title: Use of lymphocyte platelet binding assay for detecting a preimplantation factor: a quantitative assay.
abstract: OBJECTIVE
  To evaluate the ability of the lymphocyte/platelet binding assay to identify a preimplantation factor (PIF).
  
  
  METHODS
  Percentages of binding of lymphocytes by platelets in the presence of sera from 30 known pregnant and 30 nonpregnant individuals were compared using a novel lymphocyte/platelet binding assay. The assay is performed using a combination of a heat inactivated sera with donor O+lymphocytes, activated complement and an antibody against CD2 (T11, Ortho Pharmaceuticals).
  
  
  RESULTS
  In nonpregnant females (23.6 +/- 6.5%) and males (17.7 +/- 4.7%) the percentage of lymphocytes bound by platelets was significantly different from pregnant women (56.1 +/- 15.9%) (P < 0.0001). Serial sampling of blood in five women undergoing IVF/ET who had normal pregnancies showed the detection of PIF by 4 days after transfer. The lymphocyte/platelet binding assay was not influenced by hCG, progesterone and estradiol. The interassay and intrassay variabilities were < 3%.
  
  
  CONCLUSIONS
  The lymphocyte/platelet binding assay is a simple, reproducible, specific and cost efficient assay for measurement of PIF. Application of this assay will provide investigative and diagnostic tools for identifying and monitoring early pregnancy events.
authors.affiliation: Reproductive Immunology, Genetics & IVF Institute, Fairfax, VA 22031.
authors.forename: E R
authors.initials: ER
authors.lastname: Barnea
authors.forename: K I
authors.initials: KI
authors.lastname: Lahijani
authors.forename: R
authors.initials: R
authors.lastname: Roussev
authors.forename: J D
authors.initials: JD
authors.lastname: Barnea
authors.forename: C B
authors.initials: CB
authors.lastname: Coulam
mesh_terms: D001681:Biological Assay / Q000379:methods; D001685:Biological Factors / Q000097:blood* / Q000502:physiology; D001792:Blood Platelets / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology; D006063:Chorionic Gonadotropin / Q000502:physiology; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood* / Q000502:physiology
chemical_list: D001685:Biological Factors; D006063:Chorionic Gonadotropin; D011257:Pregnancy Proteins; C000605122:preimplantation factor, human