Hepatitis B virus kinetics under antiviral therapy sheds light on differences in hepatitis B e antigen positive and negative infections.

BACKGROUND: Hepatitis B e antigen (HBeAg)­negative chronic hepatitis B infection has a presentation and clinical course that is divergent from that of HBeAg­positive infection. The former usually presents with lower viral levels but faster progression to liver disease. We sought to better understand the balance between replication and the immune response against hepatitis B virus (HBV). METHODS: Viral kinetics in 50 HBeAg­negative patients under various treatment protocols with interferon α and/or nucleoside or nucleotide analogs was analyzed. HBV DNA level was measured frequently and the data fitted to a viral dynamic model. A meta­analysis of all published studies of viral kinetics in HBeAg­positive and HBeAg­negative infection was also conducted. RESULTS: We found that the clearance of both HBV virions and infected cells was significantly faster in HBeAg­negative infection than in HBeAg­positive infection. In HBeAg­negative infection, there was also a negative correlation between baseline HBV DNA levels and infected cell half­life, suggesting that the higher the viral load the faster the turnover of infected cells. CONCLUSIONS: These results reveal the dual role played by the immune response in maintaining lower viral levels and inducing faster turnover of infected cells, the latter of which may be responsible for the more aggressive nature of HBeAg­negative infection.

Dynamic range of hepatitis C virus RNA quantification with the Cobas Ampliprep-Cobas Amplicor HCV Monitor v2.0 assay.

Accurate quantification of hepatitis C virus (HCV) RNA is needed in clinical practice to decide whether to continue or stop pegylated interferon-alpha-ribavirin combination therapy at week 12 of treatment for patients with chronic hepatitis C. Currently the HCV RNA quantification assay most widely used worldwide is the Amplicor HCV Monitor v2.0 assay (Roche Molecular Systems, Pleasanton, Calif.). The HCV RNA extraction step can be automated in the Cobas Ampliprep device. In this work, we show that the dynamic range of HCV RNA quantification of the Cobas Ampliprep/Cobas Amplicor HCV Monitor v2.0 procedure is 600 to 200,000 HCV RNA IU/ml (2.8 to 5.3 log IU/ml), which does not cover the full range of HCV RNA levels in infected patients. Any sample containing more than 200,000 IU/ml (5.3 log IU/ml) must thus be retested after dilution for accurate quantification. These results emphasize the need for commercial HCV RNA quantification assays with a broader range of linear quantification, such as real-time PCR-based assays.

HIV and hepatitis C virus RNA in seronegative organ and tissue donors.

The objective of our study was to determine whether nucleic acid testing could detect HIV RNA or hepatitis C virus (HCV) RNA in a large series of seronegative organ and tissue donors, and whether this technique should be routinely used to improve viral safety of grafts. We studied 2236 organ donors, 636 tissue donors, and 177 cornea donors. We identified five HCV RNA-positive donors in 2119 HCV-seronegative organ donors, and one HCV RNA-positive donor in 631 HCV-seronegative tissue donors. No HIV-seronegative, HIV RNA-positive donor was identified. Our data suggest that routine nucleic acid testing of organ and tissue donors might increase viral safety in transplantation.

Multicenter quality control for the detection of hepatitis C virus RNA in seminal plasma specimens.

The discrepant results available in the literature about the presence of hepatitis C virus (HCV) RNA in seminal plasma of men chronically infected by this agent are related, at least in part, to the molecular techniques used and particularly to the wide range of protocols dedicated to RNA extraction. In order to evaluate these protocols and to standardize the method of detection of HCV RNA in this fluid, a panel of coded specimens was tested blindly in 12 French laboratories; it included 14 seminal plasma specimens and four water controls spiked with HCV RNA ranging from 10 to 20000 IU/ml and two HCV-negative seminal plasma specimens. The extraction step was performed according to methods using either silica beads (NucliSens [Organon Teknika S.A., Fresnes, France]; RNA viral kit [Qiagen, Courtaboeuf, France]) or guanidinium thiocyanate (Amplicor HCV assay; Roche Diagnostics, Meylan, France), preceded or not by a centrifugation of the seminal plasma. For the amplification step, all the laboratories performed the same reverse transcription-PCR technique (Amplicor HCV Cobas assay). The percentage of correct results ranged from 53.3 to 100, the poorest results being obtained when no centrifugation step preceded the Amplicor extraction protocol. The rate of correct results was significantly higher in laboratories using a preliminary centrifugation of the specimen (P = 0.034 by chi-square test). By contrast, the overall number of correct results was not correlated to the initial volume of sample used for the test. These results allowed us to validate standardized techniques adapted to the performance of this test on a routine basis, especially in men infected with HCV and involved in programs of medically assisted reproduction.