No abstract

A high prevalence of antibodies to the hepatitis C virus (anti-HCV) has been demonstrated among patients with alcoholic liver disease, whereas the prevalence of HCV viremia in these patients remains uncertain. The aims of this study were to determine the prevalence of anti-HCV in alcoholic patients both with and without clinically apparent liver disease and to determine the presence of HCV RNA in those patients who tested positive for anti-HCV by RIBA II (Chiron Corporation, Emeryville, CA). One hundred male patients consecutively admitted to an alcoholic rehabilitation program were included. Group 1 was comprised of 40 patients with clinically apparent liver disease. Group 2 was comprised of 60 patients without clinically apparent liver disease. Anti-HCV was performed by a second-generation ELISA assay and confirmed by RIBA II. HCV RNA was performed by Quantiplex assay (Chiron Corporation) and a nested reverse transcriptase-polymerase chain reaction. No significant differences were found between the two groups with regards to age, quantity and duration of alcohol intake, or accepted risk factors for HCV. The overall prevalence of anti-HCV in our patients was 23%, with 43% of these in group 1 and 10% in group 2. HCV RNA tested positive in 94% of the anti-HCV-positive patients in group 1 and in 67% of the anti-HCV-positive patients in group 2. These data suggest that HCV infection is an important cofactor in the pathogenesis of liver disease among alcoholic patients.

Thrombocytopenia is a frequent clinical finding in patients with hepatitis C virus (HCV) infection. Platelets from patients with HCV infection have been identified as carriers of HCV RNA in our previous studies. The present study was designed to further investigate the possibility of HCV replication in megakaryoblasts from which platelets are eventually released. A megakaryoblastic cell line (MEG-01), established from a chronic myelogenous leukaemia patient 13 years ago, was used for this study. The MEG-01 cells were inoculated with fresh serum from a patient with HCV infection and renamed MEG-01-I cells. Surprisingly, both MEG-01 and MEG-01-I were positive by HCV reverse transcription-polymerase chain reaction (RT-PCR) for the existence of HCV RNA and minus-strand HCV RNA, regardless of inoculation. This was further confirmed by in situ RT-PCR. The HCV antigens, such as core, envelope, and non-structural (NS)3 and NS4, were also present in both cell lines, as identified by Western blotting and indirect immunofluorescence staining. In addition, virus-like particles were observed by electron microscopy in the MEG-01 cell line as well as in the MEG-01-I cell line. These findings indicate that the megakaryoblasts are vulnerable to HCV infection and that replication of HCV can occur in these cells. This may help us to better understand the pathogenesis of thrombocytopenia in patients with HCV infection. The MEG-01 cell line, which may have been continuously shedding HCV for years, should be a useful model for experimental research into HCV.

Sequencing of the hepatitis C virus (HCV) has provided a better understanding of the natural history, immunology, and epidemiology of this virus. However, the morphology of HCV has not been definitively characterized. In this study, through a sequence of concentration processes, virus-like particles were isolated from human serum and liver tissue, visualized by transmission electron microscopy and identified as hepatitis C virion by immunoelectron microscopy. Spherical flavi-like virus particles, approximately 70 nm in diameter, were observed in the fraction with 1.04-1.12 g ml-1 sucrose density and bound to immunogold particles with monoclonal antibodies (mAb) against hepatitis C. The nucleocapsid of the particles, which were 50 nm in diameter, appeared to be icosahedral in structure and surrounded by an envelope covered with surface projections. A 'tadpole' form of particles was also observed. The findings indicate that the low buoyant density in sucrose and the morphological features of the hepatitis C virion are consistent with the characteristics of flaviviruses and pestiviruses.