Hepatitis C virus (HCV) specific immune responses in anti-HCV positive patients without hepatitis C viraemia.
BACKGROUND/AIMS: Most patients infected with hepatitis C virus (HCV) develop chronic infection and persistent viraemia. The immune mechanisms responsible for resolution of viraemia remain poorly understood. HCV specific humoral and cellular immune responses in patients with and without viraemia were investigated. METHODS: In vitro T helper (TH) lymphocyte responses to structural and non-structural HCV proteins were determined by means of proliferative response and cytokine production in 35 anti-HCV positive/HCV RNA negative patients and in 31 patients with chronic HCV infection and persistent viraemia. Humoral responses were determined by measuring HCV specific antibody quantity and specificity. RESULTS: A TH response to two or more HCV proteins was present in 18 of 35 patients with serological viral clearance compared with just one of 31 viraemic patients (p = 0.00001). HCV specific interferon-gamma production was increased only in the former group. In contrast, the antibody levels were significantly lower and directed at fewer HCV antigens in patients with undetectable HCV RNA. CONCLUSIONS: Patients without viraemia after HCV infection frequently have strong TH lymphocyte responses of the TH1 type to multiple HCV antigens many years after the onset of infection, whereas antibody responses are less marked. These results suggest that control of HCV replication may depend on effective TH lymphocyte activation. (+info)
Oval cell numbers in human chronic liver diseases are directly related to disease severity.
The risk of developing hepatocellular carcinoma is significantly increased in patients with genetic hemochromatosis, alcoholic liver disease, or chronic hepatitis C infection. The precise mechanisms underlying the development of hepatocellular carcinoma in these conditions are not well understood. Stem cells within the liver, termed oval cells, are involved in the pathogenesis of hepatocellular carcinoma in animal models and may be important in the development of hepatocellular carcinoma in human chronic liver diseases. The aims of this study were to determine whether oval cells could be detected in the liver of patients with genetic hemochromatosis, alcoholic liver disease, or chronic hepatitis C, and whether there is a relationship between the severity of the liver disease and the number of oval cells. Oval cells were detected using histology and immunohistochemistry in liver biopsies from patients with genetic hemochromatosis, alcoholic liver disease, or chronic hepatitis C. Oval cells were not observed in normal liver controls. Oval cell numbers increased significantly with the progression of disease severity from mild to severe in each of the diseases studied. We conclude that oval cells are frequently found in subjects with genetic hemochromatosis, alcoholic liver disease, or chronic hepatitis C. There is an association between severity of liver disease and increase in the number of oval cells consistent with the hypothesis that oval cell proliferation is associated with increased risk for development of hepatocellular carcinoma in chronic liver disease. (+info)
Ontogeny of hepatitis C virus (HCV) hypervariable region 1 (HVR1) heterogeneity and HVR1 antibody responses over a 3 year period in a patient infected with HCV type 2b.
Hypervariable region 1 (HVR1) sequences of 96 clones at six time-points representing 27 variants in two major and one minor group were identified in a patient with chronic hepatitis C virus (HCV) infection over 3 years. Major and selected minor variants were used to design synthetic peptides corresponding to the HVR1 C terminus. Peptide ELISA reactivity with IgG was plotted against the corresponding clone frequency, and three patterns emerged: (1) three peptides were unreactive; (2) antibodies against two peptides followed emergence of the corresponding variant, suggesting isolate-specificity; (3) antibodies against four peptides preceded the appearance of the corresponding variant, indicating cross-reactivity or previous exposure. Cross-reactivity was investigated further: sera from six time-points were tested against 11 unrelated HVR1 peptides, seven of which (63.6%) showed cross-reactivity at all time-points. Cross-reactivity of nine patient-specific peptides tested against a panel of 45 heterologous sera from chronic HCV carriers ranged between 0 and 20%. Only three of 27 variants appeared at more than one time-point and in two cases specific and/or cross-reactive HVR1 antibodies coexisted with the corresponding variant, consistent with emergence of escape mutants. In addition, analysis of HVR1 IgG reactivity within a group of closely related patient-specific peptides revealed a loss of reactivity in one peptide attributable to a single amino acid substitution. Interferon-alpha treatment considerably reduced viral RNA but, paradoxically, heterogeneity increased. (+info)
The natural course of hepatitis C virus infection 18 years after an epidemic outbreak of non-A, non-B hepatitis in a plasmapheresis centre.
