Unbalanced Pro-Inflammatory and Anti-Inflammatory Cytokines Ratio and Endometriosis: A Contributive Pathogenic Role ?

We recently read the original research entitled “Serum and Peritoneal Fluid Cytokine Profiles in Infertile Women with Endometriosis” by Tarokh et al. published in your journal. In this paper, the authors evaluated the concentration of interferon (IFN)-γ and other cytokines within serum and peritoneal fluid (PF) of infertile patients affected by endometriosis (1). Notably, they found a significantly reduced serum IFN- (p=0.001) and increased transforming growth factor (TGF)-β1 (p=0.030), in PF of 30 patients, compared with the 30 healthy women. Moreover, the ratio between pro-inflammatory and anti-inflammatory cytokines (specifically, interleukin (IL)-17 and IL-23 in serum samples, tumor necrosis factor (TNF)-α and IL-10, IL-17 and IL-10 ratios in PF samples) increased the values in patients with endometriosis. The rationale of this study is the aberrant activity of inflammatory pathways (among which, NF-kB) in the development and establishment of this benign chronic disease. It is a known fact that there is a strong relationship between estrogen production (which occurs within endometriotic nodules due to aberrant aromatase expression and activity (2)) and pro-inflammatory cytokines production (3). Moreover, current first-line approaches to treating symptoms (in primis dysmenorrhea) further consist of the administration of anti-inflammatory non-steroidal drugs (NSAIDs), aiming to reduce the prostaglandin production by inhibiting cyclooxygenase enzymes (4). Overall, a methodological concern of this study was that the authors did not precisely report, in the “materials and methods” section, which phenotype of endometriosis the patients had; in fact, it is likely that ovarian endometriosis, deep endometriosis and superficial (peritoneal) endometriosis have different pathogenesis, along with distinguished histological and molecular characteristics (5,6). For this reason, Tarokh et al. should report whether or not only patients with a specific phenotype of endometriosis or a combination of them were considered eligible.