The human ovarian follicular fluid level of interleukin-8 is associated with follicular size and patient age.

OBJECTIVE To investigate the relationship between interleukin-8 (IL-8) in the human ovarian follicle and follicular size, patient age, and fertility factors in IVF cycles. DESIGN Prospective study. SETTING University hospital research laboratory and infertility clinic. PATIENT(S) Women undergoing IVF with oocyte retrieval. INTERVENTION(S) Follicular fluid (FF) aspiration, oocyte isolation, FF storage, and experimental studies. MAIN OUTCOME MEASURE(S) Quantization of IL-8 by ELISAs and protein microarray; high-performance liquid chromatography (HPLC) followed by ELISA and Western blotting to evaluate alpha(2)-macroglobulin (alpha(2)M) bound IL-8; association of IL -8 to follicular size, patient age, and IVF outcomes. RESULT(S) Samples of FF from 63 patients contained an average of 629.59 pg/mL of IL-8 with 50%-70% bound to alpha(2)M. Large follicles contained higher levels of IL-8 than small follicles (937.34 vs. 86.97 pg/mL). The IL-8 concentration in the large follicles of women of young age was higher than that of older reproductive age women (1,373.61 vs. 673.29 pg/mL). There were no statistically significant associations found between IL-8 concentration and other IVF cycle factors or pregnancy outcome. CONCLUSION(S) Our findings indicate that IL-8 is present in FF, both in its free and alpha(2)M-bound state, and its concentration is correlated with follicular size and patient age.