Soluble Human Leukocyte Antigen G Level in Fluid from Single Dominant Follicle and the Association with Oocyte Competence

PURPOSE: To investigate the direct relationship between the follicular fluid (FF) level of soluble human leukocyte antigen G (HLA-G) and fertilizability of the corresponding oocyte as well as the morphological quality of the corresponding embryo. MATERIALS AND METHODS: Sixty-three patients were stimulated with recombinant FSH combined with gonadotropin-releasing hormone (GnRH) agonist long (n=5) or antagonist protocol (n=58) for standard in vitro fertilization (IVF). At the time oocyte retrieval, follicular fluid was obtained from single dominant follicle in 63 patients, and the level of soluble HLA-G was measured by sandwich enzyme-liked immunosorbent assay (ELISA). Normal fertilization and individual embryo quality were evaluated, and were graded to four categories by morphological criteria (the embryo with symmetrical blastomeres and no fragmentation were assigned as grade A). Good-quality embryo was defined as those with grade A or B. RESULTS: Soluble HLA-G was not detected in 15 FF samples. In the group with positive FF soluble HLA-G (sHLA-G) (n=48), high levels of sHLA-G (>117.758 U/mL) could predict the failure of fertilization with statistical significance {area under the curve (AUC) 0.676, 95% confidence interval (CI) 0.525-0.804}. However, the FF sHLA-G level was not related with the formation of good-quality embryo. CONCLUSION: High level of FF sHLA-G could predict the fertilization failure of the corresponding oocyte, but was not related with the formation of good-quality embryo.