title: Evidence that exposure to progesterone alone is a sufficient stimulus to cause a precipitous rise in the immunomodulatory protein the progesterone induced blocking factor (PIBF).
abstract: OBJECTIVE
  To determine if exposure to progesterone alone is sufficient to increase the production of the immunomodulatory protein known as the progesterone induced blocking factor (PIBF). Also to determine what method of progesterone delivery or form of P best stimulates PIBF secretion.
  
  
  METHODS
  Serum samples from patients with infertility and paid volunteers were evaluated for both PIBF and progesterone at various times during the follicular phase and the luteal phase in both natural cycles and cycles involving embryo transfer after endogenous and exogenous progesterone exposure and after various synthetic progestins. PIBF was measured by a non-commercial research ELISA assay. Comparisons were made of serum PIBF before and after exposure to progesterone, 17-hydroxyprogesterone, and oral contraceptives. PIBF was also measured before and after transfer of embryos.
  
  
  RESULTS
  Progesterone alone without exposure to the fetal allogeneic stimulus was able to produce a marked increase in serum PIBF. Neither a synthetic progestin (19-nortestosterone derivative) nor 17-hydroxyprogesterone caused an increase in PIBF. Some PIBF is generally detected even in the follicular phase.
  
  
  CONCLUSIONS
  A previous concept considered that an allogeneic stimulus, e.g., from the fetal semi-allograft, was necessary to induce de novo progesterone receptors in gamma delta T cells, which, in turn, when exposed to a high concentration of progesterone, would secrete high levels of PIBF. These data show that exposure to an allogeneic stimulus is not needed to cause a marked rise in PIBF, merely progesterone alone is sufficient.
authors.affiliation: Department of Obstetrics and Gynecology, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, USA.
authors.forename: Rachael A
authors.initials: RA
authors.lastname: Cohen
authors.affiliation: Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Cooper Medical School of Rowan University, Camden, NJ, USA. laurie@ccivf.com.|, 7447 Old York Road, Melrose Park, PA, 19027, USA. laurie@ccivf.com.
authors.forename: Jerome H
authors.initials: JH
authors.lastname: Check
authors.affiliation: Department of Obstetrics, Gynecology and Reproductive Sciences, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Dougherty
mesh_terms: D019326:17-alpha-Hydroxyprogesterone / Q000008:administration & dosage; D000328:Adult; D064591:Allografts; D003276:Contraceptives, Oral / Q000008:administration & dosage; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D056747:Immunomodulation / Q000187:drug effects; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood*; D011374:Progesterone / Q000008:administration & dosage / Q000097:blood*; D013491:Suppressor Factors, Immunologic / Q000097:blood*; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism
chemical_list: D003276:Contraceptives, Oral; C110058:PIBF1 protein, human; D011257:Pregnancy Proteins; D013491:Suppressor Factors, Immunologic; D011374:Progesterone; D019326:17-alpha-Hydroxyprogesterone
keywords: Fetal semi-allograft; Immunomodulatory protein; Natural killer cells; Progesterone; Progesterone induced blocking factor