Secretion of human leukocyte antigen-G by human embryos is associated with a higher in vitro fertilization pregnancy rate.

OBJECTIVE: To investigate whether secretion of soluble human leukocyte antigen-G (HLA-G) by human embryos is associated with embryo development and IVF pregnancy outcome.
DESIGN: Retrospective study.
SETTING: In vitro fertilization program affiliated with a university research center. PATIENT(S): Infertile couples attending an IVF program were selected. INTERVENTION(S): Embryo culture conditioned medium (72 hours) from cases in which intracytoplasmic sperm injection was used for fertilization. MAIN OUTCOME MEASURE(S): Soluble HLA-G in embryo culture medium samples from IVF patients was assayed and associations between soluble HLA-G secretion and outcome measures were analyzed. RESULT(S): Two hundred seventy of 386 samples had detectable soluble HLA-G. Soluble HLA-G secretion was independent of embryo grade or patients' age. The cleavage rate of embryos secreting soluble HLA-G was significantly higher than that of those lacking it (blastomere number 6.71 +/- 0.09 vs. 5.86 +/- 0.22). The live birth rate from embryos with soluble HLA-G was significantly higher than that of those without (48.4% vs. 17.1%, chi(2) = 9.09). Combining soluble HLA-G detection and cleavage rate was most predictive of pregnancy. CONCLUSION(S): Our five conclusions are as follows: [1] embryonic secretion of soluble HLA-G protein is variable, [2] secretion of HLA-G is correlated with a higher cleavage rate, [3] secretion of HLA-G is associated with a higher pregnancy rate, [4] HLA-G secretion is a better independent predictor than cleavage rate alone, and [5] the combination of soluble HLA-G detection and high cleavage rate was the best predictor of outcome.