Hepatitis B post-partum e antigen clearance in hepatitis B carrier mothers: Correlation with viral characteristics

Background: The purpose of the present paper was to correlate hepatitis B virus (HBV) genotype, e antigen titer, HBV-DNA level and precore/basal core promoter mutations with post-partum e antigen clearance in hepatitis B e antigen (HBeAg)-positive carrier mothers. Methods: A total of 40 consecutive HBeAg-positive carrier mothers were studied from January 2002 to January 2003. The blood samples were taken at delivery, 3-4 months and at 1 year after delivery, and the follow-up period was until 1 year after delivery. All sera were assayed for HBeAg, HBV-DNA level, HBV genotype and precore/basal core promoter mutations. The correlation between HBV characteristics and post-partum e antigen clearance was analyzed by Mann-Whitney, Pearson chi(2) and multiple logistic regression tests. Results: The mean age of the 40 HBeAg-positive carrier mothers was 29.9 +/- 5.3 years with a mean parity of 1.4 +/- 0.7. Five of them (group I) had post-partum e antigen clearance, which persisted thereafter, whereas the remaining 35 carrier mothers (group II) had persistent positivity of HBeAg during the follow-up period. The prepartum comparisons of HBV characteristics between groups I and II were comparable in terms of demographics and distributions of HBV genotype and precore/basal core promoter mutations. In contrast, group I carrier mothers had lower HBeAg titer and HBV-DNA level than group II carrier mothers (1:80 vs 1:4000, P = 0.02, and 3.75 x 10(5) vs 3 x 10(8) copies/mL, P = 0.028, respectively). Conclusions: Post-partum e antigen clearance in HBeAg-positive carrier mothers is closely associated with prepartum low HBeAg titer or HBV-DNA level.