IL-18 and IL-18 binding protein concentration in ovarian follicular fluid of women with unexplained infertility to PCOS during in vitro fertilization

The correlation between the concentration of interleukin (IL) 18 in follicular fluid and the pathogenesis of Polycystic Ovary Syndrome (PCOS) is unclear. Therefore, we tested the IL-18 and IL-18 binding protein (IL-18BP) levels in follicular fluid (FF) and serum in PCOS women undergoing reproductive measures and to explore their possibly correlation with PCOS. Serum and pooled follicular fluid levels of IL-18, IL-18BP and IL-18/IL-18BP ratios were evaluated in sixty patients with PCOS and sixty women with unexplained infertility undergoing in vitro fertilization. The FF IL-18 levels were increased in PCOS group than the CON group (p < 0.01), and the IL-18 levels were significantly higher in the FF than in serum in PCOS group. Furthermore, the elevated FF IL-18 levels have no correlation with the serum IL-18 levels. Additionally, the expression of IL-18 in the follicular fluid of the overweight PCOS patients was increased compared to the normal weight PCOS patients, while in the overweight patients, FF IL-18 was significantly higher in the PCOS group than in the control group. The FF IL-18 and IL-18BP may have a local involvement in the pathogenesis of PCOS. The PCOS itself and overweight will aggravate the local inflammatory response in the ovary. Further studies are needed to elucidate this issue.