Relationship Between The Effects On Immune Balance Of Helper T Cell 1, 2(Th1/Th2) By Interleukin-18(IL-18) Level Of Newborns And Hepatitis B Virus Intrauterine Infection

ObjectiveTo study the relationship between the effects on immune balance of T helper cell 1,2(Th1/Th2) by interleukin-18(IL-18) level of newborns and hepatitis B virus infection,and to investigate the mechanism about the way of hepatitis B virus intrauterine infection.MethodsWe selected 157 full-term neonates with vaginal delivery and born by HBsAg and HBeAg postive mothers whose liver function were normal. The intrauterine infection group was consisted of 21 cases for neonates and the non-intrauterine infection group was consisted of 136 cases for neonates. The two groups of newborns were both detected for interleukin-18, interferon-γ, interleukin-4 of cord blood prior to delivery by flow cytometry.Results1. There are 3 positive for HBV-DNA, HBsAg among 21 cord blood samples. There are 18 positive for HBV-DNA or HBsAg among 21 cord blood samples.A total 21 positve for HBV serologic markers, so the newborns intrauterine infection rate of 157 HBsAg positive mothers was 13.38 %( 21/157).2. The contrast of the mean IL-18 levels of two groups: The percentage of IL-18 levels of cord blood in study group was (12.75±4.62)%, significantly lower than (14.96±4.14)% of control(t=-2.24,P<0.05).3. The contrast of mean IFN-γ, IL-4 levels of the cord blood and the percentage of IFN-γ/IL-4 of two groups: The mean cytokine IFN-γlevels of the cord blood in study group was (4.87±1.99)%, significantly lower than( 5.92±2.06)% of control (t=-2.18,P<0.05). The mean cytokine IL-4 levels of cord blood in study group was (7.45±1.41)%,higher than (7.19±1.59)% of control (t=0.68,P>0.05). The ratio of the cord blood IFN-γ/IL-4 levels of the cord blood in study group was 0.64±0.21, significantly higher than 0.89±0.37 of control (t=-3.08,P<0.05).4. The correlation between The cord blood mean IL-18 and IFN-γ, IL-4, IFN-γ/IL-4 in two groups: The positive correlation existed between IL-18 and IFN-γboth in two groups, correlation coefficient were 0.97, 0.79(both P<0.05 of two groups); the positive correlation existed between IL-18 and IL-4 both in two groups, correlation coefficient were 0.75, 0.19 (both P<0.05 of two groups); The positive correlation existed between IL-18 and the ratio of IFN-γ/IL-4 both in two groups, correlation coefficient were 0.88, 0.63(both P<0.05 of two groups).Conclusions1. HBV intrauterine infection is related to the decrease of Th1 type cell activity. The decrease of ratio of Th1/Th2 type cytokines in the cord blood and the imbalance of immune regulation of Th1/Th2 maybe the main mechanism of HBV intrauterine infection.2. HBV intrauterine infection is related to the decrease of IL-18. The effects of IL-18 on HBV intrauterine infection are through regulating the immune balance of Th1/Th2, especially through regulating the level of IFN-γ. the decrease of the cord blood IL-18 maybe one of the risk factor of HBV intrauterine infection.