BACKGROUNDWe 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.

METHODSFifty-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.

RESULTSThe 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 log10kU/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.

CONCLUSIONSEffective 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.