Macrophage polarization and PD-L1 expression in placentas with acute and post SARS-CoV-2 infection

Einleitung Since the beginning of the Covid-19 pandemic, numerous studies have shown that the virus poses a particular risk to pregnant women. Expectant mothers were more susceptible to severe illness and an increased mortality rate was also found in this patient group. In addition, an increased risk of pregnancy complications such as premature birth, intrauterine growth retardation, hypertension, stillbirth and neonatal developmental disorders was found. The aim of this study was to investigate the expression of CD68 and CD 163 as markers of macrophages and the immune checkpoint molecule PD-L1 on tissue sections from placentas.

Material und Methodik A total of 60 placentas from women who gave birth at Augsburg University Hospital between 2020 and 2022 were examined. We examined 10 placentas each female & male with acute Covid-19 infection, 10 placentas each female & male after Covid-19 infection and 10 placentas each female & male of a control group. Immunohistochemical staining against CD68, CD163 and PD-L1 was performed and the expression of the markers was assessed using the immunoreactive score (IRS). The identity of CD163- or PD-L1-expressing cells was confirmed by double immunofluorescence staining.

Ergebnisse CD163-positive maternal macrophages are significantly increased in the decidua of male acute Covid placentas. PD-L1 is significantly upregulated on male acute and post-Covid-19 decidual immune cells and on male post-Covid-19 extravillous trophoblast cells.

Zusammenfassung Surprisingly, the observed effects are associated with fetal sex, with the male sex being particularly affected. Further studies are needed to analyze in particular the formative effect of this infection.

Publication History

Article published online:
14 June 2024