title: Placental fas/fas ligand expression in early pregnancy losses.
abstract: OBJECTIVE
  The aim of this study was to compare the expression levels of Fas and Fas ligand (FasL) in first-trimester placentas obtained from spontaneous abortions in patients with antiphospholipid antibody syndrome (APS) or factor V (FV) Leiden mutation, compared with values in placentas from induced abortions in patients negative for these conditions.
  
  
  METHODS
  We studied explants from 6- to 10-week-old placentas that had been prepared by collagenase digestion from 10 spontaneous abortions from APS-positive patients, nine spontaneous abortions in patients positive for FV Leiden mutation, and 10 induced abortions. All tissues were analyzed by flow cytometry for expression of Fas and FasL.
  
  
  RESULTS
  Flow cytometric analysis showed that placental FasL expression was significantly lower in abnormal pregnancies than in normal ones. However, no such difference was observed for Fas expression.
  
  
  CONCLUSIONS
  FasL on placental cells may be involved in the maintenance of immune privilege, thereby ensuring the safety and growth of placental tissues. Dysregulation of apoptotic mechanisms may play a critical role in spontaneous abortions.
authors.affiliation: Department of Obstetrics and Gynecology, Health Ministry Etlik Women's Health and Maternity Hospital, Ankara, Turkey. emineseda@yahoo.com
authors.forename: Emine Seda
authors.initials: ES
authors.lastname: Guvendag Guven
authors.forename: Hamza
authors.initials: H
authors.lastname: Okur
authors.forename: Mehmet Sinan
authors.initials: MS
authors.lastname: Beksac
mesh_terms: D000022:Abortion, Spontaneous / Q000209:etiology / Q000378:metabolism*; D016736:Antiphospholipid Syndrome / Q000150:complications; D005165:Factor V / Q000378:metabolism; D053222:Fas Ligand Protein / Q000096:biosynthesis*; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D007108:Immune Tolerance / Q000502:physiology; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D019014:fas Receptor / Q000096:biosynthesis*
chemical_list: D053222:Fas Ligand Protein; C095381:factor V Leiden; D019014:fas Receptor; D005165:Factor V