Clearance of chronic HCV infection during acute delta hepatitis. Infection. 2009;37:159-162. [PMID: 18084714 DOI: 10.1007/s15010-007-7204-7]

Functional and Clinical Characterization of Tumor-Infiltrating T Cell Subpopulations in Hepatocellular Carcinoma

Tumor-infiltrating T-lymphocytes are defined as T-lymphocytes that infiltrated into tumor tissues; however, their composition, clinical significance, and underlying mechanism in hepatocellular carcinoma (HCC) and adjacent non-tumor tissues are still not completely understood. Herein, we collected marker genes of T cell subpopulations from a previous study and estimated their relative infiltrating levels in HCC and adjacent non-tumor tissues. Specifically, the infiltrating levels of all the T cells were significantly reduced in HCC as compared with non-tumor tissues. Unsupervised clustering of the HCC samples by the T cell infiltrating levels revealed that the HCC samples could be clearly classified into two groups. The driver genes, including PTK2B, ATM, PIK3C2B, and KIT, and several CNAs were observed to be associated with reduced T cell infiltrating levels. Particularly, deletion of TP53 more frequently occurred in low T cell infiltration HCC samples and resulted in its downregulation and cell cycle progression, indicating that cell cycle progression was closely associated with reduced T cell infiltration. In contrast, for the samples with high infiltration T cells, its immune evasion might be regulated by the immune checkpoint regulators, such as PD-1/PD-L1 and CTLA4. Moreover, Olaparib, one of the PARP inhibitors, and immune checkpoint inhibitors might be therapeutic candidates for the samples from the two T cell infiltrating clusters. Clinically, the tumor-infiltrating levels of cytotoxic CD4 cell, Mucosal associated invariant T (MAIT) cell, and exhausted CD8⁺ T cell might be used as predictors for vascular invasion, recurrence, and overall survival. Collectively, we systematically evaluated the clinical significance and potential molecular mechanisms of tumor-infiltrating T cell subpopulations in hepatocellular carcinoma, which might broaden our insights into the immunological features of HCC and provide potential immunotherapeutic targets.

Hepatitis C virus seropositivity and the risk factors for transmission among blood donors in some selected centers in Lagos State, Southwest Nigeria

Introduction: Hepatitis C virus (HCV) infects about 0.5% to 2.3% of the world population with most of the cases occurring in developing countries. It is primarily transmitted through transfusion of blood and blood products. There exists dearth of information on burden and circulation of HCV and their attendant health challenges in Nigeria. This study was therefore designed to determine the seroprevalence rate and risk of HCV transmission among blood donors in Lagos State Nigeria. Methodology: Blood samples were collected between January 2002 and December 2006 from 3,002 consenting (Male = 2,922; Female = 80; Age range = 18-63; Median age = 32 years) donors in five selected public hospitals' blood donation centers between 2002 and 2006. Sera was tested for anti-HCV by ELISA technique. Demographic and other relevant information were obtained by a semi-structured questionnaire to assess risk factors for HCV transmission. Results: This study found an overall rate of 3.1% for anti-HCV among the blood donors sampled. Highest rate of 6.0% for HCV was found among participants age ranged ≥50 years and lowest in the age group 40-49 years. Prevalence of HCV was higher in female (6.3%) than in male (3.0%) and was 0.21 times less risky in female compared to their male counterparts (OR = 1.29, 95%CI 0.11-1.31). By location, MSCH had the highest HCV rate (3.9%) and lowest (2.1%) in GHOA. Sharing of sharps for tattoo/tribal markings had a statistical association (p = .0379) with HCV infection. However, no significant difference was found by gender (CI = 0.99-2.01; p = .1002), age (CI = 0.79-1.55; p = .1001) and location (p = .5326). Conclusion: The relatively high prevalence of HCV infection detected and the risk of transmission among blood donors in this study are of public health importance. Hence, the institution of appropriate measures to stem down the trend of HCV circulation among this population in Nigeria is therefore advocated.

