HCV virology and diagnosis.

Hepatitis C virus (HCV) infection is a major cause of severe liver disease including chronic hepatitis, cirrhosis and hepatocellular carcinoma. The HCV burden in public health is estimated at about 71 million people worldwide by World Health Organization (WHO) with at least 400,000 people that died every year from HCV disease [1]. New hepatitis C treatments with oral direct-acting antivirals (DAAs) showing high rates of response, with short treatment duration [2] have been available.

Influence of the HCV subtype on the virological response to pegylated interferon and ribavirin therapy.

The hepatitis C virus genotype is considered to be the most important baseline predictor of a sustained virological response in patients with chronic hepatitis C treated with pegylated interferon and ribavirin. The influence of the subtype on the sustained virological response was investigated in patients infected with genotypes 1, 4, 5, or 6. This study was done on 597 patients with chronic hepatitis C who were given pegylated interferon and ribavirin for 48 weeks.

Quasispecies evolution in NS5A region of hepatitis C virus genotype 1b during interferon or combined interferon-ribavirin therapy.

Aim: To evaluate the implication of substitutions in the hepatitis C virus (HCV) non-structural 5A (NS5A) protein in the resistance of HCV during mono-interferon (IFN) or combined IFN-ribavirin (IFN-R) therapy. Although NS5A has been reported to interact with the HCV RNA-dependent RNA polymerase, NS5B, as well as with many cellular proteins, the function of NS5A in the life cycle of HCV remains unclear.

Methods: HCV quasispecies were studied by cloning and sequencing of sequential isolates from patients infected by HCV genotype 1b.

[Autoimmune thrombopenia associated with hepatitis B reactivation (reverse seroconversion) after autologous hematopoietic stem cell transplantation].

We report a case of autoimmune thrombocytopenia associated with acute reverse seroconversion of hepatitis B in a patient who was initially hepatitis B virus surface antigen negative and hepatitis B virus surface antibody positive. Reactivation occurred 9 months after chemotherapy with anti-CD 20 monoclonal antibodies and autologous hematopoietic stem cell transplantation for lymphoma had been performed. After non specific polyglobulin injections and treatment with adefovir dipivoxil, thrombocytopenia and viral replication were controlled.

Unique NS5b hepatitis C virus gene sequence consensus database is essential for standardization of genotype determinations in multicenter epidemiological studies.

A multicenter study of NS5b hepatitis C virus (HCV) genotype determination involving 12 laboratories demonstrates that any laboratory with expertise in sequencing techniques would be able to provide a reliable HCV genotype for clinical and epidemiological purposes as long as they are provided a consensus reference sequence database.

[Severe autoimmune neutropenia and thrombopenia associated with chronic C hepatitis: effect of antiviral therapy].

We report the case of a 45-year-old man admitted for severe autoimmune thrombopenia and neutropenia associated with chronic viral C hepatitis. After failed, intravenous gammaglobulin and corticosteroid therapy antiviral treatment with interferon and ribavirin was given for one year. Thrombopenia improved progressively during antiviral therapy and worsened after the end of treatment.

Usefulness of the hepatitis C virus core antigen assay for screening of a population undergoing routine medical checkup.

We studied the usefulness of the recently designed Trak-C assay for the detection and quantification of the hepatitis C virus (HCV) core antigen (Ag) for the screening of HCV infection in 4,201 subjects selected from 74,150 consecutive volunteers undergoing routine medical checkups. Subjects were selected for screening because they had risk factors (group II, n = 321) and/or elevated alanine transaminase activity (group I, n = 3847). Initially, the anti-HCV antibody assay and the Trak-C assay were performed on each patient.

Mutations within the hepatitis C virus genotype 1b E2-PePHD domain do not correlate with treatment outcome.

The hepatitis C virus (HCV) envelope protein 2 (E2) interacts in vitro with the interferon alpha (IFN-alpha)-inducible double-stranded RNA-activated protein kinase, suggesting a possible mechanism by which HCV may evade the antiviral effects of IFN-alpha. Variability in the part of the HCV E2 gene encoding the carboxy-terminal part of the protein, which includes the interaction domain (E2-PePHD), was explored in 25 patients infected with HCV genotype 1b and receiving IFN-alpha therapy. PCR products were generated and sequenced for 15 patients with a sustained response and for 10 patients with no virological response after treatment with IFN-alpha and ribavirin.

Comparison of hepatitis C virus NS5b and 5' noncoding gene sequencing methods in a multicenter study.

A national evaluation study was performed in 11 specialized laboratories with the objective of assessing their capacities to genotype hepatitis C virus (HCV) and define the applicability of a given genotyping method. The panel consisted of 14 samples positive for HCV RNA of different genotypes (including 3 samples with two different artificially mixed genotypes) and 1 HCV-negative sample. Seventeen sets of data were gathered from the 11 participating laboratories.

Subtype B human immunodeficiency virus (HIV) type 1 mutant that escapes detection in a fourth-generation immunoassay for HIV infection.

We report a case of human immunodeficiency virus (HIV) type 1 infection not detected by a highly sensitive combined antigen-antibody assay. The virus was a subtype B strain harboring a unique sequence within the immunodominant epitope of the transmembrane glycoprotein. Immunochemical analysis indicated that this sequence was probably responsible for the failure to detect HIV antibodies.

Significance of pretreatment analysis of hepatitis C virus genotype 1b hypervariable region 1 sequences to predict antiviral outcome.

The heterogeneity of hypervariable region 1 (HVR1), located at the amino terminus of the E2 envelope, may be involved in resistance to alpha interferon (IFN-alpha) treatment. We investigated whether peculiar HVR1 domain profiles before treatment were associated with the maintenance of sensitivity or the appearance of resistance to treatment. Fifteen patients infected with hepatitis C virus genotype 1b and treated with IFN with or without ribavirin were selected.