Hofbauer Cells and COVID-19 in Pregnancy.

TitleHofbauer Cells and COVID-19 in Pregnancy.
Publication TypeJournal Article
Year of Publication2021
AuthorsSchwartz DA, Baldewijns M, Benachi A, Bugatti M, Bulfamante G, Cheng K, Collins RRJ, Debelenko L, De Luca D, Facchetti F, Fitzgerald B, Levitan D, Linn RL, Marcelis L, Morotti D, Morotti R, Patanè L, Prevot S, Pulinx B, Saad AG, Schoenmakers S, Strybol D, Thomas K, Tosi D, Toto V, van der Meeren LE, Verdijk RM, Vivanti AJ, Zaigham M
JournalArch Pathol Lab Med
Date Published2021 Nov 01
KeywordsAdult, Cell Proliferation, COVID-19, Endothelium, Female, Humans, Hyperplasia, Infant, Newborn, Infectious Disease Transmission, Vertical, Macrophages, Male, Placenta, Pregnancy, Pregnancy Complications, Infectious, Retrospective Studies, SARS-CoV-2, Stillbirth, Trophoblasts

CONTEXT.—: 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 intervillositis together with necrosis and positivity of syncytiotrophoblast for SARS-CoV-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 is 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 were present in all 22 placentas (100%). SARS-CoV-2 was identified in Hofbauer cells from 4 of 22 placentas (18.2%). Villous capillary endothelial staining was positive in 2 of 22 cases (9.1%), both of which also had viral positivity in Hofbauer cells. Syncytiotrophoblast staining occurred in 21 of 22 placentas (95.5%). Hofbauer cell hyperplasia was present in 3 of 22 placentas (13.6%). In the 7 cases having documented transplacental infection of the fetus, 2 (28.6%) 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.

Alternate JournalArch Pathol Lab Med
PubMed ID34297794
Related Faculty: 
Daniel Levitan, M.D.


Pathology & Laboratory Medicine 1300 York Avenue New York, NY 10065 Phone: (212) 746-6464
Surgical Pathology: (212) 746-2700