Serum hepatitis B virus markers reflect intrahepatic covalently closed circular DNA and transcriptional activity across chronic hepatitis B phases

BACKGROUND Covalently closed circular DNA (cccDNA) maintains hepatitis B virus (HBV) persistence through its transcriptional activity.While cccDNA and pregenomic RNA (pgRNA) are central to HBV replication, serum markers reflecting active cccDNA remain poorly defined across the phases of chronic hepatitis B (CHB).AIM To identify serum markers reflecting intrahepatic cccDNA and its activity, we analyzed a large CHB cohort encompassing all immunological phases.METHODS Samples from 406 treatment-naïve CHB patients were analyzed by disease phase, including 56 hepatitis B e antigen (HBeAg)-positive chronic HBV infection (EPCI), 153 HBeAg-positive-chronic hepatitis B (EPCH), 83 HBeAg-negative chronic HBV infection (ENCI), and 114 HBeAg-negative chronic hepatitis B (ENCH).Serum markers [hepatitis B surface antigen (HBsAg), hepatitis B core-related antigen (HBcrAg), and HBV RNA]and intrahepatic markers (cccDNA and pgRNA) were quantified with commercial assays.Transcriptional activity was evaluated in patients with comparable intrahepatic cccDNA levels. RESULTSAll serum and intrahepatic markers were inversely associated with age and were higher in HBeAg-positive than in HBeAg-negative patients.Correlations among serum and intrahepatic markers appeared higher in HBeAg-positive patients.Serum markers correlated more closely with pgRNA than with cccDNA.Serum HBcrAg and HBV RNA better reflected intrahepatic markers than HBsAg.Among 120 patients with comparable 5 / 34 cccDNA levels, intrahepatic cccDNA transcriptional activity (pgRNA/cccDNA) varied across CHB phases: Highest in EPCI, lowest in ENCI, moderate in EPCH, and reelevated in ENCH.HBcrAg and HBV RNA showed stronger associations with cccDNA transcriptional activity than HBsAg across the EPCH and ENCH phases.Notably, no serum marker reliably reflected pgRNA or transcriptional activity in the ENCI phase. CONCLUSIONHBcrAg and HBV RNA are phase-dependent surrogates of transcriptionally active cccDNA.The lack of reliable markers in ENCI highlights its virologic heterogeneity.These findings support phase-specific monitoring and treatment decisions.