Effects of pegylated interferon on T cell receptor fingerprints in chronic hepatitis B patients with/without surface antigen clearance

BACKGROUND Chronic hepatitis B (CHB) remains a critical global health challenge, with few patients achieving spontaneous clearance of hepatitis B surface antigen (HBsAg), which is a key indicator of functional cure. T cell plays an important role in HBsAg clearance. AIM To compare T cell receptor (TCR) fingerprints between patients with or without HBsAg clearance after pegylated interferon alpha-2b (PegIFNα-2b) added on nucleos(t)ide analogues (NAs). METHODS In this observational study, peripheral blood mononuclear cells (PBMCs) were isolated from six comparable CHB patients who achieved HBsAg clearance (Group-C) or not (Group-NC) after 48 weeks of PegIFNα-2b added to NA therapy. Patients in Group-C and Group-NC had comparable age, gender, baseline hepatitis B virus (HBV) DNA, HBsAg, hepatitis B envelop antigen (HBeAg), total bilirubin, alanine aminotransferase (ALT) and cirrhosis status. All patients had received at least one year of NA before PegIFNα-2b therapy. TCR repertoire profiles (fingerprints) were screened and compared by RNA sequencing and bioinformation analysis between the two groups. RESULTS Six male patients without cirrhosis were enrolled in this study, with three patients in each group. 200 ng of RNA from each PBMC sample was extracted for standard RNA sequencing for construction of a complementary DNA library. Baseline levels of HBsAg, HBeAg, HBV DNA (< 50 IU/mL) and ALT prior to PegIFNα-2b therapy showed no statistic differences between the two groups (P > 0.05). It was found that compared to Group-NC, Group-C had significantly higher TCR diversity in both α and β chain, including more unique clonotypes (P = 0.017, P = 0.038 respectively), more repertoire overlap (P = 0.002, P = 0.002 respectively), a broader complementarity-determining region3 length distribution, and higher Chao1 index (P = 0.016, P = 0.048 respectively). CONCLUSION Patients with HBsAg clearance had a more diverse and robust T cell response, which may correlate with HBsAg clearance status. These immune signatures may serve as potential reference indicators for PegIFNα-2b treatment response in CHB patients.