Characterization of the cellular immune response in hepatitis C virus infection

Hepatitis C Virus Clearance by Direct-acting Antiviral Results in Rapid Resolution of Hepatocytic Injury as Indicated by Both Alanine Aminotransferase and Aspartate Aminotransferase Normalization

Background and Aims: Hepatitis C virus (HCV) infection results in hepatocytic injury with elevation of both alanine aminotransferase (ALT) and aspartate aminotransferase (AST). It remains to be determined if direct-acting antiviral treatment can terminate hepatocytic injury following virologic response. To this end, we evaluated the pattern and predicting factors of ALT and AST normalization during and after direct-acting antiviral treatment with sustained virologic response at 12 weeks (SVR12). Methods: Single-center retrospective study on 115 HCV-infected patients who achieved SVR12 was performed. Results: At treatment week 2, 100% and 45.9% showed decline in HCV RNA to <700 IU/mL and undetectable levels, respectively, and this was associated with 85.5%, 83.9% and 77.4% ALT normalization, AST normalization and ALT and AST normalization. At end of treatment, 85.6% of patients with baseline elevation of both ALT and AST had normalization of both ALT and AST. At posttreatment weeks 12 and 24, 90.8% and 94.8% had normalization of both ALT and AST. HCV clearance also resulted in further decline of both ALT and AST in those with baseline <40 IU. Univariate analysis showed baseline Child-Pugh score of <6, model for end-stage liver disease score of <10, HCV genotype 1, and HCV RNA of <500 IU/mL at treatment week 2 were associated with sustained normalization of both ALT and AST at posttreatment week 12. On multivariate analysis, baseline model for end-stage liver disease score of <10 was significantly associated with normalization of both ALT and AST at posttreatment week 12, independent of baseline Child-Pugh score <6, HCV genotype 1, and HCV RNA of <500 IU/mL at treatment week 2. Conclusions: During direct-acting antiviral therapy, 85.5% and 83.9% had normalization of both ALT and AST as early as in week 2, providing biochemical evidence of hepatocytic injury resolution. Sustained normalization of both ALT and AST was seen in 90.8% at posttreatment weeks 12, and was independently associated with baseline model for end-stage liver disease score of <10.

Hepatitis C virus core impacts expression of miR122 and miR204 involved in carcinogenic progression via regulation of TGFBRAP1 and HOTTIP expression

Background

Despite the breadth of understanding the noncoding RNAs' function in molecular biology, their functional roles in hepatocellular carcinoma (HCC) is poorly understood. In this study, we investigated the effect of hepatitis C virus (HCV) core upon the expression of noncoding RNAs.

Methods

The lncRNAs, mRNAs, and circRNAs were employed for identification of HCV core protein gene expression in human Huh7 hepatoma (Huh7) cell line. In data analysis, we applied a threshold that eliminated all genes that were not increased or decreased by at least a 2-fold change in a comparison between transfected and control cells. Hierarchical Clustering and the Kyoto encyclopedia of genes and genome pathway analyses were performed to show the distinguishable lncRNA, mRNAs, and circRNAs expression pattern among samples.

Results

The array data showed that 4,851 lncRNAs, 4,785 mRNAs, and 823 circRNAs were 2-fold up-regulated but 3,569 lncRNAs, 3,192 mRNAs, and 419 circRNAs were 2-fold down-regulated in Huh 7-core cells. The genes in the enriched set were associated with macromolecule and nucleic acid metabolic processes, DNA damage response and regulation of voltage-gated calcium channel. We identified 10 genes from the selected 14 genes that were higher or lower expression in Huh7-core cells than that of Huh7-vector cells by quantitative real-time polymerase chain reaction. Interestingly, overexpression of miR122 and miR204 partly abrogated the expression of TGFBRAP1 and HOTTIP, and increased the HPCAL1 expression in the predicted carcinogenic pathways.

Conclusion

Our data suggests that the pathways of miR204-HPCAL1-lncRNAHOTTIP and miR122-TGFBRAP1 were likely involved in the carcinogenic progress due to the presence of HCV core, and that overexpression of miR122 and miR204 might inhibit the HCC progress by down-regulation of TGFBRAP1 and HOTTIP expression.

