A corpus luteum is not a prerequisite for the expression of progesterone induced blocking factor by T-lymphocytes a week after implantation.
OBJECTIVE
To determine if production of the immunomodulatory protein, progesterone induced blocking factor (PIBF), requires merely progesterone or whether other factors made by the corpus luteum are required.


METHODS
The percentage of peripheral lymphocytes expressing PIBF was determined by obtaining a blood sample from women 9-12 days after embryo transfer. The embryos were either fresh ones following hyperstimulation and oocyte retrieval or were frozen-thawed embryos. Preparation for frozen embryo transfer required corpus luteum suppression with exogenous estrogen. The percentage of lymphocytes expressing PIBF was determined by an immunocytochemistry method.


RESULTS
PIBF expression (>1%) was found in 20.5% of COH and 13.3% of frozen embryo transfer cycles. There either was a significant difference or a trend for higher pregnancy rates when PIBF expression was detected.


CONCLUSIONS
These data corroborate previous conclusions that PIBF is detected in a minority of women in the late luteal phase. A corpus luteum is not required for its expression.
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J H
JH
Department of Obstetrics and Gynecology, The University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School at Camden, Cooper Hospital/University Medical Center, Camden, USA.
Szekeres-Bartho
J
J
Nazari
P
P
Katz
Y
Y
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M L
ML
D003338:Corpus Luteum / Q000378:metabolism*; D015925:Cryopreservation; D010064:Embryo Implantation / Q000276:immunology; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011257:Pregnancy Proteins / Q000096:biosynthesis*; D011374:Progesterone / Q000378:metabolism*; D013491:Suppressor Factors, Immunologic; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism*
C110058:PIBF1 protein, human; D011257:Pregnancy Proteins; D013491:Suppressor Factors, Immunologic; D011374:Progesterone