Evidence of Residual Ongoing Viral Replication in Chronic Hepatitis B Patients Successfully Treated with Nucleos(t)ide Analogues


 
 
 Chronic hepatitis B is usually treated with nucleos(t)ide analogues (NAs). However, a cure is rarely achieved even with years of treatment. Here, we investigated whether viral replication is completely halted and how long covalently closed circular DNA (cccDNA) persists in NAs successfully treated patients.
 
 
 
 A series of longitudinal serum samples and a collection of cross-sectional liver biopsies were obtained from NAs successfully treated patients. Viral variants in serum HBV RNA were enumerated by deep sequencing. Viral replication intermediates in hepatocytes were directly visualized by in situ hybridization. The apparent half-life of each cccDNA was estimated.
 
 
 
 Three out of six successfully treated patients demonstrated clear evidence of a small proportion of virus evolution, although the overwhelming variants were identical or possessed a similar degree of divergence through time. The apparent half-life of variants was estimated from approximately 7.42 weeks to infinite. Moreover, hepatocytes remained positive for cytoplasmic nucleocapsids-associated relaxed circular DNA (rcDNA) in four out of seven liver needle biopsies.
 
 
 
 We therefore conclude that even after prolonged treatment, a small proportion of the cccDNA reservoir is constantly replenished by continued low-level HBV replication, whereas the greatest amount of cccDNA reservoir persists over time.
