Elevated interleukin-10 and sex steroid levels in peritoneal fluid of patients with ovarian hyperstimulation syndrome.

BACKGROUND: The ovarian hyperstimulation syndrome (OHSS) following ovulation induction is characterized by a cystic enlargement of the ovaries with an acute third space fluid sequestration. Inflammatory cytokines mediate the inflammatory response (IL-1, IL-2, IL-6, IL-8, TNFalpha) and play a crucial role in the pathogenesis of OHSS. OBJECTIVE: To determine the role of the anti-inflammatory cytokine interleukin-10 (IL-10) in OHSS and to examine its correlation with 17beta-estradiol and progesterone. STUDY DESIGN: Peritoneal fluid and serum samples were collected from 9 patients with severe OHSS after ovulation induction by administration of GnRH-analogues followed by hMG (n=5) or recombinant FSH (n=4). Patients (n=19) without pathological findings at laparoscopy served as non-pregnant controls and pregnant women (n=14) between 7 and 16 weeks of gestation served as positive controls. Samples were assayed for IL-10 by commercially available ELISA and for for 17beta-estradiol and progesterone by RIA. Statistical analysis was performed by non-parametric Mann-Whitney U-test and results are presented as the median and range. RESULTS: OHSS patients had significantly higher peritoneal fluid IL-10, 17beta-estradiol and progesterone levels than patients during early pregnancy and than the control group. No correlation was found between peritoneal fluid or serum IL-10 and 17beta-estradiol or progesterone in the different groups. Serum 17beta-estradiol and progesterone, but not serum IL-10 levels were elevated in OHSS and during early pregnancy. CONCLUSIONS: High concentrations of IL-10 in peritoneal fluid suggest a role of this anti-inflammatory cytokine during OHSS. 17beta-estradiol and progesterone were elevated in peritoneal fluid and serum during OHSS but no correlation with IL-10 concentrations was found. Therefore, we assume that IL-10 has a role in OHSS as a local mediator of inflammation, however, it presents different aspects of the OHSS than the sex steroids 17beta-estradiol and progesterone.