Course Of Hepatitis C Virus Infection Research Articles

Expression of alternate reading frame protein (F1) of hepatitis C virus in Escherichia coli and detection of antibodies for F1 in Indian patients

Apart from the core (21 kD), a novel hepatitis C virus (HCV) frame shift protein (F1) is synthesized from the initiation codon of the polyprotein sequence followed by ribosomal frame shift into the −2/+1 reading frame. To date, no information is available on F1 protein of Indian isolates, and hence detection of antibodies for F1 protein in Indian patients assumes great relevance. Specific primers have been designed to amplify sequence coding for 120aa of truncated F1 (tF1). The amplified tF1 has been cloned in bacterial expression vector, pET21b for expression in Escherichia coli. Partially purified expressed protein has been subjected to western blot analysis using patients’ sera. Three HCV positive sera employed in western analysis showed positive signals to tF1, while sera from uninfected individuals failed to give any signals. Further, results of western blots, carried out with patients sera titrated with purified core protein, confirmed the presence of antibodies specific to F1. The positive signal observed for F1 in western analysis with HCV infected sera suggests that F1 protein is synthesized in the natural course of HCV infection in Indian patients as well. Presence of antibodies against F1 protein of subtype 1c has been demonstrated, for the first time, in Indian patients.

Elevated Serum Levels of Interferon‐γ–Inducible Protein–10 in Patients Coinfected with Hepatitis C Virus and HIV

Coinfection with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) is associated with an accelerated course of HCV infection and a faster progression to severe liver disease. We have investigated whether the development of liver disease in coinfected patients is associated with specific chemokine and cytokine production. Four cohorts--HCV/HIV-coinfected patients, HCV-monoinfected patients, HIV-monoinfected patients, and healthy control subjects--were studied. Serum levels of the 10-kDa interferon- gamma -inducible protein (IP-10) were higher in all 3 groups of infected patients than in control subjects (P<.0001). HCV/HIV-coinfected patients had significantly higher IP-10 levels than monoinfected patients. In HCV-monoinfected patients, liver fibrosis scores and liver enzyme levels were positively correlated with IP-10 levels. Elevated IP-10 levels are associated with and may contribute to liver damage in both HCV-monoinfected and HCV/HIV-coinfected patients.

Stable recovery from HCV in HIV–HCV co-infection under antiretroviral therapy

Co-infection by the hepatitis C virus (HCV) and the human immunodeficiency virus (HIV) is common. HIV co-infection worsens the course of HCV infection, particularly in patients with low CD4-cell count, enhancing the need to cancel HCV replication in HIV-infected patients. We report a case of spontaneous recovery of chronic HCV-infection in a HCV–HIV co-infected hemophiliac with the introduction of combined antiretroviral therapy and immune restoration. Retrospective analysis of frozen blood samples showed that a decrease in HCV-RNA in parallel with the increase of CD4 and CD8-cell counts, accompanied by a peak of transaminases. The respective effect of immune restoration and of high doses of ritonavir are discussed.

Pathogenesis of HIV-HCV coinfection

Hepatitis C virus (HCV) and HIV-1 are often harbored in the same host, establishing chronic infections typically characterized by persistent viremia. HIV-1 has deleterious effects on the course of HCV infection by increasing the rate of HCV viral persistence, quantitative HCV RNA levels, and ultimately the liver fibrosis progression rate. Conversely, HCV may blunt the effectiveness of immune reconstitution following antiretroviral therapy in HIV-infected individuals. Better understanding of the pathogenic mechanisms underlying these clinical observations may facilitate novel and effective therapeutic interventions that tackle the clinical conundrums raised by HIV/HCV coinfection.

