title: Perforin-positive cytotoxic lymphocytes in pregnancy.
abstract: OBJECTIVE
  To investigate whether perforin-positive, cytotoxic lymphocytes are present in the first and second trimester as well as at term during normal gestation.
  
  
  METHODS
  A monoclonal antibody raised against human perforin was used to detect perforin expression in mononuclear cells in first-trimester abortion, second-trimester preterm labor due to cervical incompetence and term placentas obtained after normal delivery. Fresh frozen tissue sections containing first- and second-trimester decidua and placental tissues as well as decidua of maternal and fetal surfaces of term placenta were stained using an immunoperoxidase method.
  
  
  RESULTS
  Occasional perforin-positive lymphocytes were present in stroma of chorionic villi of term placenta, while most were found in decidua and coagulated blood in maternal vessels and intervillous spaces. The majority of these lymphocytes were CD3-, CD2+ and CD56+. Quantitative comparison of decidual perforin-positive lymphocytes demonstrated a relative increase in these lymphocytes in decidua of second-trimester and term placentas.
  
  
  CONCLUSIONS
  The presence of perforin-positive cytotoxic lymphocytes in maternal blood and decidua during gestation suggests their roles in pregnancy.
authors.affiliation: Department of Pathology, Ohio State University Medical Center, Columbus, USA.
authors.forename: A
authors.initials: A
authors.lastname: Hameed
authors.forename: A J
authors.initials: AJ
authors.lastname: Ying
authors.forename: U
authors.initials: U
authors.lastname: Aslam
authors.forename: D M
authors.initials: DM
authors.lastname: Proca
authors.forename: S
authors.initials: S
authors.lastname: Keyhani-Rofagha
authors.forename: L J
authors.initials: LJ
authors.lastname: Copeland
mesh_terms: D000328:Adult; D003656:Decidua / Q000276:immunology; D005260:Female; D006801:Humans; D008562:Membrane Glycoproteins / Q000032:analysis / Q000097:blood / Q000276:immunology*; D054353:Perforin; D010920:Placenta / Q000276:immunology; D052899:Pore Forming Cytotoxic Proteins; D011247:Pregnancy / Q000276:immunology*; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D054353:Perforin