Abstract
BACKGROUND AND AIMS: T lymphocytes play a pivotal role in resolving hepatitis B virus infection. This study aimed to investigate the dynamics of peripheral blood T lymphocyte subsets during peginterferon alpha (peg-IFN-α) therapy and their association with hepatitis B surface antigen (HBsAg) clearance in inactive HBsAg carriers (IHCs). METHODS: This prospective observational study enrolled 197 IHCs treated with peg-IFNα-2a/2b for 48 weeks and followed for 24 weeks (treatment group), and 221 IHCs who were regularly monitored for 72 weeks without treatment (IHC control group). Peripheral blood T lymphocyte subsets were evaluated using flow cytometry at baseline, and at 12, 24, 48, and 72 weeks in both groups. At 72 weeks, IHCs in the treatment group were categorized into an HBsAg clearance group and an HBsAg persistence group. Differences in T lymphocyte subsets among these groups were compared, and correlations between T lymphocyte subsets and HBsAg clearance were analyzed. RESULTS: At 72 weeks, intention-to-treat analysis showed significantly higher HBsAg clearance (46.7%) and seroconversion rates (34.5%) in the treatment group compared to the IHC control group (HBsAg clearance rate of 1.4%, seroconversion rate of 0.9%; both p < 0.001). The median absolute counts of CD3(+), CD4(+), and CD8(+) cells significantly decreased at 12, 24, and 48 weeks in both the HBsAg clearance and persistence groups, returning to baseline at 72 weeks (all p < 0.001). IHCs with HBsAg clearance had higher median percentages of CD3(+) CD8(+) cells and lower median percentages of CD3(+) CD4(+) cells and CD4(+)/CD8(+) ratios at 12, 24, and 48 weeks compared to the HBsAg persistence and IHC control groups (all p < 0.001). Baseline HBsAg levels (below 2.0 log(10) IU/mL) and hepatitis B virus DNA levels (below 20 IU/mL), alanine aminotransferase elevation at 12 weeks (greater than 2×upper limit of normal), and CD4(+)/CD8(+) ratios (less than 1.5 at 12 weeks and below 1.4 at 24 weeks) were predictive of HBsAg clearance. CONCLUSIONS: Peripheral blood CD4(+)/CD8(+) ratios at 12 and 24 weeks may serve as predictive markers for HBsAg clearance in IHCs treated with peg-IFN-α.