Clinical Course of Hepatitis C Virus Infection in Renal Transplant Recipients

Patients with end-stage renal disease are at high risk for exposure to hepatitis C virus (HCV) infection. Although both viral replication and liver disease progression are accelerated after renal transplantation, the long-term impact of chronic HCV infection is unclear. Our aim was to analyze the course of HCV infection in renal transplant recipients and the effects of HCV reactivation on patient and graft survival. Methods We retrospectively examined the 21-year (1985–2006) data of 1274 renal transplant recipients, 43 of whom were anti-HCV positive at the time of transplantation. Results The mean posttransplant follow-up of 43 patients was 62.0 ± 7.3 months. At the time of transplantation, HCV RNA was positive in 11 (25.6%) patients and negative in 32 (74.4%) patients. HCV reactivation was seen in 19 (45.2%) patients at a mean time of 20.8 ± 5.7 months. In 31 (72%) patients, acute rejection occured, whereas graft loss occured in 10 (23%) patients. Three (7%) patients died. Among 43 patients, 22 (51.2%) were treated with interferon before transplantation. There was a statistically significant association between pretransplant interferon therapy and pretransplant HCVRNA level ( P = .024), but no significant association of HCV reactivation and graft rejection, mortality, or kidney survival. Conclusion HCV reactivation occurred in nearly half of the renal transplant recipients, mostly in the second year. Patient survival and graft survival were not affected by HCV reactivation. Anti-HCV positivity should not preclude chronic renal failure patients from renal transplantation.

Influence of inhibitory killer immunoglobulin‐like receptors and their HLA‐C ligands on resolving hepatitis C virus infection

An estimated 2%-3% of the world's population is chronically infected with hepatitis C virus (HCV) and this is a major cause of liver disease worldwide. Following acute infection, outcome is variable with acute HCV successfully resolved in some individuals (20%-30%), but in the majority of cases the virus is able to persist. Co-infection with human immunodeficiency virus has been associated with a negative impact on the course of HCV infection. The host's immune response is an important correlate of HCV infection outcome and disease progression. Natural killer (NK) cells provide a major component of the antiviral immune response by recognising and killing virally infected cells. NK cells modulate their activity through a combination of inhibitory and activatory receptors such as the killer immunoglobulin-like receptors (KIRs) that bind to human leukocyte antigen (HLA) Class I molecules. In this workshop component, we addressed the influence of KIR genotypes and their HLA ligands on resolving HCV infection and we discuss the implications of the results of the study of Lopez-Vazquez et al. on KIR and HCV disease progression.

Production of Infectious Hepatitis C Virus of Various Genotypes in Cell Cultures

A unique hepatitis C virus (HCV) strain JFH-1 has been shown to replicate efficiently in cell culture with production of infectious HCV. We previously developed a DNA expression system containing HCV cDNA flanked by two self-cleaving ribozymes to generate HCV particles in cell culture. In this study, we produced HCV particles of various genotypes, including 1a (H77), 1b (CG1b), and 2a (J6 and JFH-1), in the HCV-ribozyme system. The constructs also contain the secreted alkaline phosphatase gene to control for transfection efficiency and the effects of culture conditions. After transfection into the Huh7-derived cell line Huh7.5.1, continuous HCV replication and secretion were confirmed by the detection of HCV RNA and core antigen in the culture medium. HCV replication levels of strains H77, CG1b, and J6 were comparable, whereas the JFH-1 strain replicates at a substantially higher level than the other strains. To evaluate the infectivity in vitro, the culture medium of JFH-1-transfected cells was inoculated into naive Huh7.5.1 cells. HCV proteins were detected by immunofluorescence 3 days after inoculation. To evaluate the infectivity in vivo, the culture medium from HCV genotype 1b-transfected cells was inoculated into a chimpanzee and caused a typical course of HCV infection. The HCV 1b propagated in vitro and in vivo had sequences identical to those of the HCV genomic cDNA used for cell culture transfection. The development of culture systems for production of various HCV genotypes provides a valuable tool not only to study the replication and pathogenesis of HCV but also to screen for antivirals.