Virus-Specific Cellular Response in Hepatitis C Virus Infection

Studies performed on chimpanzees and humans have revealed that strong, multispecific and sustained CD4(+) and CD8(+) T cell immune responses is a major determinant of hepatitis C virus (HCV) clearance. However, spontaneous elimination of the virus occurs in minority of infected individuals and cellular response directed against HCV antigens is not persistent in individuals with chronic infection. This review presents characteristics of the HCV-specific T cell response in patients with different clinical course of infection, including acute and chronic infection, persons who spontaneously eliminated HCV and non-infected subjects exposed to HCV. Detection of HCV-specific response, especially in non-infected subjects exposed to HCV, may be indicative of HCV prevalence in population and rate of spontaneous viral clearance. Understanding the mechanisms and role of HCV-specific cellular immune response would contribute to better understanding of HCV epidemiology, immunopathogenesis and may help to design an effective vaccine.

Hepatitis C virus-specific cellular immune responses in sustained virological responders with viral persistence in peripheral blood mononuclear cells

BACKGROUND & AIMS

Hepatitis C virus (HCV)-RNA detection in peripheral blood mononuclear cells (PBMCs) after recovery from HCV infection, is a type of occult HCV infection although is unclear how the viral persistence in PBMCs affects HCV-specific T-cell responses. The aim of this study was to investigate if cellular immune responses are modified by HCV persistence in PBMCs.

METHODS

HCV-specific CD4(+) and CD8(+) T-cell responses against six HCV peptides, situated within the non-structural (NS) proteins NS3, NS4b and NS5b, were measured by flow cytometry-through intracellular detection of gamma interferon (IFN-γ) or interleukin 4 (IL-4) and CD69 expression- in 27 sustained virological responders (SVR): 13 with and 14 without occult HCV infection in PBMCs, detected by strand-specific real-time PCR. Ten healthy individuals and 14 chronically infected patients with viraemia, were included as controls.

RESULTS

SVR without occult infection showed a higher percentage of activated CD4(+) cells against peptides belonging to NS3 (p124, p153) and NS5b (p257, p294), activated CD8(+) cells against NS3 (p124, p153, p158) and NS5b-p294, as well as an elevated percentage of CD4(+) cells releasing IFN-γ + IL-4 against NS3-p153, and by CD8(+) cells against NS3 (p124, p153). SVR without occult infection showed a higher percentage of activation and release of IFN-γ + IL-4 by both cell subpopulations than the two group of controls, in contrast to SVR with occult infection.

CONCLUSION

The lower HCV-specific T-cell response found in SVR with occult infection indicates that the immune response may be impaired when the virus persists in PBMCs.

Seronegative hepatitis C virus infection

Hepatitis C virus (HCV) is a major cause of liver disease worldwide. The routine diagnostics identifying HCV infection include testing for specific anti-HCV antibodies by enzyme-linked immnunosorbent assay and viral genetic material in serum or plasma. However, a small proportion of patients persistently infected with HCV, in whom anti-HCV are undetectable, constitute a serious diagnostic and possibly epidemiologic problem, as they could facilitate pathogen spread in the population. This type of infection is termed seronegative or serosilent. Seronegative HCV infection is currently of great interest to both scientists and physicians. The review presents epidemiological data concerning the prevalence of seronegative HCV infection in HIV/HCV co-infected individuals, hemodialysis patients, and blood and organ donors. The possible mechanisms behind this atypical course of infection are discussed. Furthermore, the differences between seronegative and occult infections and prolonged seroconversion are explained.

Ever closer to a prophylactic vaccine for HCV

Introduction

With 3 – 4 million new infections occurring annually, hepatitis C virus (HCV) is a major global health problem. There is increasing evidence to suggest that HCV will be highly amenable to a vaccine approach, and despite advances in treatment, a vaccine remains the most cost-effective and realistic means to significantly reduce the worldwide mortality and morbidity associated with persistent HCV infection.

Areas covered

In this review we discuss immune responses to HCV during natural infection, and describe how they may inform vaccine design. We introduce the current candidate vaccines for HCV and compare how these fare against the expected requirements of an effective prophylactic HCV vaccine in relation to the breadth, functionality, magnitude and phenotype of the vaccine-induced immune response.

Expert opinion

Although the correlates of immune protection against HCV are not completely defined, we now have vaccine technologies capable of inducing HCV-specific adaptive immune responses to an order of magnitude that are associated with protection during natural infection. The challenge next is to i) establish well-characterised cohorts of people at risk of HCV infection for vaccine efficacy testing and ii) to better understand the correlates of protection in natural history studies. If these can be achieved, a vaccine against HCV appears a realistic goal.

