HLA-G LEVELS IN FOLLICULAR FLUID ARE NOT ASSOCIATED WITH FOLLICULAR G-CSF CONCENTRATIONS IN WOMEN UNDERGOING IN VITRO FERTILIZATION

Abstract

Recently, soluble human leukocyte antigen-G (sHLA-G) and granulocyte colony-stimulating factor (G-CSF) quantified in the follicular fluid have been proposed as non-invasive biomarkers of oocyte competence in both stimulated and natural IVF/ICSI cycles. sHLA-G, G-CSF and their receptors were described in various human fetal tissues and it was suggested that they play an important role in ovulation, oocyte maturation, embryo development and implantation. However, the possible association between these two molecules in the follicular fluid has not been studied yet. The purpose of the present study was to determine whether the sHLA-G levels are associated with the G-CSF levels in follicular fluid of women undergoing in vitro fertilization. This is a cohort study of 56 women undergoing stimulated cycles and in vitro fertilization between September 2019 and November 2019 at Nadezhda Women’s Health Hospital. Follicular fluid from up to six clear follicular aspirates was collected during regular egg collection procedure of 56 patients. Samples were stored at -20°C until measurement. Follicular fluid levels of sHLA-G and G-CSF were evaluated by ELISA kits (Elabscience; E-EL-H1663 and RayBiotech; ELH-GCSF-1, respectively) according to the manufacturer’s instructions. The absorption was measured on a microplate reader (Beckman Coulter DTX 880 Multimode detector) at 450 nm. Statistical analysis was performed using SPSS v.21 (IBM Corp., Armonk, NY, USA). sHLA-G was detected in all 56 follicular fluid samples, with a median value of 47.52 IU/ml and a range of 13.85-63.06 IU/ml. Follicular fluid G-CSF was also detected in all samples and ranged between 3 and 116 pg/ml with a median of 16.23 pg/ml. Measured sHLA-G levels did not show a significant correlation with G-CSF concentration in follicular fluid (P = 0.63). This is the first report regarding the association between follicular fluid levels of sHLA-G and G-CSF. Although the increased secretion of both sHLA-G and G-CSF usually correlates with better oocyte quality and implantation success, our findings suggest that they are not related to each other.