Increased levels of interleukin-10 and transforming growth factor-β in the plasma and ascitic fluid of patients with advanced ovarian cancer

Abstract

Objectives To assess expression of the immunosuppressive cytokines IL-10 and TGF-β in the ascitic fluid and plasma of advanced ovarian cancer patients. Setting The Department of Obstetrics and Gynaecology at the University of Arkansas for Medical Sciences. Population Twenty-eight women diagnosed with advanced ovarian cancer and ten normal female controls. Methods Plasma and ascitic samples were collected at the time of surgery and analysed for the presence of IL-10 and TGF-β using a sensitive enzyme-linked immunosorbent assay. Results Elevated levels of IL-10 were detected in the plasma [mean (SD) = 12 (5) pg/mL; range 8 to 23 pg/mL] and in the peritoneal fluid [mean (SD) = 165 (137) pg/mL; range 50 to 556 pg/mL] of ovarian cancer patients, while no detectable IL-10 was found in any of the normal control plasma samples tested. Similarly, plasma levels of TGF-β in ovarian cancer patients were significantly higher [mean (SD) = 1506 (246) pg/mL; range 1020 to 2070 pg/mL] compared with controls [mean (SD) = 937 (187) pg/mL; range 770 to 1140 pg/mL]( P < 0.001). Surprisingly, however, although elevated TGF-β levels were also detected in the peritoneal fluid of all ovarian cancer patients [mean (SD) = 407 (158) pg/mL; range 140 to 770 pg/mL], these levels were significantly lower than those seen in matched plasma samples ( P < 0.001). Conclusions Local and systemic secretion of immunosuppressive cytokines may play an important role in the impaired anti-tumour immune function commonly observed in advanced ovarian cancer. However, the observation that plasma levels of TGF-β are significantly higher than those detected in the ascitic fluid raises the possibility that cells other than tumour cells are responsible for TGF-β release in the bloodstream of these patients.