Impact of the genetic restriction of virus-specific T-cell responses in hepatitis C virus infection

The immunobiology of hepatitis C virus (HCV) is significantly influenced by the host immune response to the virus, especially by virus-specific T-cell responses. Virus-specific T cells are restricted by human leucocyte antigen class I and II molecules. Of note, associations between these polymorphic loci and outcome and course of HCV infection have been reported in large and well-documented cohorts. This review will briefly summarize these studies and focus especially on the immunological and virological basis for the reported associations. The outcome and course of HCV infection is most likely determined by a complex interplay of genetic, immunological and virological factors. A better understanding of these host-virus interactions is essential not only to gain better insights into the mechanisms of viral clearance and persistence but also for the development of new antiviral vaccine strategies.

Neutralizing antibodies in hepatitis C virus infection

Hepatitis C virus (HCV) is a major cause of hepatitis world-wide. The majority of infected individuals develop chronic hepatitis which can then progress to liver cirrhosis and hepatocellular carcinoma. Spontaneous viral clearance occurs in about 20%-30% of acutely infected individuals and results in resolution of infection without sequaelae. Both viral and host factors appear to play an important role for resolution of acute infection. A large body of evidence suggests that a strong, multispecific and long-lasting cellular immune response appears to be important for control of viral infection in acute hepatitis C. Due too the lack of convenient neutralization assays, the impact of neutralizing responses for control of viral infection had been less defined. In recent years, the development of robust tissue culture model systems for HCV entry and infection has finally allowed study of antibody-mediated neutralization and to gain further insights into viral targets of host neutralizing responses. In addition, detailed analysis of antibody-mediated neutralization in individual patients as well as cohorts with well defined viral isolates has enabled the study of neutralizing responses in the course of HCV infection and characterization of the impact of neutralizing antibodies for control of viral infection. This review will summarize recent progress in the understanding of the molecular mechanisms of antibody-mediated neutralization and its impact for HCV pathogenesis.

Does Cyclosporine Have a Beneficial Effect on the Course of Chronic Hepatitis C Infection After Renal Transplantation?

The aim of our study was to assess the long-term liver histology in renal transplant patients infected with hepatitis C virus (HCV) who were treated with a cyclosporine-based regimen. Among 55 anti-HCV(+)/RNA(+) patients, liver biopsies (LB) were requested every 3 to 4 years after transplantation: two LBs ( n = 55); three LBs ( n = 44); four LBs ( n = 10). Overall, the rate of liver fibrosis progression was 0.07 ± 0.03 Metavir U/y. Only three patients out of 55 (5.4%) developed cirrhosis. Liver fibrosis remained stable throughout follow-up in 21 patients; increased in 21 patients; and improved in the remaining 13 patients. The incidence of posttransplant diabetes mellitus was low (9%). We concluded that HCV infection is not harmful to liver histology in more than 50% of renal transplant patients with grafts functioning more than 6 years. Cyclosporine might have beneficial effects on the natural course of HCV infection after renal transplantation.

Analysis of interleukin (IL)-1β IL-1 receptor antagonist, soluble IL-1 receptor type II and IL-1 accessory protein in HCV-associated lymphoproliferative disorders

Hepatitis C virus (HCV) causes hepatitis, liver cirrhosis and hepatocellular carcinoma, and may also induce type II mixed cryoglobulinemia syndrome (MC), a disease characterized by clonal B-cell lymphoproliferations that can evolve into non-Hodgkin's lymphoma (NHL). Interleukin-1 (IL-1) is a cytokine that plays an important role in initiating the cascade of events of immunoinflammatory responses through costimulation of T lymphocytes, B-cell proliferation, induction of adhesion molecules and stimulation of the production of other inflammatory cytokines. The role of IL-1 in immunoinflammatory responses is highlighted by the presence of endogenous regulators (IL-1 receptor antagonist, soluble receptors type 1 and II, human IL-1 accessory protein) that, when secreted into the blood stream may serve as endogenous regulators of IL-1 action. The aim of this study was to evaluate whether abnormalities in the blood levels of IL-1beta IL-1 receptor antagonist, soluble IL-1 receptor type II and human IL-1 accessory protein in HCV+ patients are associated with development of MC and/or NHL. Relative to healthy controls, we observed: i) an increase in the circulating levels of IL-1beta in HCV+ patients simultaneously affected by NHL; ii) increased levels of IL-1 accessory protein in patients singly infected by HCV; iii) increase of IL-1 receptor antagonist in HCV+ patients and in those affected also by NHL with or without MC; iv) a homogeneous increase of sIL-1R type II in all the subgroup of patients. These data indicate that an attempt to increased circulating levels of IL-1 inhibitors occurs at different extent in the course of HCV infection as well as in its progression to NHL and/or MC.

