Institute of Digestive Disease, The Chinese University of Hong Kong, Hong Kong.
Kinetics of serum hepatitis B surface antigen (HBsAg) level in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B patients presented with severe reactivation and received oral antiviral therapy is unknown. We aimed to investigate the kinetics of HBsAg level among these patients.
HBeAg-negative patients on antiviral therapy with follow-up for 2 years were studied. Those presented with severe reactivation (alanine aminotransferase [ALT] ≥5 times of normal) were compared to those with mild hepatitis. Serum HBsAg level was measured by Elecsys HBsAg II Quant assay (Roche) at baseline and 6-monthly.
Total 192 (74 severe reactivation) patients were studied. Eighty-one (42%), 74 (39%) and 37 (19%) patients were on lamivudine, entecavir and telbivudine, respectively. Forty-four (23%) patients had early HBsAg decline, i.e. ≥0.5log10 reduction, at month 6. Patients with severe reactivation had higher serum baseline ALT (1415±897 vs. 73±39 IU/l), HBV DNA (6.4±1.6 vs. 5.2±1.2 log10 IU/ml) and HBsAg (3.3±1.0 vs. 2.9±0.6 log10 IU/ml), as more early HBsAg decline (50% vs. 6%) (all P<0.001) than those without. The HBsAg change of patients with severe reactivation was higher at month 0-6 (-0.58±-1.26 vs. -0.01±-0.26 log10 IU/ml; P<0.001) but then became comparable from month 6-24 (-0.19±-0.60 vs. -0.13±-0.19 log10 IU/ml; P=0.85), compared to those presented with mild hepatitis.
Patients presented with severe reactivation of HBeAg-negative hepatitis more likely develop early HBsAg decline during antiviral therapy. It may indicate a transient strong immune clearance with rapid initial reduction in serum HBsAg, which cannot be sustained as a faster clearance of serum HBsAg.