Immunohistochemical investigation of cytokeratin-8 and Ki-67 protein expressions in COVID-19 placentas

Aim: The aim of our study is to examine the placental histopathological structure of the placentas of pregnant patients with COVID-19 by using cytokeratin-8 and Ki-67 antibodies. Materials and methods: In our study, small pieces were taken for histological follow-up from the placentas of 20 pregnant women and 20 normotensive patients who were hospitalized in Dicle University Faculty of Medicine, Gynecology and Obstetrics Clinic and diagnosed with COVID-19. Placenta samples were stained with Hematoxylin-Eosin, cytokeratin-8 and Ki-67 immunohistochemistry staining and examined under a light microscope. Results: Normal histology appeared in control placentas. Thinning of the chorionic villi and syncytial bridges was observed in the placenta samples of COVID-19 patients. Enlarged syncytial nodes in the chorionic villi and a significant increase in connective tissue cells and aggregate formation of inflammatory cell infiltration were observed. Dilated blood vessels and endothelial structure were observed to be disrupted. Freely dispersed erythrocyte invasion and leukocytes were seen in the intervillous space. Increased expression of cytokeratin 8 was seen in decidual, fibroblast and inflammatory, hofbauer cells, cytotrophoblasts and syncytial nodes. Ki-67 expression was positive in chorionic villi, syncytial nodes, cytotrophoblast cells, Hofbauer cells and inflammatory cells. Conclusion: It was concluded that the structural integrity of the basement membrane in syncytial nodes and bridges is impaired due to COVID-19, that the expression of Ki-67 may be an important marker in showing the increase in inflammation, and that the increase in cell degeneration and cytokeratin8 expression is effective in explaining the course of COVID-19.