Histologic and Immunohistochemical Evaluation of 65 Placentas From Women With Polymerase Chain Reaction–Proven Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection

Abstract

Context.—Coronavirus disease 2019 (COVID-19) has been shown to have effects outside of the respiratory system. Placental pathology in the setting of maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remains a topic of great interest as earlier studies have shown mixed results. Objective.—To ascertain whether maternal SARS-CoV-2 infection is associated with any specific placental histopathology, and to evaluate the virus's propensity for direct placental involvement. Design.—Placentas from 65 women with polymerase chain reaction-proven SARS-CoV-2 infection underwent histologic evaluation using Amsterdam consensus group criteria and terminology. Another 85 placentas from women without SARS-CoV-2 constituted the negative control group. Sixty-four of the placentas from the SARS-CoV-2-positive group underwent immunohistochemical staining for SARS-CoV-2 nucleocapsid protein. Results.—Pathologic findings were divided into maternal vascular malperfusion, fetal vascular malperfusion, chronic inflammatory lesions, amniotic fluid infection sequence, increased perivillous fibrin, intervillous thrombi, increased subchorionic fibrin, meconium-laden macrophages within fetal membranes, and chorangiosis. There was no statistically significant difference in prevalence of any specific placental histopathology between the SARS-CoV-2-positive and negative groups. There was no immunohistochemical evidence of SARS-CoV-2 virus in any of the 64 placentas that underwent staining for viral nucleocapsid protein. Conclusions.—Our study results and a literature review suggest that there is no characteristic histopathology in the majority of placentas from women with SARS-CoV-2 infection. Likewise, direct placental involvement by SARS-CoV-2 is a rare event.

Association Between COVID-19 Pregnant Women Symptoms Severity and Placental Morphologic Features

“…Fetal vascular malperfusion (FVM) alterations have been described as well, such as focal thrombosis of fetal placental vessels ( 30 – 34 , 46 ). However, various authors did not identify a correlation between placental lesions and maternal infection, notably when the samples analyzed were obtained from uninfected placentas and infants ( 47 ).…”

“…Fetal vascular malperfusion (FVM) alterations have been described as well, such as focal thrombosis of fetal placental vessels (30)(31)(32)(33)(34)46). However, various authors did not identify a correlation between placental lesions and maternal infection, notably when the samples analyzed were obtained from uninfected placentas and infants (47). Interestingly, in cases with confirmed transplacental infection, inflammatory alterations were more frequently observed, particularly chronic histiocytic intervillositis with trophoblast necrosis.…”

Clinical and in Vitro Evidence against Placenta Infection at Term by Severe Acute Respiratory Syndrome Coronavirus 2

“…The SARS-Cov-2 strains were isolated from patient samples (clade 20E/EU1). Twenty-four hours or 96 h after isolation, the cells were exposed to three concentrations of viral particles (10 9 , 10 8 , 10 7 copies/mL). Two hours after, the cells were washed three times with PBS, and fresh medium was added.…”

“… 7 Direct involvement of the placenta is a rare event, and robust virological evidence, whether by RT-PCR, immunohistochemistry (IHC), or in situ hybridization (ISH), is most of the time missing in the reported cases. [8] , [9] , [10] However, some authors revived the debate by documenting intrauterine transmission and placental infection. [11] , [12] , [13] As SARS-CoV-2 has been detected in the blood of severely ill patients, circulating viral particles are likely to interact with the maternofetal interface.…”

SARS-CoV-2/COVID-19-Auswirkungen auf die Plazenta

“…("graft-versus-host-like") verweist [36]. Andere Studien hingegen halten eine chronische Villitis in Patientinnen ohne manifeste COVID-19-Erkrankung fest und berichten, im Vergleich zu adäquaten Kontrollkohorten, über keine gesteigerte Inzidenz der Villitis/Intervillositis [36][37][38][39]. Natürlich bleibt die chronische Villitis unklarer Ätiologie ("villitis of unknown origin") immer eine Differenzialdiagnose, jedoch scheint eine Assoziation "Entzündung & SARS-CoV-2" gerade auch im Hinblick auf die Morphologie anderer Virusinfektionen gut möglich.…”