Ovarian endometrioma but not deep infiltrating endometriosis is associated with increased serum levels of interleukin-8 and interleukin-6

Cytokines, and specifically interleukin 6 (IL-6) and interleukin 8 (IL-8), have been associated with the pathogenesis of endometriosis. We studied serum concentrations of IL-6 and IL-8 in patients with deep infiltrating endometriosis (DIE) or ovarian endometriomas (OE), but no other forms of associated endometriosis disease type. We carried out a case–control study including 19 patients with OE alone (OE group), 14 patients with DIE alone (DIE group) and 24 healthy patients without endometriosis (C group). Serum concentrations of IL-6 and IL-8 were measured in the three groups of patients. Serum levels of both IL-6 and IL-8 were significantly higher in the OE group. A high positive correlation was found between serum IL-6 and IL-8 levels in the OE group but not in the DIE and C groups. Serum IL-8 alone achieved the highest predictive value of the presence of OE (adjusted OR: 1.44; sensitivity: 78.2%; specificity: 76.2%). The combination of IL-6 and IL-8 levels did not significantly improve the discrimination between subjects with OE and those with DIE over that of IL-8. OE but not DIE are associated with increased serum levels of IL-6 and IL-8, and thus these may become useful tools for discriminating OE alone from DIE.