HBcrAg Identifies Patients Failing to Achieve HBeAg Seroconversion Treated with Pegylated Interferon Alfa-2b

BACKGROUND: We aimed to evaluate the usefulness of serum hepatitis B virus core-related antigens (HBcrAg) for predicting hepatitis B e antigen (HBeAg) seroconversion in HBeAg-positive chronic hepatitis B patients treated with conventional interferon (IFN) alfa-2b or pegylated IFN. METHODS: Fifty-eight patients were enrolled: 29 for the training group and 29 for the validating group. HBcrAg was measured at baseline, week 12, end of the treatment, and 12- and 24-week follow-ups. Sixteen patients in the training group were enrolled in the long-term follow-up (LTFU), during which time the dynamics of the HBcrAg was monitored. RESULTS: The serum HBcrAg level gradually declined during treatment among the HBeAg seroconversion patients of the training group (from baseline, week 12, end of the treatment, 12-week follow-up to 24-week follow-up were 110,245 kU/ml, 3760 kU/ml, 7410 kU/ml, 715 kU/ml, 200 kU/ml, respectively). HBcrAg <19,565 kU/ml at week 24, HBcrAg <34,225 kU/ml at 12-week follow-up, and HBcrAg decrease ≥0.565 log(10) kU/ml from the baseline to the end of treatment (EOT) had negative predictive values (NPVs) of 100% for HBeAg seroconversion at the end of follow-up, whereas the positive predictive values (PPVs) were 30.77%, 26.67%, and 25.00%, respectively. The patients with HBeAg seroconversion at the end of 24-week follow-up remained in seroconversion during the LTFU, during which time their serum HBcrAg levels steadily declined or even became undetectable, ranging from 0 to 2.1 kU/ml. CONCLUSIONS: Effective antiviral treatment can decrease HBcrAg levels in the serum. The NPVs of HBcrAg for predicting HBeAg seroconversion at 24-week follow-up was 100%, but the PPVs were not satisfactory (all <31%). The serum HBcrAg levels of the patients with HBeAg seroconversion at the end of the 24-week follow-up steadily declined or even became undetectable during the LTFU.