BACKGROUNDB-cell may participate in the cellular immune process of hepatitis B antigen clearance. However, the function and specific mechanism of B-cell during interferon-pegylated interferon α-2a (Peg-IFN-α) treatment in chronic hepatitis B (CHB) patients have not yet been described.METHODSA total of 150 CHB patients enrolled in this study, who received 48 weeks of Peg-IFN α treatment. The differentiation clusters CD19, CD24, CD27, CD38, CD40, and CD80 of B cell surface markers in CHB patients were detected by flow cytometry. Spearman correlation and Logistic regression analysis were performed for the analysis.RESULTSThe clearance rate of HBsAg increased significantly with the duration of Peg-IFN-α treatment, reaching 32.2% by 48 weeks. During the Peg-IFN-α therapy, the frequency of B-cell and its subsets increased significantly. However, we did not observe any significant difference in the frequency of the B-cell and its subsets in patients with or without HBsAg clearance after 48 weeks Peg-IFN-α treatment. The change in HBsAg value was negatively related to the change in plasmablasts (CD19+CD38+) level before and after 48 weeks treatment (r = -0.326, p = 0.006). Moreover, the results showed that HBsAg <288.70 IU/mL at baseline and HBsAg <58.05 IU/mL at 12 weeks were strong predictors of HBsAg clearance in patients with 48 weeks Peg-IFN-α treatment.CONCLUSIONThe remodeling of B cell subsets, especially plasmablasts (CD19+CD38+), during Peg-IFN-α treatment was closed associated with the clearance of hepatitis B antigen.