Hepatitis C and steatosis: a reappraisal

The overall prevalence of steatosis in patients with Hepatitis C virus (HCV) chronic infection is 55.5% (range 34.8-81.2%). This is a two to threefold increase compared with the prevalence of steatosis in chronic hepatitides because of other aetiologies and of the figures expected on the grounds of a steatosis-HCV chance association. HCV genotype 3 (HCV-3) has specific epidemiological features; furthermore, as compared with HCV-non-3 genotypes, it is associated with a higher prevalence (74.1%vs 47.9%, P < 0.01) and with more severe grades of steatosis (prevalence of grade 3 steatosis 29.6 vs 5.5 P < 0.01). Host and viral factors play a role, although to a variable extent, in the pathogenesis of HCV-3 and non-3 steatosis. HCV load and body mass index are associated with steatosis in HCV-3 and in HCV-non-3 patients respectively. Serum cholesterol levels and liver steatosis at baseline follow an inverse relationship in HCV infection. As hypocholesterolaemia corrects only in those sustained responders to antiviral treatment both in genotype 3 and in non-3 genotypes, the occurrence of a virally induced, acquired and reversible hypobetalipoproteinaemia seems plausible. Steatosis affects the natural course of HCV infection: it is associated with fibrosis, a possible mediator of increased risk to develop type 2 diabetes, it impairs the response to antiviral treatment in HCV-3 patients and might constitute a risk factor for the development of hepatocellular carcinoma. These observations indicate the need to evaluate the efficacy of combined antiviral and 'metabolic' approaches vs standard antiviral regimes in patients with steatosis and HCV chronic infection.

Natural history and predictors of severity of chronic hepatitis C virus (HCV) and human immunodeficiency virus (HIV) co-infection

Co-infection by the hepatitis C virus (HCV) is observed in up to 30% of HIV-infected individuals. In studies conducted in the 'pre-HAART era', the late consequences of HCV-related chronic liver disease were overshadowed by extra-hepatic causes of deaths, related to severe immune deficiency, and the impact of HCV infection on mortality of HIV-infected patients was low. While the development of HAART has resulted in a significant decrease in morbidity and mortality amongst HIV-infected patients, this clear benefit allowed the expression of liver-related complications associated with HCV chronic infection. The impact of HCV on HIV remains debated but HIV infection significantly modifies the natural history of HCV infection. HIV infection increases levels of HCV viraemia by 2- to 8-fold, resulting in a significant decrease in spontaneous recovery of acute hepatitis. HIV co-infection also worsens the histological course of HCV infection by increasing and accelerating the risk of cirrhosis or leading to rare but lethal fibrosing cholestatic hepatitis. Liver disease is now one of the leading causes of morbidity and mortality in co-infected patients, even if HAART and especially protease inhibitors, may decrease the severity of the liver disease and the liver-related mortality. Several non-exclusive pathogenic processes explain the increasing rate of liver complications associated with HCV-related liver disease.