Association of Hepatitis C Virus Infection with Type II Diabetes in Ethiopia: A Hospital-Based Case-Control Study

Background. Chronic hepatitis C virus (HCV) has become the global “epidemic” with an estimated 123 million people currently infected worldwide. As the same time diabetes is also rapidly emerging as a global health care problem that threatens to reach pandemic levels by 2030. Objective. To investigate the magnitude of HCV infection in type II diabetes as compared to controls. Methodology. A case control study design was conducted at Jimma University Specialized Hospital from May to June 2010. A total of 604 study subjects were included in this study. Sociodemographic and risk factor data were collected by questionnaire. From serum sample, HCVAb screening was done by rapid antibody screening test. Liver functioning tests and total cholesterol tests were done by Dr. Lange LP 800 spectrophotometer. Results. The prevalence of HCV in type II diabetes and nondiabetic controls was 9.9% and 3.3%, respectively. In multivariate analysis, HCV seropositives have high risk of developing diabetes as compared with seronegatives (AOR = 2.997, 95% CI: (1.08, 8.315)). Conclusion. In this study, we found a positive association between past HCV infection and type II diabetes. As we did not perform HCV RNA test, we could not assess the association with HCV viremia.

Advances in hepatitis C virus vaccines, Part one: Advances in basic knowledge for hepatitis C virus vaccine design

INTRODUCTION

Around 3% of the world population is infected with HCV, with 3 - 4 million newly infected subjects added to this reservoir every year. At least 10% of these people will develop liver cirrhosis or cancer over time, while no approved vaccine against HCV infection is available to date.

AREAS COVERED

This paper includes a detailed and correlated patent (selected by HCAPLUS search database) and literature (searched by PubMed) review on the HCV genome, proteins and key epitopes (including underestimated HCV proteins, alternate reading frame proteins), HCV immunology, immunosuppressive mechanisms and protective correlations of immunity in acute and chronic states of infection (features for prophylactic and therapeutic HCV vaccine design), recent HCV cell culture systems (HCV/JFH1) and animal models. In part two of this review, advances in HCV vaccine formulations and modalities as well as a detailed list of the current trials for HCV vaccine and discussion of the pros and cones of different strategies will be provided.

EXPERT OPINION

By using the advanced basic knowledge and tools obtained about HCV vaccinology in recent years and the application of novel formulations and modalities, at least partially effective vaccines will become available in the near future to prevent (or treat) the chronic (if not the acute) state of HCV infection. A few of such vaccines are already in clinical trials.

Serial measurements of hepatitis C viral load by real-time polymerase chain reaction among recipients of living-donor renal transplants: a short-term follow-up study from a single center

There is a high prevalence of hepatitis C virus (HCV) infection among immunosuppressed patients including renal transplant recipients. The study investigated serum viral loads for up to 6 months posttransplantation among these patients. Serum viral load was serially monitored using real-time polymerase chain reaction (PCR) in 25 HCV-positive renal transplant recipients pretransplantation as well as day 10 and 6 months posttransplantation. A liver biopsy specimen obtained under vision at the time of transplantation was analyzed for viral load as well as for histological changes. There was increased viremia at day 10 followed by a significant (2 log) reduction at 6 months posttransplantation. Pretransplantation serum and intrahepatic viral load showed significant positive correlations (r = 0.727; P = .001), the latter also reflecting liver fibrosis score (r = 0.423; P = .05). The findings suggested that serum viral load reflects intrahepatic viral load, which in turn correlates with liver fibrosis. At 6 months posttransplantation, the modulatory effects of immunosuppressive drugs and of the host immune response may lead to a reduced viral load.

Targeting the inflammation in HCV-associated hepatocellular carcinoma: a role in the prevention and treatment

Epidemiological, preclinical and clinical studies demonstrated that chronic inflammation induced by hepatitis C virus (HCV) is crucial in hepatocellular carcinogenesis. The interaction between hepatocytes and microenvironment regards virus, inflammatory and immunocompetent cells, chemo- and cyto-kines, reactive oxygen species (ROS) and nitric oxide (NO), generating cell transformation. We suggest hepatocarcinoma (HCC) as a model in which the targeting of microenvironment determine neoplastic transformation. The present review focuses on: the role of inflammation in carcinogenesis, the clinical impact of HCC and the inadequacy of the actual therapy, the chemoprevention targeting the microenvironment.