title: Elevated Levels of Total Cell-Free DNA in Maternal Serum Samples Arise from the Generation of Neutrophil Extracellular Traps.
abstract: BACKGROUND
  The analysis of cell-free DNA from maternal blood samples has facilitated the noninvasive detection of fetal aneuploidies or hereditary Mendelian disorders. In this context, previous studies have indicated that the pool of cell-free DNA is greater in maternal serum than in plasma samples, necessitating optimized collection and storage protocols. As the source of this increased amount of cell-free DNA is not clear, we have now examined whether neutrophil extracellular traps (NETs) contribute to this material.
  
  
  METHODS
  Serum samples were collected in all three trimesters of normal healthy pregnant women, and at term from cases with manifest preeclampsia. The presence of NET-derived material was demonstrated by the detection of cell-free DNA fragments complexed to neutrophil granular proteins (i.e. myeloperoxidase).
  
  
  RESULTS
  Our data indicate that NET-derived cell-free DNA/myeloperoxidase complexes were greater in serum from normal pregnant women than in normal matching nonpregnant controls. This neutrophil chromosomal material increased incrementally throughout gestation and was most pronounced in cases with preeclampsia.
  
  
  CONCLUSIONS
  By detecting increased levels of cell-free DNA/myeloperoxidase complexes in maternal serum samples, our data indicate that a significant proportion of this material is derived from the generation of NETs.
authors.affiliation: Department of Biomedicine, University Clinics Basel, Basel, Switzerland.
authors.forename: Chanchal
authors.initials: C
authors.lastname: Sur Chowdhury
authors.forename: Sinuhe
authors.initials: S
authors.lastname: Hahn
authors.forename: Paul
authors.initials: P
authors.lastname: Hasler
authors.forename: Irene
authors.initials: I
authors.lastname: Hoesli
authors.forename: Olav
authors.initials: O
authors.lastname: Lapaire
authors.forename: Stavros
authors.initials: S
authors.lastname: Giaglis
mesh_terms: D000328:Adult; D004247:DNA / Q000097:blood*; D065206:Extracellular Traps; D005260:Female; D005865:Gestational Age; D006801:Humans; D009504:Neutrophils; D011225:Pre-Eclampsia / Q000175:diagnosis; D011247:Pregnancy; D044967:Serum / Q000166:cytology; D013997:Time Factors
chemical_list: D004247:DNA