Changes of serum hepatitis B surface antigen level in HBeAg positive chronic hepatitis B patients at the twelth week of lamivudine treatment:relations to hepatitis B virus genotypes

Objective To investigate the characteristics of serum hepatitis B surface antigen(HBsAg) changes,and on which the possible influences of Hepatitis B virus(HBV) genotypes have,at initial stage of lamivudine treatment in hepatitis B e antigen(HBeAg) positive chronic hepatitis B patients.Methods 87 patients who were HBeAg positive and naive to antiviral therapy prior to lamivudine treatment were studied.Abbott Architect HBsAg assay was used for quantification of serum HBsAg levels at treatment baseline and week 12.HBV genotypes were determined with polymerase chain reaction combined with restriction fragment length polymorphism.Results Serum HBV DNA levels in all patients were decreased from baseline to week 12 with a range of 0.75-7.80(log10 copies/ml,median value was 4.31,P0.001),and collectively serum HBsAg was reduced to 57.99% taken baseline as 1.0(P0.001).However conspicuouse serum HBsAg reductions were only found in patients with HBV genotype B(HBV/B,n=43,P0.001) but not in genotype C(HBV/C,n=43,P=0.378).Positive correlation was found between changes of serum HBsAg from baseline to week 12 and those of serum HBV DNA(Rs=0.341,P=0.002,n=87),which seemed 'stronger'(Rs=0.577,P0.001) in HBV/B patients but 'disappeared'(Rs=0.068,P=0.686) in HBV/C patients.Along with HBV DNA levels decreasing from treatment baseline to week 12,reductions of serum HBsAg was not achieved in 32.2%(n=29) patients,which were determined by low levels of serum HBsAg at baseline(odds ratio was 0.387 and 95% confidence interval was 0.188-0.794,P=0.010) and infection with HBV/C(odds ratio was 4.083 and 95% confidence interval was 1.362-12.236,P=0.012).Conclusion Serum HBsAg in some patients was not decreased along with HBV DNA under 12 weeks lamivudine treatment,on which HBV/C infection and low levels of baseline serum HBsAg had determinant affects.