Figure 4.

Immunohistochemical staining patterns of ACE2 in COVID-19-affected brain samples. Two representative images for each of the nine different regions of COVID-19-affected brain samples available for all three postmortem patients. Similar to the normal brain, distinct positivity was observed in ependymal cells (black arrows), choroid plexus cells (black and white arrows), and endothelial cells of the choroid plexus (double arrows). The expression of endothelial cells was upregulated in Patient 1 and 2 with the most abundant staining seen in Patient 1 generally in smaller vessels of white matter (black needle).