Search results for "Complement C4"
showing 10 items of 38 documents
Association between Leptin and Complement in Hepatitis C Patients with Viral Clearance: Homeostasis of Metabolism and Immunity
2016
Background The association between leptin and complement in hepatitis C virus (HCV) infection remains unknown. Methods A prospective study was conducted including 474 (250 genotype 1, 224 genotype 2) consecutive chronic hepatitis C (CHC) patients who had completed an anti-HCV therapy course and undergone pre-therapy and 24-week post-therapy assessments of interferon λ3-rs12979860 and HCV RNA/genotypes, anthropometric measurements, metabolic and liver profiles, and complement component 3 (C3), C4, and leptin levels. Results Of the 474 patients, 395 had a sustained virological response (SVR). Pre-therapy leptin levels did not differ between patients with and without an SVR. Univariate and mul…
Shortened Activated Partial Thromboplastin Time May Help in Diagnosing Hereditary and Acquired Angioedema
2016
<b><i>Objective:</i></b> To evaluate whether activated partial thromboplastin time (APTT) could be used in the laboratory diagnosis of hereditary or acquired angioedema (HAE or AAE) with and without C1 inhibitor (C1-INH) deficiency. <b><i>Methods:</i></b> In a prospective investigation, APTT and other coagulation parameters were determined in 149 adult patients with various types of angioedema and in 26 healthy participants (HP). <b><i>Results:</i></b> Mean APTT was significantly shortened in HAE-C1-INH type I (p < 0.0001) and type II (p = 0.0017) and in AAE-C1-INH (p < 0.0001) compared to the HP. APTT was shorten…
C4BQ0: a genetic marker of familial HCV-related liver cirrhosis
2004
Source Department of Medicine and Pneumology, V Cervello Hospital, Via Trabucco 180, 90146 Palermo, Italy. lindpas@yahoo.it Abstract BACKGROUND AND METHODS: Host may have a role in the evolution of chronic HCV liver disease. We performed two cross-sectional prospective studies to evaluate the prevalence of cirrhosis in first degree relatives of patients with cirrhosis and the role of two major histocompatibility complex class III alleles BF and C4 versus HCV as risk factors for familial clustering. FINDINGS: Ninety-three (18.6%) of 500 patients with cirrhosis had at least one cirrhotic first degree relative as compared to 13 (2.6%) of 500 controls, (OR 7.38; CI 4.21-12.9). C4BQ0 was signifi…
C4, BF, C3 Allele Distribution and Complement Activity in Healthy Aged People and Centenarians
1999
The aim of this study was to examine the complement system and the distribution of some human leukocyte antigen (HLA) class III alleles (C4, BF) in healthy aged people (77 centenarians and 89 elderly subjects). We have also studied the alleles of C3, a complement component genetically unrelated to HLA, the immunochemical levels of C4 and C3 and serum functional hemolytic activity for classical (CH50) and alternative (AP50) complement pathway. The levels of C3 and C4 and the CH50 and AP50 were found to be within the normal range. The frequencies of C3, BF, and C4A alleles were similar in the cohorts that have been studied. For C4B null allele (C4BQ0) a trend toward an increase in the older c…
C4A deficiency and nonresponse to hepatitis B vaccination
2002
Hepatitis B vaccination failure has been linked to the presence of certain human leukocyte antigen class II alleles. However, the functional background of these associations has remained unclear. Complement component C 4 is encoded within the major histocompatibility complex and is essential for classical pathway activation.Healthy individuals (n=4269) were vaccinated in a prospective trial with Engerix B. Nonresponse was classified as anti-HBs10 U/l after the last vaccination. Seventy-three nonresponders (NR) (1.7%) were identified. For comparison 53 responders (R) (anti-HBs10 IU/l) were drawn randomly from the same cohort. C4 allotyping was carried out by high-voltage agarose gel electrop…
Pathogenesis of autoimmune diseases associated with 8.1 ancestral haplotype: a genetically determined defect of C4 influences immunological parameter…
2003
Abstract Subjects with certain HLA alleles have a higher risk of specific autoimmune diseases than those without these alleles. The 8.1 ancestral haplotype (AH) is a common Caucasoid haplotype carried by most people who type for HLA-B8,DR3. It is unique in its association with a wide range of immunopathological diseases. To gain insight into the identification of the mechanism(s) of disease susceptibility of 8.1 AH carriers, we have investigated the prevalence of circulating immune complexes and non-organ-specific autoantibodies in healthy carriers of the haplotype. The results show that carriers of 8.1 AH display both a significant increased prevalence of immune complexes and higher titers…
Characterization of non-expressed C4 genes in a case of complete C4 deficiency: identification of a novel point mutation leading to a premature stop …
1998
The genetic basis of complete C4 deficiency in a patient with SLE was investigated. Previous studies have demonstrated that this patient has two different major histocompatibility complex (MHC) haplotypes that each contain a major deletion and a non-expressed C4 gene. In the present study, non-expression of the C4 genes was explained by the finding of two distinct C4 gene mutations. A previously described two base pair insertion in exon 29 of the C4 gene was detected in the paternal MHC haplotype [HLA-A2, B40, SC00, DR6]. The maternal haplotype [HLA-A30, B18, F1C00, DR3] carried a C4 gene with a one base pair deletion in exon 20 generating a premature stop codon. This mutation was neither f…
Immunonephelometric determination of the C4b-binding protein.
1993
A fully mechanised immunonephelometric method for the rapid and specific determination of C4b-binding protein (C4b-BP) in citrated plasma is described. The method utilizes commercially available rabbit antiserum against human C4b-BP and a nephelometer analyser. A single determination can be performed within 6 min, requiring 80 microliters sample volume. The measuring range is about 10 to 200% of normal C4b-BP. Precision is characterized by intraassay coefficients of variation between 1.5% and 2.8%, and interassay coefficients of variation between 4.0% and 4.6% for the same C4b-BP concentrations. The nephelometry of C4b-BP was correlated with electroimmunodiffusion (Laurell technique; r = 0.…
Are laboratory tests useful for monitoring the activity of lupus nephritis? A 6-year prospective study in a cohort of 228 patients with lupus nephrit…
2008
Objectives:To evaluate the role of immunological tests for monitoring lupus nephritis (LN) activity.Methods:C3, C4, anti-dsDNA and anti-C1q antibodies were prospectively performed over 6 years in 228 patients with LN.Results:In membranous LN only anti-C1q antibodies differentiated proteinuric flares from quiescent disease (p = 0.02). However, in this group 46% of flares occurred with a normal value of anti-C1q antibodies versus 20% in proliferative LN (p = 0.02). In patients with antiphospholipid antibodies (APL), 33% of flares occurred with normal levels of anti-C1q antibodies versus 14.5% in patients that were APL-negative (p = 0.02). In proliferative LN, anti-C1q antibodies showed a slig…
Hereditary angioedema with normal C1-inhibitor activity in women.
2000
Summary Background Hereditary angioedema (HAE) is a well defined autosomal dominant disease (Mendelian Inheritance in Man #106100) that results from an inherited deficiency of C1 (the activated first component of complement) inhibitor function. We report an unusual variant of HAE with normal biochemical C1-inhibitor function, occurring only in women. Methods We screened 574 patients with recurrent angioedema of the skin for presence of HAE. 283 patients were selected, in whom angioedema was associated with abdominal pain attacks or recurrent life-threatening episodes of upper-airway obstruction, or both, rather than with urticaria. We measured C1-inhibitor concentration and functional activ…