title: Development and validation of an assay for measuring preimplantation factor (PIF) of embryonal origin.
abstract: OBJECTIVE
  Tests to determine presence of embryos prior to implantation are needed.
  
  
  METHODS
  Sera from women after embryo transfer were tested for preimplantation factor (PIF) using the lymphocyte/platelet binding assay. Autorosettes were counted using blood type O+ donor lymphocytes and platelets incubated with blinded serum in the presence of antiCD2 antibody and rabbit complement. Human chorion gonadotropin (hCG) concentrations were determined 7 days later and compared with results of the lymphocyte/platelet assay. Implantation was confirmed by ultrasonographic evidence of presence of an intrauterine gestational sac. The roles of platelet activating factor (PAF) and chaperonin 10 in the observed phenomena were studied experimentally.
  
  
  RESULTS
  Significantly more lymphocyte/platelet rosette formations were observed when sera from women who successfully implanted were compared to sera from women who failed to implant. Neither PAF nor chaparonin added to the tested sera controls influenced the percentage of lymphocyte/platelets rosettes.
  
  
  CONCLUSIONS
  PIF is a likely candidate to be the next frontier of diagnosing the presence of viable preimplantation embryos in vivo.
authors.affiliation: Reproductive Immunology, Genetics and IVF Institute, Fairfax, VA 22031, USA.
authors.forename: R G
authors.initials: RG
authors.lastname: Roussev
authors.forename: C B
authors.initials: CB
authors.lastname: Coulam
authors.forename: E R
authors.initials: ER
authors.lastname: Barnea
mesh_terms: D001685:Biological Factors / Q000032:analysis*; D001792:Blood Platelets / Q000378:metabolism; D002448:Cell Adhesion / Q000276:immunology; D047108:Embryonic Development / Q000276:immunology*; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism; D011247:Pregnancy; D015203:Reproducibility of Results; D012397:Rosette Formation / Q000379:methods* / Q000592:standards
chemical_list: D001685:Biological Factors