Search results for "Complement C4b"
showing 7 items of 7 documents
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…
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.…
A NEW PCR-BASED TYPING OF THE RODGERS AND CHIDO ANTIGENIC DETERMINANTS OF THE FOURTH COMPONENT OF HUMAN COMPLEMEMT
1994
The Rodgers (Rg) and Chido (Ch) blood groups are antigenic determinants of the fourth component of human complement C4. They are associated with the two isotypes of C4, C4A and C4B, respectively. They serve as markers to distinguish C4A from C4B as well as for the definition of subtypes of common and rare allotypes. As an alternative to the serological typing method using human alloantisera, a PCR typing procedure with sequence-specific primers (PCR-SSP) was designed. The method was tested on selected DNA samples from individuals with well-defined C4 allotypes. No false-positive or false-negative typing results were obtained and all the determinant combinations could be distinguished. The P…
C4BPB/C4BPA is a new susceptibility locus for venous thrombosis with unknown protein S-independent mechanism: results from genome-wide association an…
2010
3 Figures. 2 Tables. The online version of this article contains a data supplement.
Investigation of Complement Activation Product C4d as a Diagnostic and Prognostic Biomarker for Lung Cancer
2013
[EN] Background There is a medical need for diagnostic biomarkers in lung cancer. We evaluated the diagnostic performance of complement activation fragments. Methods We assessed complement activation in four bronchial epithelial and seven lung cancer cell lines. C4d, a degradation product of complement activation, was determined in 90 primary lung tumors; bronchoalveolar lavage supernatants from patients with lung cancer (n = 50) and nonmalignant respiratory diseases (n = 22); and plasma samples from advanced (n = 50) and early lung cancer patients (n = 84) subjects with inflammatory lung diseases (n = 133), and asymptomatic individuals enrolled in a lung cancer computed tomography screenin…
Complement activation product C4d in oral and oropharyngeal squamous cell carcinoma
2015
OBJECTIVE: Complement C4d-containing fragments have been proposed as diagnostic markers for lung cancer. The purpose of this study was to evaluate the presence of C4d in oropharyngeal (OPSCC) and oral (OSCC) squamous cell carcinomas. SUBJECTS AND METHODS: C4d staining was analyzed by immunohistochemistry in 244 OPSCC surgical specimens. C4d levels were quantified by ELISA in resting saliva samples from 48 patients with oral leukoplakia and 62 with OSCC. Plasma samples from 21 patients with leukoplakia and 30 with oral carcinoma were also studied. RESULTS: C4d staining in OPSCC specimens was associated with nodal invasion (P = 0.001), histopathologic grade (P = 0.014), disease stage (P = 0.0…
Null alleles of human complement C4. Evidence for pseudogenes at the C4A locus and for gene conversion at the C4B locus
1990
The two genes for the C4A and C4B isotypes of the fourth component of human complement are located in the MHC class III region. Previous studies have demonstrated the unusual expression of C4 genes in the form of aberrant or duplicated haplotypes. Null alleles of C4A or C4B (AQ0 or BQ0) have been defined by the absence of gene products and occur at frequencies of 0.1-0.3. However, only some C4 null alleles are due to gene deletions, the remainder were thought to be nonexpressed genes. We have analyzed the C4 gene structure of 26 individuals lacking either C4A or C4B protein. The DNA of individuals with apparently nonexpressed C4 genes was tested for the presence of C4A- and C4B-specific seq…