Changes of serum HBsAg level under antiviral therapies and the possible impacts of HBV genotypes B and C:A pilot study

Objectives To observe the changes of serum HBsAg under antiviral therapies in chronic hepatitis B patients,and the influences of HBV genotypes B/C on the changes. Methods 47 patients treated with adefovir and 33 with peg-interferon-α2a were studied. Abbott Architect HBsAg assay was used to quantify serum HBsAg in serial samples collected at baseline,treatment week 12,24 and 48. Direct sequencing of PCR fragments covered HBV nt1650-nt2065 was adopted to determine genotypes of hepatitis B virus. Plasmids contained 1.24 unit HBV genome(genotype Ae,Ba,C and D)were transfected into Huh7 cells and interferon-α2a(1500Iu/ml)was then added to culture medium,supernatants and cell lysates were collected after 72 hours and HBsAg quantification was performed. Results Both adefovir and peg-interferon-α2a reduced serum HBsAg levels at treatment week 12 to 59.8% and 53.6% compared to baseline(P=0.005 and 0.001,respectively). Reductions of HBsAg from treatment week 12 to 24 were not significant in both adefovir and peg-interferon-α2a groups(P=0.055 and 0.067,respectively),and the median change values of HBsAg from week 12 to 24 were just 11.2% and 9.2% of these counterpart values from baseline to week 12. In adefovir treatment groups,HBsAg was reduced to 39.4% in genotype B and 61.6% in genotype C patients during first 12 treatment weeks(P=0.092);in peg-interferon-α2a group,HBsAg was reduced to 32.6% for genotype B and 54.7% for type C,and was not different either(P=0.174). Comparing to interferon blank plates,HBsAg in the supernatants was reduced to 36.9% or lower,and no difference was found among these four genotypes(P=0.223);intracellular HBsAg was also reduced to at least 60.5%,and there was no difference found either(P=0.877). Conclusions Both adefovir and peg-interferon-α2a can decrease serum HBsAg levels,and the reductions in the first 12 treatment weeks were predominant. But the reductions has no association with HBV genotypes B/C.