title: [Identification of the origin of single nucleated red blood cells and free DNA in peripheral blood of pregnant women].
abstract: OBJECTIVE
  To investigate the feasibility of using single fetal nucleated red blood cells (FNRBCs) and free DNA for noninvasive prenatal diagnosis.
  
  
  METHODS
  116 samples of maternal blood were analyzed. Single FNRBCs were isolated from the peripheral blood samples of 51 pregnant women with the gestational period of 14 to 26 weeks by micromanipulation techniques after density gradient centrifugation. Nested polymerase chain reaction method was used to amplify the SRY gene. Plasma DNA in blood samples of 65 pregnant women with the gestational period of 5 approximately 40 weeks were extracted and primer extension preamplification (PEP) and nested polymerase chain reaction were employed to amplify the SRY gene. Chorionic tissue/amniotic cells were extracted to compare the concordance between the examination result of the meternal blood and that of chorionic tissue/amniotic cells. Venous blood of healthy men and unpregnant women were used as controls.
  
  
  RESULTS
  (1) The detection rate of single nucleated red blood cells was 90.20% (46/51). (2) The concordance rate of SRY gene amplification results of single cells with real fetal sex was 82.61% (38/46), the sensitivity rate was 80.00% (24/30), and the specificity rate was 87.50% (14/16). (3) The concordance rate of SRY gene amplification results of free DNA with real fetal sex was 90.77% (59/65), the sensitivity rate was 89.13% (41/46), and the specificity rate was 94.74% (18/19).
  
  
  CONCLUSIONS
  (1) The single nucleated red blood cells and free DNA in maternal blood are of fetal origin and can be one of the valuable material sources for prenatal diagnosis. (2) The detection purity of FNRBC by using micromanipulation techniques is nearly 100% and it provides a new way for noninvasive prenatal diagnosis.
authors.affiliation: Department of Gynecology and Obstetrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 China.
authors.forename: Hanping
authors.initials: H
authors.lastname: Chen
authors.forename: Taoran
authors.initials: T
authors.lastname: Wang
authors.forename: Guifang
authors.initials: G
authors.lastname: He
authors.forename: Yunping
authors.initials: Y
authors.lastname: Lu
authors.forename: Tingyuan
authors.initials: T
authors.lastname: Ma
mesh_terms: D000328:Adult; D004247:DNA / Q000097:blood*; D004900:Erythroblasts / Q000502:physiology*; D005260:Female; D005333:Fetus / Q000502:physiology; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism* / Q000502:physiology; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012743:Sex Preselection
chemical_list: D004247:DNA