Abstract
OBJECTIVES: Endometriosis (EM), a prevalent estrogen-dependent inflammatory disorder affecting women of reproductive age, is characterized by the presence of endometrial-like tissue outside the uterus, resulting in pelvic scarring, pain, and infertility. Although the pathogenesis of EM remains poorly understood, there is growing evidence suggesting the involvement of the immune system in its etiology, pathophysiology, and associated morbidities such as pain, infertility, and adverse pregnancy outcomes. While previous studies have indicated a close relationship between the immune system and EM, the specific underlying mechanism remains incompletely elucidated. METHODS: Through the utilization of publicly available genetic data, a two-sample Mendelian randomization (MR) analysis was conducted to establish an association between 731 immune cell phenotypes and EM. Comprehensive sensitivity analyses were performed to validate the robustness, heterogeneity, and potential horizontal pleiotropy of the findings. RESULTS: The MR analysis revealed potential associations between 22 immune cell phenotypes and EM. Conversely, reverse MR analysis identified 11 immune phenotypes demonstrating potential associations between genetic liability in the immune phenotypes and EM. CONCLUSION: This study provides evidence of a potential correlation between immune cell phenotypes and EM, including the existence of reverse causation. These findings open up new avenues for investigating the underlying mechanisms of EM.