BACKGROUND: The natural history of hepatitis C virus (HCV) infection is variable and factors determining the course of the illness are unclear. AIMS: To determine the natural course of HCV infection in a well characterised group of patients 18 years after an epidemic outbreak of non-A, non-B hepatitis at a plasmapheresis centre. METHODS: Between 1994 and 1996, 20 of 30 affected individuals were studied. HCV infection was confirmed using second and third generation ELISA test kits. HCV RNA was detected by a polymerase chain reaction (PCR) method and HCV genotyping was performed by analysing amplicons from the conserved 5'-non-translated region generated by nested PCR. Thirty two liver biopsies were carried out in 14 patients. RESULTS: HCV antibodies were detected in all subjects. Eighteen patients had abnormal liver enzymes and 17 were HCV RNA positive, all of whom were infected with genotype 1a. Ninety per cent of this cohort showed evidence of chronic HCV infection with 50% having progressive liver disease and 20% cirrhosis 18 years after acute onset of non-A, non-B hepatitis. Considerable variation in disease outcome occurred between individuals and no correlation with clinical features of the acute illness was found. CONCLUSIONS: Variability in the consequences of HCV infection in cases infected with the same virus suggests that host factors are important in determining disease outcome. The factors which determine differences in the natural history of the disease still remain to be elucidated. (+info)
Differences between hepatitis C virus 5' untranslated region quasispecies in serum and liver.
It is unclear whether the sequence populations of hepatitis C virus (HCV) quasispecies in the liver and in serum are different, as a variety of studies on this subject provide conflicting results. In the current study, the populations of HCV 5' untranslated region (5' UTR) sequences in paired serum and liver samples from six patients with chronic hepatitis were analysed. Liver-derived, negative-strand viral RNA was amplified with a highly strand-specific Tth-based assay, and extensive measures, including accounting for template copy number, were undertaken to lower the risk of sporadic artefactual polymorphism. Amplified sequences were compared by single-strand conformation polymorphism analysis and by direct sequencing of identified differences. In four patients, liver samples were found to contain variants within the quasispecies which were not found in serum or negative-strand viral RNA, while in the remaining two patients, low virus titre prevented a reliable quasispecies analysis. These results suggest the presence in the same individual of HCV variants differing in the 5' UTR and possibly replicating with different kinetics. (+info)
Prevalence and changes in hepatitis C virus genotypes among multitransfused persons with hemophilia. The Multicenter Hemophilia Cohort Study.
The purpose of this study was to determine hepatitis C virus (HCV) genotypes and their relationship to HCV RNA levels over time in a cohort of multitransfused hemophiliacs. Following reverse transcription and polymerase chain reaction amplification of HCV RNA, the product DNAs were genotyped by using the line probe assay. HCV RNA was quantified by the branched-chain DNA assay. Genotyping was done on 109 serum samples from 32 subjects. Genotype 3a had the highest prevalence (41%), followed by genotypes 1a (31%) and 1b (13%). Changes in genotypes were observed in 18 (58%) of the subjects >3-15 years of age. Changes were more common in human immunodeficiency virus (HIV)-positive subjects (13/17) than in HIV-negative subjects (5/15) (P=.014). HCV RNA increased 30-fold in HIV-positive subjects whose genotypes changed. Consensus nucleotide sequencing confirmed genotype changes in 2 patients. We conclude that genotype changes are common in hemophiliacs with chronic HCV, particularly in those who are coinfected with HIV. (+info)
Imbalance of IL-1 beta and IL-1 receptor antagonist mRNA in liver tissue from hepatitis C virus (HCV)-related chronic hepatitis.
