title: Evidence for a leukocyte adhesion factor produced by the early embryo.
abstract: OBJECTIVE
  To determine if the embryo may induce adhesive molecules needed for implantation.
  
  
  METHODS
  Determination of whether platelet rosetting around lymphocytes might occur when exposed to sera from pregnant, but not nonpregnant patients and from culture fluid from embryos but not oocytes.
  
  
  RESULTS
  90.2% of women with positive sera beta human chorionic gonadotropin (beta-hCG) levels taken at least 12 days postovulation demonstrated platelet rosette factor (PRF) vs only 18.7% when beta-hCG was negative. Using mid-luteal phase sera in women receiving hCG injection 1 wk before, 64.7% had positive PRF when serial beta-hCG levels were positive as did 100% of samples taken from in vitro fertilization (IVF) patients; however, only 15.3% were positive with negative serial hCG levels. Culture media from fertilized oocytes and embryos tested positive for PRF, but follicular fluid and media from unfertilized oocytes were negative.
  
  
  CONCLUSIONS
  The early embryo secretes a factor(s) that gains access to maternal serum and promotes increased lymphocyte/platelet adhesiveness.
authors.affiliation: Department of Obstetrics and Gynecology, University of Medicine and Dentistry of New Jersey, Camden, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Check
authors.forename: A
authors.initials: A
authors.lastname: Bollendorf
authors.forename: H A
authors.initials: HA
authors.lastname: Askari
mesh_terms: D001792:Blood Platelets / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000097:blood; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D046508:Culture Techniques; D016207:Cytokines / Q000096:biosynthesis / Q000097:blood / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000378:metabolism*; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000276:immunology*; D011247:Pregnancy; D012397:Rosette Formation
chemical_list: D015815:Cell Adhesion Molecules; D018997:Chorionic Gonadotropin, beta Subunit, Human; D016207:Cytokines