Eutopic endometrial interleukin-18 system mRNA and protein expression at the level of endometrial-myometrial interface in adenomyosis patients

Objective: To investigate the eutopic endometrial interleukin-18 (IL-18) system including interleukin-18 (IL-18), IL-18 receptor (IL-18R), and IL-18 binding protein (IL-18BP), mRNA, and protein expression in patients with adenomyosis. Design: A clinical and molecular study. Setting: Clinical and academic research setting in a university medical center. Patient(s): Twenty-eight samples of human eutopic endometria were obtained from surgical specimens of normal cycling women undergoing hysterectomy for uterine adenomyosis (n = 19); the control group (n = 9) was women undergoing hysterectomy for benign reason including uterine fibroids. Intervention(s): Quantitative competitive polymerase chain reaction (QC PCR) and immunohistochemistry studies were performed. Main Outcome Measurement(s): The differences of the IL-18 system mRNA and the ratio of IL-18BP to IL-18 in the eutopic endometrium of uterine adenomyosis and control group were analyzed. Result(s): IL-18 system mRNA and protein expression was demonstrated in the eutopic endometrium of both adenomyosis and control women. Quantitative competitive PCR demonstrated that endometrial IL-18R mRNA and the ratio of IL-18BP to IL-18 were significantly increased in adenomyosis patients in comparison to the control group. Pearson's correlation showed a significant correlation between IL-18 and IL-18R in the eutopic endometrium of women with uterine adenomyosis, but not the control group. Conclusion(s): The expression of the eutopic endometrial IL-18 system and the ratio of antagonist to agonist at the level of the endometrial-myometrial interface (EMI) may possibly be responsible for the pathologic process of adenomyosis.