Objective: To explore the susceptibility of children to develop intrauterine hepatitis B virus (HBV) infection through studying the association between interferon gamma (IFN-gamma) + 874 single nucleotide polymorphism (SNP) and intrauterine HBV infection.
Methods: The subjects were selected from outpatients who were in our hepatitis B (HB) vaccine following-up clinics. The subjects whose mothers were HBV carriers were inoculated with HB vaccine or HB vaccine and hepatitis B immunoglobulin (HBIg). Intrauterine HBV infection was defined as peripheral blood HBsAg and/or HBV-DNA positive at birth and lasting for six months (group I). Normal immune children were defined as peripheral blood negative for HBV marker since birth and afterwards HBsAb titers were above protective level (group II). The subjects were composed of the following two groups. Group I consisted of 46 children with intrauterine HBV infection. Group II was composed of 73 normal children. A Taqman fluorescence polymerase chain reaction for the IFN-gamma + 874 SNP was performed for both groups.
Results: IFN-gamma + 874 SNP was tested successfully for every subject. Frequencies of AA, AT and TT genotype were 67.4%, 19.6% and 13.0% in the intrauterine HBV infection group, and 45.2%, 30.1% and 24.7% in the normal immune children group. A significant difference was found in the frequency distribution of IFN-gamma + 874 genotype between the two groups (chi(2) = 5.102, P = 0.02389). In the intrauterine HBV infection group the AA genotype was more common than in normal immune group.
Conclusion: There is an association between IFN-gamma + 874 SNP and intrauterine HBV infection. This study suggested the possibility that IFN-gamma + 874 SNP might be important in determining an individual's susceptibility to development of intrauterine HBV infection.