Trophoblast damage with acute and chronic intervillositis: disruption of the placental barrier by severe acute respiratory syndrome coronavirus 2

• Published in: Human pathology Vol. 109; pp. 69 - 79
• Main Authors: Debelenko, Larisa, Katsyv, Igor, Chong, Alexander M., Peruyero, Leonore, Szabolcs, Matthias, Uhlemann, Anne-Catrin
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.03.2021; Elsevier Limited; Published by Elsevier Inc
• Subjects: Adult; Antibodies; Asymptomatic; Childbirth & labor; Cloning; Congenital diseases; Coronaviruses; COVID-19; COVID-19 - virology; Disease transmission; Female; Humans; Immunohistochemistry; In Situ Hybridization - methods; Infections; Microscopy; Original Contribution; Pathology; Placenta; Placenta - pathology; Placenta - virology; Pregnancy; qRT-PCR; RNA, Viral; SARS-CoV-2; SARS-CoV-2 - pathogenicity; Severe acute respiratory syndrome coronavirus 2; Trophoblasts - chemistry; Trophoblasts - pathology; Trophoblasts - virology; Vertical transmission; Viral Load; Iowa; Immunohistochemistry; Vertical transmission; SARS-CoV-2; Placenta; qRT-PCR
• ISSN: 0046-8177; 1532-8392; 1532-8392
• DOI: 10.1016/j.humpath.2020.12.004

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was demonstrated in the placenta; however, the data on the prevalence of placental infection and associated histopathology are limited. To identify the frequency and features of SARS-CoV-2 involvement, we performed a clinicopathologic analysis of 75 placental cases from women infected at the time of delivery and 75 uninfected controls. Placental samples were studied with anti–SARS-CoV-2 immunohistochemistry and/or in situ hybridization. Positive results were confirmed by electron microscopy and quantitative reverse-transcription polymerase chain reaction (qRT-PCR). During delivery, only one woman had symptoms of coronavirus disease 2019, six women reported previous symptoms, and 68 women were asymptomatic. All neonates tested negative for SARS-CoV-2 as per nasopharyngeal swab PCR results. Obstetric histories were unremarkable in 29 of 75 SARS-CoV-2–positive and 8 of 75 SARS-CoV-2–negative women. Placental examination was normal in 12 of 75 infected and 3 of 75 uninfected subjects, respectively. In the remaining cases, placental pathology correlated with obstetric comorbidities without significant differences between SARS-CoV-2–positive and SARS-CoV-2–negative women. SARS-CoV-2 was identified in one placenta of an infected, but asymptomatic, parturient. Viral staining was predominantly localized to the syncytiotrophoblast (STB) which demonstrated marked damage accompanied by perivillous fibrin deposition and mixed intervillositis. A significant decrease of viral titers was detected in the attached umbilical cord compared with the villous parenchyma as per qRT-PCR. SARS-CoV-2 is seldom identified in placentas of infected women. Placental involvement by the virus is characterized by STB damage disrupting the placental barrier and can be seen in asymptomatic mothers without evidence of vertical transmission. -Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) placental invasion is detected seldom at the time of delivery.-SARS-CoV-2 invades the villous trophoblast and disrupts placental barrier.-SARS-CoV-2 is associated with acute and chronic intervillositis.-SARS-CoV-2 placental invasion can be seen in asymptomatic infection.-SARS-CoV-2–caused disruption of the placental barrier is not always associated with vertical transmission of the infection to offspring.