O-26: Importance of IL-18 in Serum and Follicle Fluid in The Context of Fertility Treatment

Background: Some authors detected significantly higher IL-18 levels in serum, peritoneal, and pleural fluids of patients with severe OHSS as compared with control groups and suggest a role of IL- 18 as a marker of OHSS. Lower levels of IL-18 have been found to characterize unexplained infertility. In this study, we analyzed the importance of IL-18 levels in serum and follicle fluid in response to ovarian stimulation with gonadotropins, in correlation to pregnancy rate and also to clinical parameters. Materials and Methods: From a total sample of 90 patients (2011-2013), we analyzed the level of IL-18 in serum and FF on the day of FP. IL-18 mean and cut-off levels were evaluated in serum and FF on the day of FP by the ELISA method: a. in response to ovarian stimulation with gonadotropins, between patients with a poor and a good response. b. To the resulting pregnancy rate and c. by comparing BMI Results: IL-18 levels in serum were significantly higher than in FF (p<0.001) revealing a positive and significant correlation (r = 0.84, p<0.001). IL-18 levels in serum and in FF of patients with a BMI lower than 21 were significantly lower than in patients with a BMI higher than 22 (p= 0.015). Patients with a good response (E2 ≥ 2500 pg/ml, number of follicles ≥7 on the day of hCG injection) showed significantly higher IL-18 mean levels on the day of FP than patients with a poor response (E2 ≤ 2500 pg/ml, follicles ≤6, p<0.001). We found a cut-off level of 158.6 (ng/ml) in serum with a sensitivity of 61% and a specificity of 64.5%. The pregnancy rates were 39% below and 32% above this cut-off level. Conclusion: Our data suggest that IL-18 exerts an influence on ovarian function and thus on the result in hyperstimulated IVF/ICSI patients. Cut-off level for IL-18 is clinically relevant.