title: HLA-G expression in trophoblast cells circulating in maternal peripheral blood during early pregnancy.
abstract: OBJECTIVE
  The aim of this study was to assess the use of circulating trophoblast cells in maternal peripheral blood for noninvasive prenatal diagnosis of numeric chromosomal aberrations.
  
  
  METHODS
  A combined procedure for immunocytochemical identification and deoxyribonucleic acid fluorescence in situ hybridization was used after a single enrichment step consisting of density gradient centrifugation. A specific HLA-G monoclonal antibody was used in combination with X and Y chromosome specific probes in deoxyribonucleic acid fluorescence in situ hybridization to confirm fetal identity of cells bearing HLA-G in the case of a male fetus.
  
  
  RESULTS
  We detected fetal trophoblast cells expressing HLA-G in maternal blood starting at 9 weeks' gestation. In addition to fetal sex prediction with X and Y chromosome-specific probes, fetal aneuploidy was confirmed in peripheral blood from a pregnancy complicated by trisomy 21.
  
  
  CONCLUSIONS
  Although the numbers of fetal cells were extremely low, the proof of concept was demonstrated. Early noninvasive prenatal screening for numeric chromosomal abnormalities with fetal trophoblast cells is feasible.
authors: Molecular Biology Laboratory, Department of Clinical Chemistry, University Hospital Vrije Universiteit, Amsterdam, The Netherlands.
authors: I J
authors: IJ
authors: van Wijk
authors: S
authors: S
authors: Griffioen
authors: M L
authors: ML
authors: Tjoa
authors: M A
authors: MA
authors: Mulders
authors: J M
authors: JM
authors: van Vugt
authors: Y W
authors: YW
authors: Loke
authors: C B
authors: CB
authors: Oudejans
mesh_terms: D000911:Antibodies, Monoclonal; D002499:Centrifugation, Density Gradient; D002869:Chromosome Aberrations; D005260:Female; D006680:HLA Antigens / Q000096:biosynthesis* / Q000097:blood; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis* / Q000097:blood; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D017404:In Situ Hybridization, Fluorescence; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000276:immunology*; D011296:Prenatal Diagnosis / Q000379:methods; D012732:Sex Determination Analysis; D014327:Trophoblasts / Q000166:cytology / Q000276:immunology* / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D006680:HLA Antigens; D059951:HLA-G Antigens; D015395:Histocompatibility Antigens Class I