A greater frequency of circulating CCR7loPD-1hi follicular helper T cells indicates a durable clinical cure after Peg IFN-α therapy in chronic hepatitis B patients.

Background: Emerging evidence indicates that the treatment duration of pegylated interferon-α and HBsAb may predict relapse in chronic hepatitis B (CHB) patients who achieved clinical cure. However, the host immunological mechanisms contributing to clinical relapse remain poorly characterized.

Objectives: This study aimed to identify the immunological factors associated with relapse in chronic hepatitis B (CHB) patients who achieved clinical cure based on pegylated interferon-alpha treatment.

Methods: CHB patients who achieved HBsAg loss after discontinuing pegylated interferon-alpha therapy were enrolled and followed up for at least 96 weeks. HBcrAg and immunological markers, including the proportion of follicular helper T (Tfh) cells were assessed by flow cytometry. Peripheral blood cytokine levels were measured using a Luminex assay. The primary outcome was the correlation between immunological markers with relapse at the end of treatment (EOT) and end of follow-up (EOF).

Results: A total of 456 CHB patients were included. During the 96-week follow-up period, 37 patients (8.11%) experienced a relapse. Propensity score matching was performed at a 1:2 ratio, resulting in the inclusion of 37 relapsed (R) and 74 non-relapsed (NR) patients. The NR group exhibited higher proportions of Tfh cells than the R group in both EOT and EOF (EOT: 12.52% vs. 8.78%, p=0.008; EOF: 11.38% vs. 8.29%, p=0.008). A significantly greater proportion of CCR7loPD-1hi Tfh cells was observed in the NR group at the EOT (9.4% vs. 4.5%, p=0.009). The frequency of CCR7loPD-1hi Tfh cells was significantly and positively correlated with anti-HB levels in EOT (p=0.015, r=0.392). Serum levels (median, pg/mL) of CTLA-4 (EOT: 14.87 vs. 7.84; EOF: 14.87 vs. 7.97), PD-1 (EOT: 321.44 vs. 203.96; EOF: 288.45 vs. 166.04), and TIM-3 (EOT:4487 vs. 21254; EOF:2973 vs. 1768) were significantly higher in the R group than in the NR group at both EOT and EOF (p<0.05). At EOT, the HBcrAg level was significantly greater in the R than in the NR group (3.45±0.94 vs. 2.63±0.80 log10 U/mL, p=0.003).

Conclusions: Higher frequencies of CCR7loPD-1hi Tfh cells, lower levels of sCTLA-4 as well as sPD-1 in EOT were protective factors for relapse among CHB patients who experienced HBsAg loss after pegylated interferon-alpha therapy. CCR7loPD-1hiTfh cells produced insufficient IL-21 in patients who experienced recurrent disease, which resulted in a decrease in the ability of B cells to produce anti-HBs.