Delayed spontaneous hepatitis C virus elimination in a renal transplant patient following graft rejection

While elimination of the hepatitis C virus (HCV) following acute infection is not uncommon, spontaneous clearance once the infection becomes chronic is extremely rare. The mechanisms involved in the clearance of chronic HCV infection without intervening antiviral therapy are not well known. Herein we describe a case of a renal transplant recipient who acquired HCV infection while immunosuppressed, experienced a rapid histological progression, and thereafter cleared the virus spontaneously long after withdrawal of immunosuppression following kidney graft rejection and failure. We review the literature and summarize the reports of spontaneous clearance of chronic HCV infection in various settings.

Unsolved Puzzles Surrounding HCV Immunity: Heterologous Immunity Adds Another Dimension

Chronic infection with hepatitis C virus (HCV) afflicts 3% of the world’s population and can lead to serious and late-stage liver diseases. Developing a vaccine for HCV is challenging because the correlates of protection are uncertain and traditional vaccine approaches do not work. Studies of natural immunity to HCV in humans have resulted in many enigmas. Human beings are not immunologically naïve because they are continually exposed to various environmental microbes and antigens, creating large populations of memory T cells. Heterologous immunity occurs when this pool of memory T cells cross-react against a new pathogen in an individual. Such heterologous immunity could influence the outcome when an individual is infected by a pathogen. We have recently made an unexpected finding that adenoviruses, a common environmental pathogen and an experimental vaccine vector, can induce robust cross-reactive immune responses against multiple antigens of HCV. Our unique finding of previously uncharacterized heterologous immunity against HCV opens new avenues to understand HCV pathogenesis and develop effective vaccines.

Hepatitis D, B and C virus (HDV/HBV/HCV) coinfection as a diagnostic problem and therapeutic challenge

Coinfection with hepatitis D virus (HDV) in chronic hepatitis B is associated with more rapid progression to liver cirrhosis. We present two cases of infection with hepatitis D, B and C viruses. Both male patients were primarily diagnosed as infected with hepatitis B virus (HBV) and hepatitis C virus (HCV), HBsAg-positive and anti-HCV-positive. The first patient was treated with interferon, lamivudine and pegylated interferon. A full virological and biochemical response was achieved. The second patient was treated with interferon and ribavirin, lamivudine and twice with pegylated interferon. In the ultrasound elastography progression of liver fibrosis to F4 was described. HDV infection should be considered in patients with HBV minireplication, high activity of aminotransferases and progression of liver disease despite a good virological response to anti-HBV treatment. Efficacy of interferon in HDV infection is severely limited.

Spontaneous clearance of hepatitis C virus during alcoholic hepatitis: the alcohol killed the virus?

Spontaneous clearance of hepatitis C virus during chronic infection is uncommon. We report the case of a patient who cleared hepatitis C virus during an episode of presumed alcoholic hepatitis. A brief discussion on the immunological aspects of chronic hepatitis C and the impact of alcohol consumption on it is presented as well.

Hepatitis B virus and hepatitis C virus dual infection

Hepatitis B virus (HBV) and hepatitis C virus (HCV) share common mode of transmission and both are able to induce a chronic infection. Dual HBV/HCV chronic coinfection is a fairly frequent occurrence, especially in high endemic areas and among individuals at high risk of parenterally transmitted infections. The intracellular interplay between HBV and HCV has not yet been sufficiently clarified, also due to the lack of a proper in vitro cellular model. Longitudinal evaluation of serum HBV DNA and HCV RNA amounts has revealed that complex virological profiles may be present in coinfected patients. Dual HBV/HCV infection has been associated to a severe course of the liver disease and to a high risk of developing hepatocellular carcinoma. Despite the clinical importance, solid evidence and clear guidelines for treatment of this special population are still lacking. This review summarizes the available data on the virological and clinical features as well as the therapeutic options of the dual HBV/HCV infection, and highlights the aspects that need to be better clarified.

