Hofbauer cells and coronavirus disease 2019 (COVID-19) in pregnancy: Molecular pathology analysis of villous macrophages, endothelial cells, and placental findings from 22 placentas infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with and without fetal transmission

David A Schwartz, Marcella Baldewijns, Alexandra Benachi, Mattia Bugatti, Gaetano Bulfamante, Ke Cheng, Rebecca R J Collins, Larisa Debelenko, Danièle De Luca, Fabio Facchetti, Brendan Fitzgerald, Daniel Levitan, Rebecca L Linn, Lukas Marcelis, Denise Morotti, Raffaella Morotti, Luisa Patanè, Sophie Prevot, Bianca Pulinx, Ali G SaadSam Schoenmakers, David Strybol, Kristen Thomas, Delfina Tosi, Valentina Toto, Lotte E van der Meeren, Robert M Verdijk, Alexandre J Vivanti, Mehreen Zaigham

Research output: Contribution to journalArticlepeer-review

Abstract

CONTEXT: - Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can undergo maternal-fetal transmission, heightening interest in the placental pathology findings from this infection. Transplacental SARS-CoV-2 transmission is typically accompanied by chronic histiocytic intervillosaaitis together with necrosis and positivity of syncytiotrophoblast for SARSCoV-2. Hofbauer cells are placental macrophages that have been involved in viral diseases including HIV and Zika virus, but their involvement in SARS-CoV-2 in unknown.

OBJECTIVE: - To determine whether SARS-CoV-2 can extend beyond the syncytiotrophoblast to enter Hofbauer cells, endothelium and other villous stromal cells in infected placentas of liveborn and stillborn infants.

DESIGN: - Case-based retrospective analysis by 29 perinatal and molecular pathology specialists of placental findings from a preselected cohort of 22 SARS-CoV-2-infected placentas delivered to pregnant women testing positive for SARS-CoV-2 from 7 countries. Molecular pathology methods were used to investigate viral involvement of Hofbauer cells, villous capillary endothelium, syncytiotrophoblast and other fetal-derived cells.

RESULTS: - Chronic histiocytic intervillositis and trophoblast necrosis was present in all 22 placentas (100%). SARS-CoV-2 was identified in Hofbauer cells from 4/22 placentas (18%). Villous capillary endothelial staining was positive in 2/22 cases (9%), both of which also had viral positivity in Hofbauer cells. Syncytiotrophoblast staining occurred in 21/22 placentas (95%). Hofbauer cell hyperplasia was present in 3/22 placentas (14%). In the 7 cases having documented transplacental infection of the fetus, 2 occurred in placentas with Hofbauer cell staining positive for SARS-CoV-2.

CONCLUSIONS: - SARS-CoV-2 can extend beyond the trophoblast into the villous stroma, involving Hofbauer cells and capillary endothelial cells, in a small number of infected placentas. Most cases of SARS-CoV-2 transplacental fetal infection occur without Hofbauer cell involvement.

Original languageEnglish
Pages (from-to)1328-1340
JournalArchives of pathology & laboratory medicine
Volume145
Issue number11
Early online date2021 Jul 23
DOIs
Publication statusPublished - 2021

Subject classification (UKÄ)

  • Infectious Medicine

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