Features of PDL-1 Expression in Abortive Tis- sues of Women with Non-Developing Pregnan- cies Associated with COVID-19 Infection

Abstract

Aim. To study the level of Pdl-1 receptor expression in abortive tissues from non-developing pregnancies associated with COVID-19 and to evaluate the correlation between Pdl-1 expression and the clinical course of the infection. Materials and methods. The study included 60 women with non-developing pregnancies associated with COVID-19 infection. Participants were divided into two groups: Group I consisted of 30 women with pregnancies of 5-7 weeks, terminated by vacuum aspiration; Group II included 30 women with pregnancies of 8-12 weeks, terminated by medical abortion. The control group comprised 30 women who terminated pregnancies of 6-12 weeks by choice. Results. The results of IHC analysis of abortive tissues in Group I showed focal Pdl-1 receptor expression in decidual tissue in 67% of cases, heterogeneous expression in chorionic villi in 58% of patients, and diffuse expression in syncytiotrophoblast in 54% of cases. In Group II, moderate Pdl-1 receptor expression in decidual tissue was found in 57% of samples. Focal expression in syncytiotrophoblast was observed in 53% of cases, and heterogeneous expression in chorionic villi was detected in 51% of cases. In the control group, Pdl-1 expression was significantly lower compared to both COVID-19 groups, indicating the virus’s impact on the immunohistochemical characteristics of the tissues.Conclusions. The study revealed a high level of Pdl-1 receptor expression in abortive tissues from both groups with non- developing pregnancies associated with COVID-19. This increased expression likely reflects the negative impact of SARS-CoV-2 on fetal tissues, possibly due to the virus entering and damaging these tissues. Additionally, a correlation was identi- fied between the level of Pdl-1 receptor expression and the severity of COVID-19’s clinical course. Specifically, a weak positive correlation was found between Pdl-1 expression levels and severe COVID-19 (r=0.24) and mild COVID-19 (r=0.14). This suggests that the severity of COVID-19 infection may be associated with Pdl-1 receptor expression levels in abortive tissues, potentially indicating a direct link to the immune response.