title: Neutrophil extracellular traps in acute chorioamnionitis: A mechanism of host defense.
abstract: OBJECTIVE
  Neutrophil extracellular traps (NETs) were recently described as a mechanism for microbial killing in the amniotic cavity of women with intra-amniotic infection. Such a clinical condition can result in acute chorioamnionitis, a placental lesion characterized by the infiltration of maternal neutrophils in the chorioamniotic membranes. Herein, we investigated whether these infiltrating neutrophils form NETs in the chorioamniotic membranes from women who underwent spontaneous term or preterm labor with acute chorioamnionitis.
  
  
  METHODS
  Chorioamniotic membrane samples were collected from women who underwent spontaneous term or preterm labor with acute chorioamnionitis (n=10 each). Controls included chorioamniotic membrane samples from women who delivered at term or preterm with or without labor in the absence of acute chorioamnionitis (n=10 each). NETs were visualized and semiquantified in the chorioamniotic membranes by using antibodies against neutrophil elastase and histone H3 in combination with DAPI staining.
  
  
  RESULTS
  Neutrophil extracellular traps were abundant in the chorioamniotic membranes from women who underwent spontaneous term or preterm labor with acute chorioamnionitis. NETs were rarely found, or not visualized at all, in the chorioamniotic membranes from women who delivered at term or preterm with or without labor in the absence of acute chorioamnionitis.
  
  
  CONCLUSIONS
  Neutrophil extracellular traps are abundant in the chorioamniotic membranes from women who underwent spontaneous term or preterm labor with acute chorioamnionitis. These findings suggest that chorioamniotic neutrophils can form NETs as a mechanism of host defense against infection or danger signals.
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH/DHHS, Bethesda, MD, and Detroit, MI, USA.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA.|Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Nardhy
authors.initials: N
authors.lastname: Gomez-Lopez
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH/DHHS, Bethesda, MD, and Detroit, MI, USA.|Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, USA.|Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI, USA.|Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH/DHHS, Bethesda, MD, and Detroit, MI, USA.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Yaozhu
authors.initials: Y
authors.lastname: Leng
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH/DHHS, Bethesda, MD, and Detroit, MI, USA.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Valeria
authors.initials: V
authors.lastname: Garcia-Flores
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH/DHHS, Bethesda, MD, and Detroit, MI, USA.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH/DHHS, Bethesda, MD, and Detroit, MI, USA.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA.|Department of Immunology and Microbiology, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Derek
authors.initials: D
authors.lastname: Miller
authors.affiliation: Perinatology Research Branch, Program for Perinatal Research and Obstetrics, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH/DHHS, Bethesda, MD, and Detroit, MI, USA.|Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, USA.
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Hassan
mesh_terms: D000022:Abortion, Spontaneous / Q000276:immunology*; D000208:Acute Disease; D000328:Adult; D000650:Amnion / Q000378:metabolism*; D002465:Cell Movement; D002821:Chorioamnionitis / Q000276:immunology*; D065206:Extracellular Traps / Q000378:metabolism*; D005260:Female; D006657:Histones / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007113:Immunity, Innate; D019272:Leukocyte Elastase / Q000276:immunology / Q000378:metabolism; D009504:Neutrophils / Q000276:immunology*; D011247:Pregnancy; D047928:Premature Birth / Q000276:immunology*; D055815:Young Adult
chemical_list: D006657:Histones; D019272:Leukocyte Elastase
keywords: alarmins; amniotic fluid, DNA; elastase; infection; inflammation; parturition; pregnancy; preterm labor