Relationship Of IFN-γ Gene Polymorphism With Susceptibility To Intrauterine HBV Infection

Objective: To explore the susceptibility of children to develop intrauterine hepatitis B virus (HBV) infection through studying the relationship between IFN-γ gene polymorphism (including IFN-γ +874A/T single nucleotide polymorphism and CA short tandem repeat polymorphism ) and intrauterine HBV infection.Sbujects and methods:1. The subjects were selected from outpatients who were in our hepatitis B (HB) vaccine following-up clinics. These subjects whose mothers were HBV carriers were inoculated with HB vaccine or HB vaccine and hepatitis B immunoglobulin (HBIg) on procedure. Intrauterine HBV infection children were defined that peripherial blood were HBsAg and/or HBV-DNA positive at birth and lasting for six months(group). Normal immune children were defined that peripherial blood were negative for HBV marker since birth and afterwards HBsAb titers were above protective level (group).The controls were from inpatients who were acute respiratory infection children. All subjects were normal with liver function.2. A TaqMan fluorescence polymerase chain reaction in the IFN- Y +874A/T single nucleotide polymorphism was tested in all subjects. Capillary electrophoresis in the IFN-γ CA microsatellite was assayed.Results:1. 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 respectively.A significant difference was found inthe frequency distribution of IFN- y +874 genotype between two groups(X2=5. 102, P=0. 02389).In the intrauterine HBV infection group the AA genotype was more common than normal immune group.2. Frequency of IFN +874A biallelic was 77.17% in the intrauterine HBV infection group, and 60.27% in the normal immune children group. In the intrauterine HBV infection group the IFN +874A biallelic was more common than normal immune group. A significant difference was found in the frequency distribution between two groups(X2=7. 238, P=0. 02389,OR=2. 228, 95%CI 1.244-3.992).3. (CA12)/(CA12)+ of IFN CA microsatellite polymorphism was 11.90% in the intrauterine HBV infection group, and 26.47% in the normal immune children group. A significant difference was found in the frequency distribution between two groups(X2=5. 64, P=0.0176).4. Frequency of IFN- y CA repeat 12 times was 25% in the intrauterine HBV infection group, and 43.38% in the normal immune children group. In the intrauterine HBV infection group the frequency of IFN CA repeat 12 times was more less than normal immune group. A significant difference was found in the frequency distribution between two groups(X2=7. 548, P=0. 0060).Conclusion:1. There is an relationship between IFN +874A/T SNP and intrauterine HBV infection. In the intrauterine HBV infection group the AA genotype was more common than normal immune group, and the IFN- y+874A biallelic was more common than normal immune group.2. There is an relationship between IFN CA microsatellite polymorphism and intrauterine HBV infection. In the intrauterine HBV infection group the frequency of IFN- y CA repeat 12 times was more less than normal immune group.3. This study suggested the possibility that IFN gene polymorphism might be important in determining an individual's susceptibility to development of intrauterine HBV infection.