title: Quantitative analysis of intact fetal cells in maternal plasma by real-time PCR.
abstract: OBJECTIVE
  Fetal genetic materials in maternal circulation might be potentially used for non-invasive prenatal diagnosis (NIPD). In this study, we quantitatively analysed the intact fetal cells existing in maternal plasma, which would be a special method of NIPD.
  
  
  METHODS
  Eleven samples from preeclamptic patients, two samples from patients with RhD incompatibilities, and 30 samples from normal pregnancies as controls were collected. The intact cells in the plasma fraction were separated by centrifugation at high speed. The intact cell pellets were washed with PBS to remove any cell-free DNA.
  
  
  RESULTS
  We were able to detect intact fetal cells in 3 out of 11 preeclamptic plasma samples from women carrying male fetuses, and from both plasma samples of RhD incompatibility affected pregnancies. However, intact fetal cells were not detected in all the 16 normal pregnancies with a male fetus, although cell-free fetal DNA was detected in all these cases.
  
  
  CONCLUSIONS
  Intact fetal cells might be present in maternal plasma. However, the rarity of these cells limits their use for reliable, non-invasive prenatal diagnosis. The detection of such cells was successful in some preeclamptic and RhD incompatibility samples, not in the normal controls. Therefore, as opposed to free fetal DNA in maternal blood the use of intact fetal cells does not provide a reliable mode for NIPD.
authors.affiliation: Laboratory for Prenatal Medicine and Experimental Oncology, Department of Obstetrics and Gynecology, University of Basel, Spitalstrasse 21, CH 4031 Basel, Switzerland. xzhong@uhbs.ch
authors.forename: Xiao Yan
authors.initials: XY
authors.lastname: Zhong
authors.forename: Sinuhe
authors.initials: S
authors.lastname: Hahn
authors.forename: Andrea
authors.initials: A
authors.lastname: Steinborn
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Holzgreve
mesh_terms: D002469:Cell Separation; D004247:DNA / Q000097:blood; D005260:Female; D005312:Fetal Blood / Q000166:cytology; D005333:Fetus / Q000166:cytology*; D006801:Humans; D008297:Male; D008431:Maternal-Fetal Exchange; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*
chemical_list: D004247:DNA