Quantitative abnormalities of fetal trophoblast cells in maternal circulation in preeclampsia

To determine if quantitative abnormalities of circulating fetal trophoblast cells (CFTCs) are associated with preeclampsia.

The trophoblast cell-specific antibody, MEM-G/9 (monoclonal antibody to HLA-G), was applied to distinguish the trophoblast cells from the maternal circulation. The trophoblast cells were isolated by density-gradient centrifugation from maternal blood samples of normal pregnant and preeclamptic women, respectively. After preliminary enrichment, the CFTCs were identified by immunocytochemical staining with the MEM-G/9. To prove fetal origin of the HLA-G-positive cells, primer-extension preamplification (PEP) and polymerase chain reaction (PCR) based on single HLA-G-positive cells were adopted to detect human sex-determining region of the Y-chromosome (SRY) gene.

There were 6.88 +/- 1.54 and 30.56 +/- 5.16 HLA-G-positive cells in 6 mL maternal blood from the normal pregnant (n = 16) and preeclamptic women (n = 18), respectively. The difference was statistically significant (p < 0.001). The SRY gene from the HLA-G-positive cells was detected in all pregnant women carrying male fetuses. The sensitivity and specificity of PEP and PCR for the SRY gene detection were 100%.

It is concluded that enhancement of CFTCs numbers is related to preeclampsia, which provides information useful for noninvasive prenatal diagnosis of preeclampsia.