Elevated interleukin-6 levels in peritoneal fluid of patients with pelvic pathology

To determine if interleukin 6 (IL-6) is a normal constituent of peritoneal fluid (PF), and if various types of pelvic pathology influence its presence within the PF microenvironment.

Peritoneal fluid from 73 women obtained at the time of laparoscopy was examined for the presence of IL-6 using an IL-6 specific sandwich enzyme-linked immunosorbent assay. Thirty-nine patients had pelvic endometriosis, 17 had nonendometriotic pelvic adhesive disease, and 17 subjects undergoing tubal sterilization without evidence of pelvic pathology served as controls.

Immunoreactive IL-6 was observed in the PF of all 73 subjects (range 0.26 to 11.16 ng/mL). The mean concentration of IL-6 was higher in women with nonendometriotic pelvic adhesions as compared with control subjects (1.28 +/- 0.16 versus 0.80 +/- 0.06 ng/mL, P less than 0.03). There was no difference in the mean peritoneal concentrations of IL-6 between women with endometriosis (1.16 +/- 0.28 ng/mL) and controls, P = 0.38. Twenty-seven of 73 patients (37%) demonstrated elevated levels (greater than 1.0 ng/mL) of IL-6. Patients with pelvic adhesions were significantly more likely to have elevated concentrations of IL-6 than controls (10/17 [59%] versus 3/17 [18%], P less than 0.02). Alternatively, the percentage of patients with elevated IL-6 concentrations did not differ between patients with endometriosis or controls (14/39 [36%] versus 3/17 [18%], P greater than 0.10).

These findings demonstrate that IL-6 is a normal constituent of PF and that elevated levels are found in many patients with pelvic adhesions.