NK cell reconfiguration and cytokine dynamics during pegylated interferon-α and nucleos(t)ide analogs combination therapy in chronic hepatitis B

HBsAg loss remains a major challenge in chronic hepatitis B (CHB). This study aimed to characterize the dynamic changes in NK cell phenotypes, receptor expression, and cytokine profiles during pegylated interferon-α (PEG-IFNα) and nucleos(t)ide analogs (NAs) combination therapy and their association with clinical outcomes. Twenty-seven CHB patients receiving PEG-IFNα and NAs combination therapy were stratified into on-treatment HBsAg loss group (HBsAg < 0.05 IU/mL, n = 10) and non-HBsAg loss group ( n = 17) at week 48. Flow cytometry assessed NK cell subsets (CD56 bright , CD56 dim ) and receptor expression (NKG2D, NKp30, NKp46, KIR, NKG2A, TIM3). Serum cytokines (IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10) were measured by ELISA. Correlations of virological markers with NK cell subsets/receptors or cytokines were analyzed. PEG-IFNα and NAs combination therapy expanded CD56 bright NK cells while reducing CD56 dim subsets in both on-treatment HBsAg loss and non-HBsAg loss groups. In the on-treatment HBsAg loss group, persistent KIR upregulation was observed in CD56 bright NK cells, whereas CD56 dim NK cells maintained elevated NKG2A expression. Cytokine analysis showed that the on-treatment HBsAg loss group exhibited significantly lower serum levels of pro-inflammatory cytokines (IFN-γ, TNF-α, IL-6, and IL-2), while maintaining higher levels of the anti-inflammatory cytokine IL-10. Correlation analysis revealed significant inverse correlations between HBsAg and CD56 bright NK cell proportion/ receptor expression, whereas HBsAg correlated positively with CD56 dim NK cell frequency in on-treatment HBsAg loss group. Moreover, HBsAg was positively correlated with pro-inflammatory cytokine levels in both treatment groups. PEG-IFNα and NAs combination therapy is associated with on-treatment HBsAg loss at week 48, potentially through optimizing cytokine responses, regulating NK cell balance (CD56 bright /CD56 dim ) and related receptors. Study limitations include the single-center design and moderate sample size. MR-53-26-076931 Date of registration: 31 August 2026. Full name of the registry in the national medical research registration information system:Prediction of clinical curative effect of pegylated interferon a individualized intermittent treatment of nucleoside (acid) in patients with hepatitis B.