Hepatic flares in chronic hepatitis C: Spontaneous exacerbation vs hepatotropic viruses superinfection

The hepatitis C virus (HCV) causes an acute infection that is frequently asymptomatic, but a spontaneous eradication of HCV infection occurs only in one-third of patients. The remaining two-thirds develop a chronic infection that, in most cases, shows an indolent course and a slow progression to the more advanced stages of the illness. Nearly a quarter of cases with chronic hepatitis C (CHC) develop liver cirrhosis with or without hepatocellular carcinoma. The indolent course of the illness may be troubled by the occurrence of a hepatic flare, i.e., a spontaneous acute exacerbation of CHC due to changes in the immune response, immunosuppression and subsequent restoration, and is characterized by an increase in serum aminotransferase values, a frequent deterioration in liver fibrosis and necroinflammation but also a high frequency of sustained viral response to pegylated interferon plus ribavirin treatment. A substantial increase in serum aminotransferase values during the clinical course of CHC may also be a consequence of a superinfection by other hepatotropic viruses, namely hepatitis B virus (HBV), HBV plus hepatitis D virus, hepatitis E virus, cytomegalovirus, particularly in geographical areas with high endemicity levels. The etiology of a hepatic flare in patients with CHC should always be defined to optimize follow-up procedures and clinical and therapeutic decisions.

Selection of conserved epitopes from hepatitis C virus for pan-populational stimulation of T-cell responses

The hepatitis C virus (HCV) is able to persist as a chronic infection, which can lead to cirrhosis and liver cancer. There is evidence that clearance of HCV is linked to strong responses by CD8 cytotoxic T lymphocytes (CTLs), suggesting that eliciting CTL responses against HCV through an epitope-based vaccine could prove an effective means of immunization. However, HCV genomic plasticity as well as the polymorphisms of HLA I molecules restricting CD8 T-cell responses challenges the selection of epitopes for a widely protective vaccine. Here, we devised an approach to overcome these limitations. From available databases, we first collected a set of 245 HCV-specific CD8 T-cell epitopes, all known to be targeted in the course of a natural infection in humans. After a sequence variability analysis, we next identified 17 highly invariant epitopes. Subsequently, we predicted the epitope HLA I binding profiles that determine their potential presentation and recognition. Finally, using the relevant HLA I-genetic frequencies, we identified various epitope subsets encompassing 6 conserved HCV-specific CTL epitopes each predicted to elicit an effective T-cell response in any individual regardless of their HLA I background. We implemented this epitope selection approach for free public use at the EPISOPT web server.

Challenges for HCV vaccine development in HIV-HCV coinfection

It is estimated that 4-5 million HIV-infected patients are coinfected with HCV. The impact of HIV on the natural course of HCV infection is deleterious. This includes a higher rate of HCV persistence and a faster rate of fibrosis progression. Coinfected patients show poor treatment outcome following standard HCV therapy. Although direct antiviral agents offer new therapeutic options, their use is hindered by potential drug interactions and toxicity in HIV-infected patients under HAART. Overtime, a large reservoir of HCV genotype 1 patients will accumulate in resource poor countries where the hepatitis C treatment is not easily affordable and HIV therapy remains the primary health issue for coinfected individuals. HCV vaccines represent a promising strategy as an adjunct or alternative to current HCV therapy. Here, the authors review the pathogenesis of hepatitis C in HIV-infected patients, with a focus on the impact of HIV on HCV-specific immune responses and discuss the challenges for vaccine development in HIV-HCV coinfection.

Spontaneous clearance of chronic hepatitis C virus infection is associated with appearance of neutralizing antibodies and reversal of T-cell exhaustion

BACKGROUND

Hepatitis C virus (HCV) readily establishes chronic infection with exhaustion of HCV-specific T cells and escape from neutralizing antibodies. Spontaneous recovery from chronic infection is rare and has never to our knowledge been studied immunologically.

METHODS

We prospectively studied, from prior to infection through >2 years of follow-up, cytokines, HCV-specific T cells, and antibodies, as well as viral sequence evolution in a white male who spontaneously cleared HCV genotype 1a after 65 weeks.

RESULTS

Significant alanine aminotransferase and plasma cytokine elevation and broad HCV-specific T-cell responses did not result in HCV clearance in the acute phase. Frequency and effector function of HCV-specific T cells decreased thereafter, and HCV titers stabilized as is typical for the chronic phase. HCV clearance after 65 weeks followed the appearance of neutralizing antibodies at week 48 and was associated with reversal of HCV-specific T-cell exhaustion, as evidenced by reduced programmed death-1 (PD-1) expression and improved T-cell function. Clearance occurred without inflammation or superinfection with hepatitis B virus, human cytomegalovirus virus, influenza, and Epstein-Barr virus.

