Serum and cyst fluid levels of interleukin (IL) -6, IL-8 and tumour necrosis factor-alpha in women with endometriomas and benign and malignant cystic ovarian tumours

BACKGROUND: Altered expression of cytokines has been suggested as a specific event for the maintenance and progression of endometriomas. Few data exist on cytokine expression in endometriomas compared with benign and malignant ovarian tumours. Hence, serum and cyst fluid levels of interleukin (IL)-6, IL-8 and tumour necrosis factor-alpha (TNF-alpha) were evaluated in women with endometriomas and compared with those in women with benign or malignant ovarian tumours. METHODS: Investigations included immunoradiometric determination of serum and cyst fluid concentrations of IL-6, IL-8 and TNF-alpha in 34 women with endometriomas, 30 women with benign and 13 women with malignant cystic ovarian tumours. RESULTS: Serum IL-6 levels were higher in ovarian cancer than in endometriomas (P<0.01) or benign tumours (P<0.01). Serum TNF-alpha levels differed between benign tumours and endometriomas (P<0.01), but not between endometriomas and malignant tumours. Cyst fluid levels of IL-8 were higher in endometriomas than in benign tumours (P<0.001) and lower than in malignant tumours (P=0.03). Cyst fluid levels of TNF-alpha differed between malignant tumours and endometriomas (P<0.01) and benign tumours (P<0.01), but not between endometriomas and benign tumours. In the endometriomas group, a positive correlation was found between serum and cyst fluid levels of IL-6 (P=0.003, rho=0.633), and between serum levels of IL-6 and IL-8 (P=0.03, rho=0.415). CONCLUSIONS: Endometriomas were associated with serum TNF-alpha levels similar to those found in women with ovarian cancer, while serum IL-6 levels and cyst fluid IL-8 levels were intermediate between those observed in benign and malignant ovarian tumours.