[Development and validation of a specific method for relative HBV-genotype G (G-HBV) quantification in the context of co-infection with other genotypes]. / Co-infection par le VHB de génotype G : développement, validation et application d'une technique de quantification spécifique du VHB de génotype G.

GOAL OF THE STUDY: A detection and quantification method specific of genotype G hepatitis B virus (G-HBV) was developed and used to study the epidemiology and evolution of G-HBV co-infection during antiviral therapy. PATIENTS AND METHODS: A multiplex real time PCR was developed and validated on A-HBV and G-HBV plasmid mixes. G-HBV infection was sought for on chronic hepatitis B carriers followed in our institution. RESULTS: Two primers, flanking the specific G-HBV 36 nucleotide insertion and two probes, including one specific for the insertion, were validated for a multiplex real time PCR. This new tool was well correlated to commercially available quantification systems within a 2 to 7 log(10) IU/mL range. On A- and G-HBV clonal mixes, G-HBV was quantified with a precision between 5 to 10%. On HBV-HIV infected patients, a 25% G-HBV prevalence was found, while it was below 1% in HBV mono-infected patients. Longitudinal G-HBV quantifications on five treated patients indicate that G-HBV is not selected by antiviral treatment. CONCLUSION: A specific method for G-HBV quantification within multi-genotype mixes was set up. The important G-HBV prevalence in HIV patients was unexpected. Our data are not in favour of an intrinsic resistance of G-HBV to current antivirals.