Abstract
There is growing evidence that changes in the eutopic endometrial immune profile are a cause of endometriosis-associated infertility. Women affected by endometriosis experience a 2-fold increased risk of infertility compared to healthy controls. In our study we aimed to map out endometrial expressions of uterine natural killer cells, plasma cells, macrophages and the chemokine CXC-motif ligand 1 (CXCL1) as well as its main receptors CXC-motif receptor 2 (CXCR2) and Syndecan-1 in infertility-patients with endometriosis. 36 infertility patients were included of which 19 suffered from endometriosis and 17 served as a control cohort. All patients underwent endometrial scratching in the secretory phase and immunohistochemical staining which was evaluated by three independent observers. In endometriosis-patients, a higher concentration of macrophages coincided with an elevated number of uterine natural killer cells or plasma cells. Patients with endometriosis also showed a higher endothelial expression of VEGF-A. Furthermore, absence of stromal expression of SDC-1 was associated with an elevated level of uNK in general. Therefore, our study links endometriosis to an altered immune cell population in the eutopic endometrium, which might be a new approach to diagnosing endometriosis in infertility patients.