Morphological changes of endometrial tissue in women with infertility who suffered from coronavirus disease anamnesis

The objective: to determine the morphological changes in endometrial samples in women with infertility and post-COVID syndrome.Materials and methods. 80 women with infertility and a history of post-COVID syndrome were examined, as well as 40 women with infertility without having experienced COVID-19.In all patients, endometrial samples were collected in the middle proliferative and middle secretory phases (in different menstrual cycles) by pipel biopsy or during office hysteroscopy, followed by histological and immunohistochemical examination. Antibodies to angiotensin-converting enzyme-2 (ACE2), SARS-CoV-2, CD138, CD56 were used for immunotyping.Results. In women with infertility and a history of post-COVID syndrome plasma cells (р = 0.027), lymphohistiocytic infiltration (р = 0.003), areas of fibrotic stroma (р=0.031) are more often detected during the study of endometrial samples in the middle proliferative phase, and in biosamples of the middle secretory phase – weakly developed stroma (p = 0.033), plasma cells (p = 0.029). When conducting an immunohistochemical study in both cohorts an increase in ACE2 protein expression was found in the middle secretory phase.In the mucous membrane of the uterus in both proliferative and secretory phase, in patients of both cohorts the expression of the CD138 immunomarker was detected, but in the middle secretory phase the signs of the expression of endometrial granulocytes were more often found in women who were diagnosed with infertility and a history of post-CIVOD syndrome (p=0.032). No expression of antibodies to SARS-CoV-2 was observed in the endometrial samples of patients who had coronavirus disease.Conclusions. In women with infertility and post-COVID syndrome the main morphological features in the selected endometrial samples were the presence of plasma cells in both phases of the menstrual cycle, lymphohistiocytic infiltration of the stroma, areas of fibrosis of the stromal component in the middle proliferative phase, impaired decidualization and expression of endometrial granulocytes in the middle secretory phase, and as well as the lack of expression of the SARS-CoV-2 immunomarker.