Abstract
Introduction: Endometriosis is a chronic inflammatory disease affecting women of reproductive age, often accompanied by chronic pelvic pain and infertility. Despite numerous studies, its pathogenesis remains incompletely understood. Increasing evidence indicates the important role of immunological disorders, especially in the mechanisms of innate immunity and Toll-like receptors (TLRs). Study objective: This study aimed to assess the expression of selected TLRs (TLR2, TLR3, TLR4, TLR7, TLR8, and TLR9) on peripheral blood lymphocyte subpopulations (CD4+, CD8+, and CD19+ cells) in patients diagnosed with endometriosis and to quantify the levels of their soluble forms in serum and urine. This study was conducted on patients who were not undergoing hormonal bridging therapy and were not using any form of hormonal contraception to eliminate potential confounding effects on immune parameters. Methods: Flow cytometric analysis of TLR expression on peripheral blood lymphocytes was performed, and the levels of their soluble forms in serum and urine samples were determined. Additionally, ROC curve analysis was used to evaluate the diagnostic potential of the studied parameters. Results: We found increased expression of TLRs in lymphocyte populations in patients with endometriosis compared to the control group, suggesting their involvement in both local and systemic immune responses. In addition, ROC analysis showed the diagnostic potential of TLR expression in differentiating patients with endometriosis from healthy women, and it may also identify disease subtypes. Conclusions: The findings support the role of TLRs in the immunopathogenesis of endometriosis and highlight their promise as diagnostic biomarkers and therapeutic targets. Further studies on larger patient cohorts and functional signaling analyses are warranted.