Increased levels of IL-1 beta and IL-1 receptor antagonist (IL-1Ra) have been found in serum of patients with chronic liver diseases, although their expression in liver tissue has not been extensively investigated. The aim of this study was therefore to examine the relationship between IL-1 beta and IL-1Ra at tissue level in patients with HCV-related chronic active hepatitis (CAH) of varying degrees of severity. IL-1 beta and IL-1Ra mRNA expression was investigated by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) in 31 patients with CAH of varying severity (classified as minimal/mild in 13 cases and moderate/severe activity in 18 cases) and in 12 control subjects. Quantitative evaluation of IL-1 beta and IL-1Ra corresponding bands was performed by densitometric image analysis, and expressed in arbitrary units. The 12 controls expressed a similar pattern with a mean IL-1 beta/IL-1Ra ratio of 1.03 (1.03 +/- 0.15 (mean +/- s.e.m.), median 0.92, range 0.71-1.45). Minimal/mild activity CAH showed a prevalence of IL-1Ra mRNA expression (1.14 +/- 0.64, median 0.43, range 0-8.75) when compared with controls (0.27 +/- 0.04, median 0.23, range 0.11-0.45) and with moderate/severe activity CAH (0.20 +/- 0.04, median 0.12, range 0-0.67; P = 0.01). Since IL-1 beta expression was similar in the three groups, a significantly different IL-1 beta/IL-1Ra ratio emerged between controls, patients with moderate/severe CAH (2.22 +/- 0.48, median 2.76, range 0-6.12) and those with minimal/mild activity CAH (0.62 +/- 0.15, median 0.5, range 0-1.58, P = 0.005). Patients with higher grades of fibrosis showed a higher IL-1 beta/IL-1Ra ratio (2.49 +/- 0.56, median 2.15, range 0.35-6.12) in comparison with lower grade fibrosis (1.06 +/- 0.30, median 0.59, range 0.03-4.50) and control patients (P = 0.01). These results suggest that an imbalance between IL-1 beta and IL-1Ra, at the tissue level, may contribute to the pathogenesis and the activity of chronic active hepatitis C. (+info)
Lymphocyte subsets in renal allograft recipients with chronic hepatitis C virus infection.
BACKGROUND: The pathogenetic mechanisms of chronic hepatitis C virus (HCV) infection in renal allograft recipients are not well established. This study aimed to examine the relationship between altered immune status and HCV-related liver disease, by determining the changes in peripheral blood lymphocyte and natural killer (NK) cell subsets in these subjects. METHODS: Peripheral blood lymphocyte, NK cell and activation markers were detected by flow cytometry in renal allograft recipients with (TpC+) or without (TpC-) HCV infection, and compared with age- and sex-matched patients with post-transfusional chronic HCV infection (TfC+) and healthy controls. RESULTS: CD19+ cells were reduced in renal allograft recipients compared with controls. TpC+ subjects had increased CD3+CD8+ cells compared with controls, and increased CD3+DR+ cells but reduced CD4+ CD38+ and CD3-CD16/56+ cells compared with controls as well as TfC+ patients. TfC+ patients and controls had similar numbers and proportions for the lymphocyte subsets and NK cells. Chronic liver disease in HCV-infected renal allograft recipients was associated with increased CD3+CD16/56+ cells but reduced CD4+CD38+ cells. Reduction of CD3-CD16/56+ cells was noted in TpC+ subjects without liver disease. Yet among post-transfusional (TfC+) subjects this was associated with chronic hepatitis. CONCLUSIONS: Peripheral blood suppressor/cytotoxic T lymphocytes are increased, whereas activated helper/inducer T lymphocytes and NK cells are reduced, in renal allograft recipients with HCV infection. Increased non-MHC-restricted cytotoxic T cells and reduced NK cells are associated with the presence or absence of liver disease respectively. These data suggest that immune mechanisms are important in the pathogenesis of chronic hepatitis C after renal transplantation. (+info)