Single nucleotide polymorphisms and haplotypes in the IL10 region associated with HCV clearance

Hepatitis C virus (HCV) is an infectious blood-borne pathogen that usually persists as a chronic infection. However, approximately 15% of the time, patients can clear the virus, indicating that host differences could be critical in determining the course of HCV infection. The inflammatory response is crucial to resolving or failing to resolve an acute HCV infection. Some previous reports have implicated interleukin 10 (IL10) polymorphisms with successful anti-HCV therapy and natural viral clearance. We tested 54 single nucleotide polymorphisms (SNPs) in the IL10 region (+/-300 kb and 24 within the IL10 gene itself), which contains 13 genes including the IL10 immunomodulatory paralogs IL19, IL20, and IL24, for association with HCV clearance vs persistence. SNPs from two haplotype block regions, one at IL10 and the other from IL19/IL20, were associated with HCV clearance in African Americans (91 clearance cases and 183 chronically infected matched controls; P=0.05-0.002) while with expectation-maximization algorithm-reconstructed haplotypes, these associations remained (P=0.05-0.002). However, no significant associations were detected in European Americans (108 clearance and 245 chronic). Our results indicate that variants of the immunomodulatory IL10 and IL19/IL20 genes may be involved in natural clearance of HCV in the African-American population.

Heterologous T cell immunity in severe hepatitis C virus infection

Hepatitis C virus (HCV) can cause liver disease of variable severity. Expansion of preexisting memory CD8 T cells by cross-reactivity with a new heterologous virus infection has been shown in mice to shape the repertoire of the primary response and to influence virus-related immunopathology (Selin, L.K. 2004. Immunity. 20:5–16). To determine whether this mechanism can influence the course of HCV infection, we analyzed the features of the HCV-specific CD8 T cell response in eight patients with acute HCV infection, two of whom had a particularly severe illness. Patients with severe hepatitis, but not those with mild disease, showed an extremely vigorous CD8 T cell response narrowly focused on a single epitope (NS3 1073–1081), which cross-reacted with an influenza neuraminidase sequence. Our results suggest that CD8 T cell cross-reactivity influences the severity of the HCV-associated liver pathology and depicts a model of disease induction that may apply to different viral infections.

Mitogen-induced upregulation of hepatitis C virus expression in human lymphoid cells

Considering growing evidence indicating that hepatitis C virus (HCV) replicates in lymphoid cells, establishment of a reliable and sensitive method for detection of HCV in these cells may provide means for monitoring the infection and the efficacy of sterilizing antiviral therapy. In this study, conditions for ex vivo augmentation and detection of the HCV genome in peripheral blood mononuclear cells (PBMCs) from patients with chronic hepatitis C (CHC) or after a sustained virological response (SVR) to antiviral treatment were assessed. Following stimulation with combinations of mitogens and/or cytokines, PBMCs and, in certain cases, affinity-purified T and B cells were examined for HCV positive- and negative-strand RNA by using RT-PCR followed by nucleic acid hybridization, while the presence of viral NS3 protein was determined by flow cytometry. HCV RNA augmentation was assessed by quantification of Southern and dot-blot hybridization signals. The results showed that treatment of peripheral lymphoid cells with mitogens stimulating T- and B-cell proliferation and with cytokines supporting their growth significantly increased HCV RNA detection in patients with both CHC and SVR. This enhancement was up to 100-fold for the HCV genome and fivefold for the NS3 protein compared with untreated cells. In conclusion, HCV RNA can be readily detected in circulating lymphoid cells in progressing hepatitis C and following SVR after ex vivo cell stimulation. As such, this method offers a new investigative tool to study HCV lymphotropism and to monitor virus presence during the course of HCV infection.

Nonstructural 5A gene variability of hepatitis C virus (HCV) during a 10-year follow up

Seven patients with chronic hepatitis C virus (HCV) infection were followed up for 10 years in order to analyze the molecular evolution of the HCV nonstructural 5A (NS5A) gene. Serum samples were obtained from seven patients with anti-HCV who were HCV-RNA positive. The HCV NS5A region, including the interferon sensitivity-determining region (ISDR), protein kinase R binding domain (PKR-BD), and V3 was amplified and cloned, and then sequenced. The nucleotide sequences of the region at the beginning and at the end of the 10 years were aligned with the CLUSTAL W program, version 1.8, and the corresponding amino-acid sequences were deduced. The three serine residues at positions 2197, 2201, and 2204, suggested to be important for hyperphosphorylation of NS5A, were highly conserved in different patients and were within the quasispecies of each patient. The wild-type ISDR or minimally mutated strain was dominant in all the patients and the number of quasispecies decreased over time. Our findings showed that the functional domains of NS5A were generally conserved over an interval of 10 years. Quasispecies distribution was variable and distinctly clustered over time during the natural course of HCV infection. These results may contribute to better understanding of HCV natural infection.

