[Role of TLR 9 expression in maternal peripheral blood and placenta in intrauterine transmission of HBV]

Objective: To explore the role of TLR 9 in intrauterine transmission of hepatitis B virus (HBV) through blood pathway and placenta. Methods: Epidemiological investigation was carried out in 290 HBsAg positive parturients and 45 normal parturients (control group) in Northwest Women and Children Hospital of Shaanxi Province. Enzyme-linked immunosorbent assay (ELISA) was used to detect five serological makers of hepatitis B and TLR 9 levels in peripheral blood of pregnant women and newborns. HBV DNA was detected by real-time fluorescence quantitative PCR. Detection of TLR 9 expression in placenta by immunohistochemical method. A case-control study was conducted to analyze the difference of TLR 9 levels in placenta and peripheral blood of HBsAg- positive pregnant women with intrauterine transmission of HBV. Results: The incidence of dominant HBV infection (DBI), occult HBV infection (OBI) and intrauterine transmission of HBV were 9.28 % (27/291), 40.21 % (117/291) and 49.48 % (144/291) respectively. (1) The level of TLR 9 in peripheral blood of HBsAg-positive parturients, non-HBV intrauterine transmission (NBIT) group and OBI group were significantly lower than that of control group ( P <0.001). The level of TLR 9 in DBI group was significantly higher than those in NBIT group and OBI group ( P =0.000). (2) The TLR 9 level in HBeAg-negative group was significantly lower than that in HBeAg-positive parturients in OBI group ( P =0.01). (3) With the increased severity of intrauterine transmission of HBV in each HBV DNA load group, the TLR 9 level in maternal peripheral blood increased significantly ( P <0.05). (4) With the increased severity of intrauterine transmission of HBV, the levels of TLR 9 increased significantly in antiviral therapy, immunoglobulin injection and non-hepatitis B vaccine groups ( P <0.05). (5) The expression of TLR 9 in placenta tissues with DBI group was significantly higher than that in OBI group and NBIT group ( P <0.05). Conclusions: HBV can inhibit the secretion of TLR 9 in parturient to some extent, but HBeAg can stimulate the secretion of TLR 9. However, with the increased severity of intrauterine transmission of HBV, the level of TLR 9 in parturients is increased by intra-group cross-differentiation. Therefore, TLR 9 is not an independent marker for screening and grouping, but it can be used as an reference indicator for the monitoring and management of HBsAg-positive parturients.