Evaluation Of HBV Markers In Cells And Tissues Of Pregnant Women With HBV Infection And Their Fetuses

Intrauterine infection of hepatitis B virus (HBV) is the main cause of hepatitis B carriers and patients with chronic hepatitis B in China, and is the most highly risk factor of liver cirrhosis and hepatocellular carcinoma (HCC). By far, there is no precise definition of intrauterine infection of HBV. HBV markers detected in serum of neonates at birth may be due to intrauterine infection or intrauterine transmission. Precisely defined, intrauterine transmission refers to the course of the virus transmission from mothers to fetuses, while intrauterine infection refers to its result that the transmitted viruses finally get into fetal hepatocytes and replicate in them. Intrauterine infection may occur but does not necessarily as the result of intrauterine transmission. It is widely accepted that intrauterine transmission of HBV is a kind of transplacental transmission, mechanisms of which remain unclear. Transplacental leakage was firstly thought to be responsible for the transplacental transmission, defined as "hemagenous route"; later cellular transfer mechanism was put forward, defined as "cellular route". Lately some researchers thought that tranplacental transmission of HBV might occur by route of peripheral blood mononuclear cells (PBMC), referred as "PBMC route". Among studies of intrauterine infection of HBV exists some problems: firstly, there is no precise definition of intrauterine infection of HBV and it is often confused with intrauterine transmission; secondly, it has been confirmed that the infectivity of HBV carrying mothers is related with their virus loads in blood, but on study reviewed the quantitative relation between risk of intrauterine infection and virus load in maternal blood; thirdly, PBMC can not pass placental barrier, their role in intrauterine infection remains unclear. This study is to investigate the relationship between intrauterine transmission and intrauterine infection of HBV, quantitative relation between risk of intrauterine infection and virus load in maternal blood and the possible role of PBMC in intrauterine transmission by testing HBV markers in maternal and fetal cells and tissues. 21 pregnant women positive for HBsAg, HBeAg/anti-HBe, anti-HBc from two hospitals in Chongqing were enrolled in this study, at ages between 20 to 28 and pregnant stages between 18 to 29 weeks. Peripheral blood and Umbilical blood samples were collected from these mothers and their aborted fetuses, and serum and PBMC wereseparated and kept at－80℃. Fetal placenta and liver tissues were snap frozen and kept in fluid nitrogen.Electrochemiluminescence immunoassay (ECLIA) and Elecsys2010 immunoassay system from Roche Company were employed to test the serum samples for HBsAg, anti-HBs, HBeAg, anti-HBe, anti-HBc. It came out that all maternal blood samples were either positive for HBsAg, HBeAg, anti-HBc (15 cases) or positive for HBsAg, anti-HBe, anti-HBc (6 cases); 14 cases were positive in fetal blood, in which 9 were positive for HBsAg, HBeAg, anti-HBc, 2 were positive for anit-HBsAg, HBeAg, anti-HBc, 1 was positive for HBsAg and anti-HBc, and the last two were positive for HBsAg and anit-HBc respectively.DNA templates were prepared from the above serum samples and a fixed amount of PBMC, then HBV DNA was detected by polymerase chain reaction (PCR), and HBV DNA copies per PBMC were calculated from PCR assay results. DNA templates were prepared from about 2g frozen liver and placenta tissues and DNA OD was tested before tested by PCR, then HBV DNA copies per μg DNA were calculated from PCR assay results. It came out that for 21 cases being tested for HBV DNA by PCR assay, all were positive in maternal blood; 11 were positive in maternal PBMC; 14 were positive in placental tissues; 9 were positive in fetal blood; 5 were positive in fetal liver tissues; though none was positive in fetal PBMC. In three of the five cases positive in fetal liver tissues, maternal PBMC were negative. In all cases positive in fetal liver tissues, umbilical blood samples were positive; In all cases posi...