Enhanced Serum Levels of sFlt1: Impact on Materno–Fetal CMV Transmission

Background: Antenatal Cytomegalovirus infection (CMV) can be associated with severe fetal symptoms and newborn outcome. The current prenatal diagnosis is based on amniocentesis (AC). No reliable biomarker for fetal infection is available. Methods: We measured Placenta-derived growth factor (PlGF), and soluble fms-like tyrosine kinase 1 (sFlt1), concentrations in maternal serum and amniotic fluid (AF) in context of maternal CMV primary infection. Blood sampling was carried out at the time of AC for detection of fetal CMV infection. The study cohort was divided into four subcohorts according to the presence or absence of fetal infection and preemptive hyperimmunoglobulin (HIG) treatment during the time interval between diagnosis of the CMV primary infection and AC. Results: The study cohort involved 114 pregnancies. In the non-transmitting subcohorts (NT) with and without prior HIG treatment, the median sFlt1 concentrations were 1.5 ng/mL (NT, HIG+) and 1.4 ng/mL (NT, HIG−), respectively. In the two transmitting groups (T) the concentrations were 1.3 ng/mL (T, HIG+) and 2.3 ng/mL (T, HIG−), respectively (NT, HIG− vs. T, HIG−, p < 0.001). The corresponding PlGF levels and the sFlt1/PlGF ratios showed no significant differences between the cohorts. The empirical cut-off values <1504 pg/mL sFlt1 and <307 pg/mL PlGF, were associated with the exclusion of CMV transmission (p < 0.001). Conclusion: sFlt1 concentration in the maternal blood could be a predictive biomarker for maternofetal CMV transmission.