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.