CONCLUSIONS

T-cell exhaustion is reversible at least in the first 2 years of chronic HCV infection, and this reversion in conjunction with neutralizing antibodies may clear HCV. These findings are relevant for immunotherapy of chronic infections.

An overview of triple infection with hepatitis B, C and D viruses

Viral hepatitis is one of the major health problems worldwide, particularly in South East Asian countries including Pakistan where hepatitis C virus (HCV) and hepatitis B virus (HBV) infections are highly endemic. Hepatitis delta virus (HDV) is also not uncommon world-wide. HCV, HBV, and HDV share parallel routes of transmission due to which dual or triple viral infection can occur in a proportion of patients at the same time. HBV and HCV are important factors in the development of liver cirrhosis (LC) and hepatocellular carcinoma (HCC). In addition to LC and HCC, chronic HDV infection also plays an important role in liver damage with oncogenic potential.

The current article reviews the available literature about the epidemiology, pathogenesis, transmission, symptoms, diagnosis, replication, disease outcome, treatment and preventive measures of triple hepatitis infection by using key words; epidemiology of triple infection, risk factors, awareness status, treatment and replication cycle in PubMed, PakMediNet, Directory of Open Access Journals (DOAJ) and Google Scholar. Total data from 74 different studies published from 1983 to 2010 on triple hepatitis infections were reviewed and included in this study. The present article briefly describes triple infection with HCV, HBV and HDV.

Can chronic hepatitis C resolve spontaneously? Case report and review

Chronic hepatitis C (CHC) is variably prevalent around the world and is usually a blood-borne infection. Most patients will have subclinical infection at the onset, but patients who develop acute hepatitis can spontaneously clear the virus upon immune activation. Up to 80% of CHC patients will progress to chronic infection. CHC is unlikely to clear spontaneously. This article describes two female patients with transfusion-acquired CHC diagnosed by both positive hepatitis C virus (HCV)-Ab and hepatitis C virus-polymerase chain reaction (HCV-PCR) tests. Both patients cleared the infection spontaneously after more than 5 and 25years of CHC infection, respectively.

Hepatitis D revival

More than 30 years after Mario Rizzetto and colleagues described a new antigen in livers of HBsAg-positive patients called the "delta antigen", a re-emerging interest in hepatitis delta is currently observed. The state-of-the art on basic and clinical research on hepatitis delta was presented during a monothematic conference organized by the European Association for the Study of the Liver (EASL) in September 2010. Hepatitis delta is caused by infection with the hepatitis D virus (HDV) which requires presence of HBsAg for complete replication and transmission. Recent data confirmed the severe long-term course of HDV infection with high rates of hepatic decompensation while controversial data on the risk for the development of hepatocellular carcinoma were reported. Pegylated interferon alpha can lead to sustained HDV RNA elimination in about one quarter of patients while HBV polymerase inhibitors are ineffective against HDV. Novel treatment options include prenylation inhibitors and HBV entry inhibitors which are currently in early clinical development.

Epidemiology, pathogenesis and management of hepatitis D: update and challenges ahead

Hepatitis D is caused by infection with the hepatitis D virus (HDV) and is considered to be the most severe form of viral hepatitis in humans. Hepatitis D occurs only in individuals positive for the HBV surface antigen (HBsAg) as HDV is a defective RNA viroid that requires HBsAg for transmission. At least eight different HDV genotypes have been described and each has a characteristic geographic distribution and a distinct clinical course. HDV and HBV coinfection can be associated with complex and dynamic viral dominance patterns. Chronic HDV infection leads to more severe liver disease than HBV monoinfection and is associated with accelerated fibrosis progression, earlier hepatic decompensation and an increased risk for the development of hepatocellular carcinoma. So far, only IFN-alpha treatment has proven antiviral activity against HDV in humans and has been linked to improved long-term outcomes. Studies conducted in the past 2 years on the use of PEG-IFN-alpha show that a sustained virologic response to therapy, measured in terms of undetectable serum HDV RNA levels, can be achieved in about one quarter of patients with hepatitis D. Novel alternative treatment options including prenylation inhibitors are awaiting clinical development for use in hepatitis D.