function. Evaluation of this model with sera deficient in the 4th (C4), 2nd (C2), and 6th (C6) components of complement has revealed that this new lytic mechanism, termed the C1-bypass activation pathway, is initiated by the antibody-mediated activation of C1. Utilizing components of the previously described alternate complement pathway, this pathway bypasses C4 and C2 to activate the third to ninth components of complement (C3-9) with induction of membrane damage.

Animals↗

PubMed1969

Anaphylatoxin release from the third component of human complement by hydroxylamine.

Treatment of highly purified preparations of the third component of complement (C3) with 0.5M hydroxylamine at 20 degrees C for 15 to 30 minutes, followed by acidification, resulted in dissociation of a peptide from the C3 molecule. The isolated fragment (molecular weight, 7600) resembled enzymatically liberated anaphylatoxin (C3a) with respect to size, charge, amino acid composition, and biological activity. Its capacity to contract smooth muscle was inhibitable by antihistamines; it also produced tachyphylaxis and desensitization of the guinea pig ileum to C3a. Thus native C3 probably contains an esterlike bond and hydroxylamine-liberated anaphylatoxin may represent one of the polypeptide chains of the C3 molecule.

Amino Acids↗

PubMed1989

Identification of plasma proteins adsorbed to hemodialyzers during clinical use.

An investigation has been made of the protein layers formed on hemodialysis membranes during clinical use. Dialyzers having membranes of polymethylmethacrylate (PMMA), Cuprophane, cellulose acetate (CA), and saponified cellulose ester (SCE) were examined. Immediately following dialysis the dialyzers were washed free of blood and the membranes eluted with 2% SDS. The eluates were examined by SDS-PAGE followed by protein immunoblotting. Antisera to 16 common plasma proteins were used to probe for the presence of these proteins in the eluates. Most of the proteins tested for were found in the different eluates, suggesting that the protein layers are extremely complex. The protein compositions were qualitatively different on the different membranes. Except for HMWK the contact phase clotting factors were present in very small amounts and were largely activated. The clear presence of HMWK and the relatively small amounts of fibrinogen provide support for the occurrence of the Vroman effect. Fibrinogen was found to be degraded and this may be related to the observation that plasminogen was activated to plasmin. Complement C3 was an abundant component of all eluates. It was degraded to small fragments in a way which could not be related to complement activation. Many of the other proteins, particularly those of high molecular weight, were extensively degraded. It is speculated that this heretofore unremarked phenomenon may be due to the action of enzymes released by cell damage.

Absorption↗

PubMed1984

Lack of effect of tranexamic acid on rheumatoid arthritis.

In a double-blind controlled study on 45 rheumatoid arthritis patients, no effect of tranexamic acid (Cyklocapron, 4.5 g per day for 6 weeks) was found in terms of subjective or objective parameters of disease activity. Tranexamic acid did not reduce complement activation, measured by plasma concentrations of the complement C3 split product C3d. Immune complex concentrations in serum were also unaffected. We conclude that plasmin inhibitors do not reduce immune complex mediated complement activation, and they should not be used for treatment of rheumatoid arthritis.

Adult↗

PubMed1975

Hereditary complement (C2) deficiency with dermatomyositis.

A 60 year old white man in previous good health presented with a 6 month history of progressive muscle weakness. Clinical and laboratory findings were typical of dermatomyositis. Muscle biopsy confirmed the presence of inflammatory myopathy; deposits of immunoglobulin G (IgG), immunoglobulin M (IgM) or third component of complement (C3) were not detected by immunofluorescence. No evidence was found for an associated neoplasm. An unexpected finding was the total absence of serum hemolytic complement activity. Further investigation revealed that the complement defect was attributable to a selective and total absence of the second component of complement (C2), as determined by both functional and immunoprecipitin assays. Family studies indicated that the defect was inherited in an autosomal recessive manner, as has been observed in the previously reported C2-deficient kindreds. This case demonstrates that typical muscle lesions of dermatomyositis can occur in the presence of a complement defect which would preclude activation of the classic (C1-C4-C2) complement pathway. The case is of further interest as one of a series of recently reported associations of rheumatic diseases with hereditary complement deficiencies. Study of the functional properties of the propositus' C2-deficient serum demonstrated normal generation of chemotactic activity in the presence of endotoxin or aggregated IgG, and normal or near normal bactericidal activity against Salmonella typhi O 901 and Hemophilus influenzae, type b. These findings emphasize the importance of the alternate (properdin) pathway of complement activiation in these functions.

Biopsy↗