PLACENTAL CYTOPATHIC DAMAGE FACTOR DUE TO PARVOVIRUS B19 – AS A HALLMARK OF INTRAUTERINE SYMPTOMATHY OF INFECTED FETUS

Abstract

Aim of the work. The focus of this study was to analyze the frequency of fetal intrauterine symptomatic realization as a result of B19 parvovirus infection of pregnant women during I and II gestation periods, with the combination of determination the levels of alpha-fetoprotein in maternal serum blood and histopathological investigation of placenta in cases of negative effects for infected fetuses. Materials and methods. A total of 478 pregnant women were at risk of infection and screened for parvovirus B19. The study was based on serological, morphological and virological testing of fetuses from mothers with confirmed parvovirus B19 infection. Infection of pregnant women was detected by serological diagnosis of specific antibodies IgM and IgG to parvovirus B19. Intrauterine fetal infection was confirmed by polymerase chain reaction method. Levels of alpha-fetoprotein in meternal venous blood were detected using an immunochemical test method. An antenatal diagnosis of hydrops fetalis was confirmed by ultrasound scanning. Placenta from the 8 infected fetuses was studied histologically with hematoxylin and eosin staining using electron microscope during gestational periods of 12-22 weeks. Statistical analysis of the obtained data was carried out using nonparametric statistics with the definition of Fisher's criterion. Results and discussion. The average gestational period of symptomatic manifestations of intrauterine fetal infection was 19.9±0.5 weeks of gestation. It was established that in 33 of cases were confirmed the intrauterine infection due to parvovirus B19 by using the morphological placenta tissue analysis. The research found that the levels of maternal serum alpha-fetoprotein was significantly higher (in 2.17 times) in group of fetuses who suffered from fetal hydrops and in cases of intrauterine fetal death before detecting the general echographic sings of fetal failure (p˂0.05). It will be very important to compare this indicator with the Doppler ultrasound measurements of the human fetal middle cerebral artery peak systolic velocity (MCA PSV) and blood flow parameters in the fetal ductus venosus and to predict the possibility of poor perinatal outcomes. It was identified a cytopathic effect in placental cells viral origin and detected in cells of the cytotrophoblast, syncytiotrophoblast, endothelial cells, and blood cells. Conclusions. Parvovirus B19 fractions were visualized in 100 % of cases of miscarriages with fetal hydrops and placental edema during 12-22 weeks of gestation, while acute maternal parvovirus infection (with the detection of IgM against to parvovirus B19) was diagnosed by immunoassay only in 62.5 % of cases. Detection of B19 particles in placental tissue from fetuses with non-immune origin hydrops is an auxiliary method in the diagnosis of vertical transmission of parvovirus during pregnancy. It is more preferable to estimate the levels of alpha-fetoprotein in maternal serum blood in case of parvovirus B19 affected pregnancies as raising rates of this marker may be an early prediction hallmark for adverse fetal outcome.