Interleukin 15 concentrations in follicular fluid and their effect on oocyte maturation in subfertile women undergoing intracytoplasmic sperm injection

S. Spanou – D. Kalogiannis – E. Zapanti – M. Gazouli – I. A. Sfontouris  – C. Siristatidis – George Mastorakos


Purpose To calculate the concentrations of interleukin 15 (IL-15) in follicular fluid (FF) and evaluate their relation with oocyte maturation, follicle size, and patients’ body mass index (BMI) and age.
Methods Follicular fluid specimens were obtained from 56 subfertile women undergoing intracytoplasmic sperm injection (ICSI) during oocyte retrieval for measurement of IL-15 concentrations with ELISA. Wilcoxon’s test and Pearson’s correlation coefficient were used to correlate FF concentrations of IL-15with follicular size and stage of oocytematuration, along with patients’ BMI and age.
Results IL-15 concentrations in FF of follicles with immature oocytes were significantly greater than those from follicles with mature ones (median 5.333 vs. 3.250 pg/ml, respectively, p < 0.001). There was a significant negative correlation between IL-15 concentrations and follicle size (r = − 0.333, p = 0.003). No significant correlation was observed between IL-15 concentrations and patients’ BMI and age (p > 0.05).
Conclusions IL-15 concentrations in FF are adversely related with the size of the follicles and the maturity of the corresponding retrieved oocytes in a cohort of expected normal responders undergoing intracytoplasmic sperm injection (ICSI). Follicular fluid concentrations of IL-15 should be investigated as a possible predictive factor for oocyte maturity.