Virological and epitope evolution of HCV infection from acute hepatitis C to subsequent episodes of HCV-related acute liver cell necrosis

Immune Evasion Strategies during Chronic Hepatitis B and C Virus Infection

Both hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are a major global healthcare problem with more than 240 million and 70 million infected, respectively. Both viruses persist within the liver and result in progressive liver disease, resulting in liver fibrosis, cirrhosis and hepatocellular carcinoma. Strikingly, this pathogenesis is largely driven by immune responses, unable to clear an established infection, rather than by the viral pathogens themselves. Even though disease progression is very similar in both infections, HBV and HCV have evolved distinct mechanisms, by which they ensure persistence within the host. Whereas HCV utilizes a cloak-and-dagger approach, disguising itself as a lipid-like particle and immediately crippling essential pattern-recognition pathways, HBV has long been considered a "stealth" virus, due to the complete absence of innate immune responses during infection. Recent developments and access to improved model systems, however, revealed that even though it is among the smallest human-tropic viruses, HBV may, in addition to evading host responses, employ subtle immune evasion mechanisms directed at ensuring viral persistence in the absence of host responses. In this review, we compare the different strategies of both viruses to ensure viral persistence by actively interfering with viral recognition and innate immune responses.

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.

Clinical presentation, outcome, and response to therapy among patients with acute exacerbation of chronic hepatitis C

BACKGROUND & AIMS

The slow asymptomatic progression of chronic hepatitis C (CHC) can be interrupted by an acute exacerbation, characterized by increased serum levels of alanine aminotransferase (ALT) and bilirubin and other symptoms of acute hepatitis. We aimed to provide more information about the clinical presentation of acute exacerbation of CHC.

METHODS

We identified 82 consecutive patients, from 2 locations in Italy, who had an acute exacerbation of CHC from January 2005 through June 2010; we followed them up for a median period of 36 months. These cases were hepatitis C virus (HCV) RNA positive, hepatitis B surface antigen-negative, and had not received anti-HCV therapy. They were matched with 82 subjects with hepatitis C without reactivation for age, sex, and HCV genotype (controls). Sixty-nine cases and 73 controls were followed up for at least 2 years. Liver biopsy specimens had been taken from 23 cases and 31 controls-once before enrollment in the study and once during the follow-up period.

RESULTS

HCV genotype 2 was detected in 46.4% of cases, and HCV genotype 1 was detected in 43.9%. Among cases, the mean ALT level was 1063 ± 1038 IU/dL, and the mean total bilirubin level was 15.87 ± 7.15 mg/dL. A higher percentage of cases carried the interleukin-28B CC genotype than controls (40.2% vs 24.4%; P < .05). Among cases, 43.5% had a steady increase in ALT level (>2-fold baseline value); for 56.5% of these patients, ALT levels returned to baseline values before the acute exacerbation of chronic hepatitis. Based on comparisons of biopsy specimens, 18 cases (78.3%) and 11 controls (35.5%) had increasing fibrosis, with Ishak scores increasing by more than 2 (P < .005); 14 cases (60.9%) and 3 controls (9.6%) had increases in necroinflammation of more than 2 points (P < .005). Thirty-two cases (46.4%) and 38 controls (52%) received treatment with pegylated interferon and ribavirin; a sustained virologic response was achieved in 26 cases (81.2%) and 23 controls (60.5%).

CONCLUSIONS

Although an acute exacerbation of chronic hepatitis is a serious medical condition, most patients achieve a sustained virologic response after treatment with pegylated interferon and ribavirin.

Phylogeny and phylodinamic of Hepatitis C in Italy

Hepatitis C virus infection (HCV) is one of the most pressing health emergencies in the world with a global prevalence of about 170 million people chronically infected worldwide. In Europe, Italy has the highest HCV prevalence (3 - 4.4%) with peaks of 12.6 - 26% in Southern regions and the major islands. In Italy HCV genotype 1b prevails, and genotype 4 is mainly found in the south of the country where the prevalence is particularly high in regions such as Calabria.

Phylogenetics analysis is a molecular tool widely used to study rapidly-evolving RNA viruses that establish chronic infections such as HCV. Searching the scientific literature, it was found that thirty-nine genetic studies on HCV genotypes have been carried out in Italy between 1997 to 2012 years. However, phylogenetic analysis was performed only in fourteen out of thirty-nine HCV studies (36%) considered. Monitoring the genetic evolution of HCV is an essential step to control the local as well as global HCV epidemic and to develop efficient preventive and therapeutic strategies.

Improvement in the aetiological diagnosis of acute hepatitis C: a diagnostic protocol based on the anti-HCV-IgM titre and IgG Avidity Index

BACKGROUND

The gold standard for the diagnosis of acute hepatitis C (AHC) is seroconversion to anti-HCV/HCV-RNA positivity, an occurrence frequently missed in clinical practice.

OBJECTIVES

This study aims to diagnose AHC by the combined use of the HCV Avidity Index (HCV-AI) and HCV-IgM titre.

STUDY DESIGN

We enrolled 45 patients with AHC diagnosed by seroconversion to anti-HCV/HCV-RNA positivity and 36 with exacerbation of chronic hepatitis C (e-CHC) diagnosed at least 1 year earlier. HCV-IgM titres were determined by a commercial enzyme-linked immunosorbent assay (ELISA) and HCV-AI by an ELISA for detection of HCV IgG with a partial modification. For each test, specific cut-off values at four selected checking points were established during the observation (<10 days, 11-15 days, 16-20 days and >20 days from the onset of symptoms): for the HCV-IgM assay, the highest value in e-CHC +5% and for HCV-AI assay, the lowest value in e-CHC -5%.

RESULTS

Around 90% of patients with AHC or e-CHC were correctly diagnosed at all checking points by combining the results of both tests. This practice afforded an improvement in sensitivity for the diagnosis of AHC, with the highest values at first and third checking points (92.3% and 92.6%, respectively) and an improvement in negative predictive value (NPV), with the highest value at first checking point (92.6%).

CONCLUSIONS

The diagnosis of AHC, made by seroconversion to anti-HCV/HCV-RNA positivity, was confirmed in more than 90% of patients by combining the results of IgG Avidity Index (IgG-AI) and HCV-IgM obtained in a single serum sample.