PMC10213910_01
Immunohistochemical staining for SARS-CoV-2 N-Protein (NP) and Hematoxylin and Eosin staining for histo-morphological evaluation (A) and H-Score (B) for placental and neonatal tissues. Non-COVID-19 placenta (A), membranes (B) and umbilical cord (C) have been used as negative control for stain specificity. H-Score comparisons of the different tissues versus the placenta were evaluated by student t-test and p-values were corrected for multiple comparisons by Bonferroni's correction. *p-value < 0.05. Magnification: 60x (upper line) and 100x (lower line).
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F1
Multiple sections slide of parenchyma, umbilical cord and membranes were stained by standard hematoxylin-eosin-stained for histological evaluation, revealing only small foci of ischemic necrosis and inconspicuous fibrinous material in the intervillous space were found (Supplementary Figure 1). The immunohistochemical examination showed positivity for SARS-CoV-2 NP in decidual placenta, but not in chorionic villi, and at lower extent in fetal membranes, at both amnion and chorion level (Figures 1A, B). On the contrary, we reported no SARS-CoV-2 NP positivity in umbilical cord (Figures 1A, B). His tissues were analyzed and showed a different positivity for SARS-CoV-2 NP (Figures 1A, B). Both organs presented a higher H-Score level compared to placenta (Figure 1B, p < 0.05, t-student test).