The Concentration of Macrophage-Derived IL-1α and IL-12 in the Peritoneal Fluid of Patients With Endometriosis: A Pilot Case-Control Study

It is supposed that the primary or secondary dysfunction of macrophages may play an essential role in the pathogenesis of endometriosis. It is postulated that macrophage-derived cytokines and signaling molecules, such as IL-1 (interleukin), IL-6, and IL-12, tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), and MCP-1 (monocyte chemoattractant protein) may be involved in the process of endometriosis formation. This pilot study included 47 patients who underwent diagnostic-therapeutic laparoscopy at the II Department of Gynecology, Medical University of Lublin, Poland. Peritoneal fluid was obtained from patients in both the reference and study groups. The number and viability of the cells were assessed. The cells were labeled with monoclonal antibodies and assessed using flow cytometry. Interleukins of macrophage origin in the peritoneal fluid were determined using the enzyme-linked immunosorbent assay (ELISA) test. The peritoneal fluid showed fundamental changes in the concentration of the studied cytokines. We recorded the peritoneal fluid volume for each patient (median ∼5 mL in the endometriosis group vs. ∼4 mL in the reference group) and noted that a larger volume could dilute cytokine levels; cytokine concentrations were thus interpreted per mL of fluid. More than twice as high median IL-12 levels were detected in women in the reference group than in the study group. High levels of IL-1α and low levels of IL-12 in the study group compared to the reference group suggest an immunological component in the etiopathogenesis of endometriosis, although this pilot, exploratory study (n = 47) cannot establish this relationship definitively. All endometriosis cases were laparoscopically confirmed, but histopathological confirmation was obtained in only 20 of 28 cases (71.4%); the remaining 8 patients had superficial Stage I lesions that were not biopsied. This study aimed to assess the concentrations of IL-1α and IL-12 in the PF of women with endometriosis compared to those with idiopathic infertility.