The Effect Of Using Heplatitis B Immunoglobulin On The Third Trimester On The S Gene Of HBV

Objective:1,To investigate the significance of HBV genotype on mother-to-infant vertical transmission of HBV;2,To study the relationship between using HBIG in the third trimester of pregnancy and HBV S gene mutation;Method:Serum HBsAg positive gravidae with DNA titer＞1.0×10~3 copies/ml along with their newborns hospitalized in the first affiliated hospital of JiNan University from December 2006 to December 2007 were enrolled and were divided into 2 groups according to reception of HBIG (HBIG group,200IU/4 weeks im) or not(controls).Peripheral blood specimens from mothers before HBIG administration(versus controls at the first clinical visit) and antepartum,as well as from babies before vaccine immunization were sampled.ELISA was applied for hepatitis B virus markers(HBV-M) detection and fluorescent quantitative polymerase chain reaction(FQ-PCR) was for HBV DNA measured while nested PCR for augmentation of HBV S for sequencing. Compared to the standard genetic sequence in GENBANK,we analyzed genotype and S gene mutation using DNASTAR,ALIGN X soft-wares.All data were analyzed by statistical packages SPSS 13.0 for windows.Result:1.Specimens from 131 gravidae(84 in HBIG group,47 in controls) and 60 newborns were collected,in which fi'oml06 mothers and 7 babies were fulfilled S genetic sequencing.8 in 60 babies were checked with HBV DNA titer＞1.0×10~3 copies/ml.2.HBV carried by 26 in 106 mothers were genotype B while 80 were C.Numbers and percentages of genotype B and C virus carriers in HBIG group were 17(23.29%), 56(76.71%) respectively while in controls were 9(27.27%),24(72.73%).All of the 7 samples of newborns were HBV C genotype.3.As compared to standard genotype sequences in GENBANK,S gene sequencing resulted in mutations found at points of aa54,75,101,106,113,126,133,134,143,146,158,177, 182,200,210,211,250,and 257,among of which aa126,133,134,143,146 were located in "a" antigen determinant,with amino acid substitutions in most positions.4.S gene sequencing results proved no mutation that compared the compared the sequence of pregnant women before injecting HBIG with the sequence before delivery In HBIG experiment group,while compared the sequence of pregnant women when first clinical visit with the sequence before delivery In HBIG control group.5.After used HBIG,No significance was found about the HBV-DNA titer changing in 2 groups, between genotype B and C carriers.6.The homogeneity of HBV sequences between mothers and their children were 99.2%to 100%and quasispecies of HBV S gene was found in 1 pregnant woman and her newborn。7.No significance was found about the rate of neonatal HBsAb between HBIG experiment group and control group.Conclusion: 1.HBIG administered to HBsAg positive gravidae in protocol of 200IU/4 weeks during late pregnancy would not induce HBV S gene mutation.2.No significance was found on HBV genotypes for vertical transmission tendency,nor influence ofgenotypes on HBV DNA titer changing alter HBIG administration.3.The HBV S gene sequences of newborns were 99.2%～100%homogenous to their mothers' suggested that HBV in newborns were carried down from their mother.