The association of the heterogeneity of HBV reverse transcriptase quasispecies with antiviral efficacy after treatment with nucleos(t)ide analogues for 10 years.

To assess the heterogeneity of HBV reverse transcriptase (RT) quasispecies during 10 years of antiviral therapy and their association with antiviral efficacy. Nineteen patients with chronic hepatitis B (CHB) infection receiving nucleos(t)ide analogues (NAs) were enrolled. Based on the antiviral efficacy after 1 year of treatment, 5 patients were grouped into an early virologic response (EVR) group, while 8 patients were grouped into a late virologic response (LVR) group. Furthermore, 6 CHB patients that had undergone antiviral treatment for 10 years were grouped into a virologic breakthrough (VBT) group. The HBV RT from each patient were amplified, cloned, and sequenced. The complexity of the RT gene in the EVR group was significantly higher than that in the LVR (P = 0.0393) and VBT groups (P = 0.0141). Phylogenetic tree analysis showed that the average branch length of the EVR and LVR groups were significantly greater than that of VBT group (P < 0.001). The complexity (at the nucleotide level) of the RT quasispecies was negatively correlated with the corresponding HBV DNA load (P = 0.0163) at one year post-antiviral treatment. Moreover, both the LVR and VBT groups accumulated more deleterious mutations than the EVR group. After 1 year of NAs treatment, the increased HBV quasispecies complexity and evolutionary topologies, coupled with less deleterious mutations, are likely associated with a favorable efficacy during long-term antiviral treatment.