Co-infections with Hepatitis G and TT Virus in Patients with Chronic Hepatitis C in Hungary

The significance of co-infections with novel hepatitis viruses Hepatitis G (GBV-C, HGV) and TT virus (TTV) in chronic hepatitis C is not clear. We determined the prevalence of HGV RNA and TTV DNA in chronic hepatitis C patients and in asymptomatic hepatitis C virus (HCV) carriers, and assessed the influence of these agents on the course of HCV infection. Seventy-seven patients with chronic hepatitis C--50 of them treated with interferon (IFN)--and 33 HCV carriers with normal alanine aminotransferase have been investigated. Previous HBV infection was detected by testing serum HBsAg and aHBc. HGV RNA and TTV DNA were detected by PCR. In the healthy population, the prevalence of anti-HCV was 0.3%, HGV RNA 8.0% and TTV DNA 18.5%. In chronic hepatitis C HGV RNA occurred in 9.09% and TTV DNA in 40.25% of cases. In IFN-treated patients with sustained remission, the frequency of TTV was 20% vs. 45.7% found in non-responders. Among asymptomatic HCV-carriers, the prevalence of HGV RNA was 9.09% and TTV DNA 75.7%. Neither HGV RNA nor TTV DNA had apparent effect on the HCV infection. TTV was detected with the lowest frequency in persons with sustained remission due to IFN, suggesting antiviral effect of IFN on TTV.

Hepatitis C infection in children with haemophilia: a pilot study

Many haemophilia patients were infected with hepatitis C virus (HCV) in childhood after transfusion with inadequately or non-virus inactivated clotting factor products. Limited information is available on the clinical course of HCV infection in children. To assess the clinical consequences of hepatitis C in these young patients we performed a pilot study of 31 patients with haemophilia, infected with HCV before the age of 13. Current median age was 20 years. Nineteen (61%) patients had chronic hepatitis C, whereas the remaining 12 patients spontaneously cleared HCV. The median duration of infection was 17 years. Among patients chronically infected with HCV, an enlarged liver and/or spleen on ultrasound was present in 59%, whereas 63% had abnormal aminotransferases and/or gamma-GT values. In conclusion, 39% of the patients infected in childhood cleared HCV spontaneously. The majority of the patients with chronic hepatitis C had ultrasound and/or laboratory abnormalities and these findings may be associated with the presence of chronic liver disease.

No adverse effect of ABVD chemotherapy in a patient with chronic hepatitis C and Hodgkin’s disease

There is insufficient information on the effects of chemotherapy protocols for Hodgkin's disease (HD) and the course of coexisting hepatitis C virus (HCV) infection. A single literature case reported a patient with HD who developed fulminant hepatitis and hepatic coma after receiving chemotherapy. The case described here is of a female patient previously exposed to prolonged war stress, complicated by intravenous drug abuse and chronic hepatitis C. One year after diagnosis of HCV infection she was diagnosed with HD (nodular sclerosis type II, clinical stage IIIB). The patient received six cycles of ABVD chemotherapy (doxorubicin, bleomycin, vinblastine and dacarbazine) resulting in complete remission of HD. There was no hepatitis flare either during or after chemotherapy. In conclusion, there were no adverse effects of the ABVD regimen on the course of HCV infection in this patient who was successfully treated for HD. Because concurrent HCV infection and HD is extremely rare, we discuss here the possibility of the synergistic contribution of chronic war stress and hepatitis C infection in the pathogenesis of HD.