Mutations of hepatitis B virus S gene by hepatitis B immunoglobulin administration in late pregnancy

The safety of hepatitis B immunoglobulin (HBIG) administration in late pregnancy is still controversial, especially the hepatitis B virus (HBV) mutation-generating effects of HBIG. In order to clarify the association between HBV S gene mutations and HBIG administration in late pregnancy, 106 HBV carrier mothers and 60 newborns were recruited for the study. Peripheral blood specimens were collected from mothers before HBIG administration and delivery, as well as from newborns before vaccine immunization. HBV-DNA was detected by fluorescent quantitative-polymerase chain reaction (PCR). HBV S gene was amplified by nested PCR and then directly sequenced. Compared with nucleotide sequences and amino acids in HBV S gene of 73 cases in HBIG group, there were no changes after HBIG injection until delivery. The rate of the mothers infected with genotype C was significantly higher than mothers with genotype B (75.47% vs. 24.53%; P < 0.05). Seven of sixty neonates obtained the results of sequencing. All of the seven newborns were genotype C. But HBV genotypes were not significantly different in HBV intrauterine transmission (P > 0.05). Injection of HBIG does not cause mutations of HBV S gene in Chinese pregnant women. HBV genotypes are not the main factors to intrauterine transmission.