title: Clinical chorioamnionitis at term VII: the amniotic fluid cellular immune response.
abstract: OBJECTIVE
  1) To characterize the cellular composition of the amniotic fluid of patients diagnosed with clinical chorioamnionitis at term, as a function of the presence or absence of microorganisms determined by cultivation techniques, and 2) to characterize the cytokine production by white blood cells present in the amniotic fluid using flow cytometry-based techniques.
  
  
  METHODS
  Amniotic fluid samples from 20 women who had the diagnosis of clinical chorioamnionitis at term were analyzed using cultivation techniques (for aerobic and anaerobic bacteria as well as genital Mycoplasmas). Amniotic fluid IL-6 concentrations were determined by an enzyme-linked immunosorbent assay. Amniotic fluid leukocytes were visualized by using hematoxylin and eosin staining and immunofluorescence. Immunophenotyping of surface markers and cytokines was performed in amniotic fluid leukocytes using flow cytometry.
  
  
  RESULTS
  1) Neutrophils (CD45+CD15+ cells) were the most common leukocyte subset found in the amniotic fluid, followed by monocytes (CD45+CD14+ cells); other white blood cells (such as lymphocytes and natural killer cells) were scarce in the amniotic fluid; 2) the absolute counts of neutrophils and monocytes were significantly higher in patients with microorganisms found in the amniotic fluid than in those without detectable microorganisms, using cultivation techniques; 3) there was a significant correlation between the absolute counts of neutrophils and monocytes determined by flow cytometry (Spearman's correlation=0.97; P<0.001); 4) there was a significant correlation between the absolute white blood cell count determined with a hemocytometer chamber and by flow cytometric analysis (Spearman's correlation=0.88; P<0.001); and 5) the profile of cytokine expression differed between monocytes and neutrophils; while neutrophils predominantly produced TNF-α and MIP-1β, monocytes expressed higher levels of IL-1β and IL-1α.
  
  
  CONCLUSIONS
  Flow cytometry analysis of the amniotic fluid of patients with intra-amniotic infection and clinical chorioamnionitis at term demonstrated that neutrophils and monocytes are the most common cells participating in the inflammatory process. We have characterized, for the first time, the differential cytokine expression by these cells in this important complication of pregnancy.
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Alicia
authors.initials: A
authors.lastname: Martinez-Varea
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Romero
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xu
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Derek
authors.initials: D
authors.lastname: Miller
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Ahmed I
authors.initials: AI
authors.lastname: Ahmed
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Piya
authors.initials: P
authors.lastname: Chaemsaithong
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Noppadol
authors.initials: N
authors.lastname: Chaiyasit
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Lami
authors.initials: L
authors.lastname: Yeo
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Majid
authors.initials: M
authors.lastname: Shaman
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Kia
authors.initials: K
authors.lastname: Lannaman
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Cher
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Sonia S
authors.initials: SS
authors.lastname: Hassan
authors.affiliation: , NICHD/NIH/DHHS, Bethesda, MD, USA.
authors.forename: Nardhy
authors.initials: N
authors.lastname: Gomez-Lopez
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000737:chemistry / Q000166:cytology* / Q000276:immunology; D002821:Chorioamnionitis / Q000276:immunology*; D003430:Cross-Sectional Studies; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007111:Immunity, Cellular; D015850:Interleukin-6 / Q000032:analysis / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism; D011247:Pregnancy; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6
keywords: Cytokine; flow cytometry; interleukin-1 alpha (IL-1α); interleukin-1 beta (IL-1β); interleukin-6 (IL-6); leukocytes; microbial invasion of the amniotic cavity (MIAC); monocytes; neutrophils; parturition