Quantification of intrahepatic total HBV DNA in liver biopsies of HBV-infected patients by a modified version of COBAS® Ampliprep/COBAS®TaqMan HBV test v2.0

Abstract

Intrahepatic total HBV DNA (it-HBV DNA) level might reflect the size of virus reservoir and correlate with the histological status of the liver. To quantitate it-HBV DNA in a series of 70 liver biopsies obtained from hepatitis B chronic patients, a modified version of the COBAS®Ampliprep/COBAS®TaqMan HBV test v2.0 was used for this purpose. The linearity and reproducibility of the modified protocol was tested by quantifying serial dilutions of a full-length HBV containing plasmid and it-HBV DNA from a reference patient. A good linear trend between the expected values and those generated by the assay was observed at different concentrations of both plasmid and reference patient (R 2=0.994 and 0.962, respectively). Differences between the values obtained in two independent runs were ≤0.3 log IU for the plasmid and ≤0.6 log IU/mg for the reference patient, showing a high inter-run reproducibility. In the 70 liver biopsies, it-HBV DNA level ranged from 1.4 to 5.4log IU/mg, with a good linearity and reproducibility between the values obtained in two runs [R 2=0.981; median (IQR) difference of it-HBV DNA 0.05 (0.02-0.09) IU/mg]. The modified COBAS®Ampliprep/COBAS®TaqMan HBV test v2.0 allows an accurate quantitation of it-HBV DNA. Its determination may have prognostic value and may be a useful tool for the new therapeutic strategies aimed at eradicating the HBV infection.