LEUKEMIA INHIBITORY FACTOR (LIF) PRODUCTION BY HUMAN DECIDUA AND ITS RELATIONSHIP WITH PREGNANCY HORMONES

The expression of leukemia inhibitory factor (LIF) by murine uterus wa s shown to be regulated by maternal hormones and was not dependent on the presence of an embryo. The objective of this study was to investig ate whether in humans the secretion of LIF during early pregnancy is u nder maternal control and whether its production is correlated with pr egnancy hormones, progesterone and beta-human chorionic gonadotropin ( beta hCG). To exclude tile possibility of paracrine interaction of dec idua with trophoblast, we examined the secretion of LIF in women with extrauterine pregnancy. The present study was designed as a prospectiv e, blinded, clinical and immunobiochemical study. The endometrial biop sies were performed on 12 women during surgery for ectopic pregnancy. On the same day, the level of progesterone and beta hCG in maternal pl asma was examined. LIF concentration was determined in supernatants ta ken from cultured decidual explants. LIF production by decidual cultur e explants was found in all women with an ectopic pregnancy (Median 50 15 pg, range 1389-19 304 pg). There was no correlation between the LIF production and the term of pregnancy, or with the level of circulated beta hCG (p > 0.05). However, when the concentration of progesterone in circulating plasma was less than 5 ng/ml, the secretion of LIF was 2.3-foId higher as compared to women who had progesterone levels of mo re than 5 ng/ml (p < 0.01). Therefore, we conclude that LIF is activel y produced by human decidua and that the production of this cytokine d oes nor depend on the presence of fetotrophoblast. This study demonstr ates for the first time that progesterone downregulates the secretion of LIF in the decidua during early pregnancy.