Fig 1: Neuropathology of SARS-CoV-2 Infection in a Patient With Epilepsy(A) H&E and immunostaining (fibrinogen, PECAM-1, and CD68) of perivascular region of temporal cortical biopsy from a patient with COVID-19. Scale bars are 50 µm. (B) H&E and fibrinogen immunostaining of the biopsy tissues from the patient and fibrinogen immunostaining of control tissue. Bottom 4 panels are representative images of observed perivascular fibrinogen leakage. Scale bars are 3 mm (upper) 100 µm (lower). (C) PECAM-1 expression was significantly greater in the patient compared with uninfected controls and statistically different (*p = 0.0270). For quantification, PECAM-1 levels were assessed using ImageScope software (Leica Biosystems). One hundred small blood vessels per section were selected. The area of the entire vessel and lumen area were measured by tracing the contours of the entire vessel and lumen within the vessel. PECAM-1 expression area was determined by subtracting luminal area from entire vessel area. To exclude the effect of vessel size, the PECAM-1 area was normalized by dividing it by the blood vessel area. Data represent mean areas of PECAM-1 expression (µm2). Scale bars are 50 µm. (D) GFAP immunostaining of the perivascular regions in the patient with COVID-19. Scale bars are 100 µm. (E) Neurons surrounded by microglia clusters were shown in H&E, CD68, and TMEM119-stained COVID-19 patient's biopsy tissue. Scale bars are 200 µm. (F) Clusters of CD68+ microglia surrounding neurons (neuronophagia) were absent in the brain of controls but present in the brain of patient. The number of foci of neuronophagia was significantly increased in the brain of patient compared with controls (p < 0.0001). Quantification of neuronophagia was performed by counting the number of CD68+ clusters. Values were expressed by the average number of foci of neuronophagia per section (#/section). Scale bars are 100 µm. (G) Immunostaining of the parenchyma (top row), perivascular region (middle row), and meninges (bottom row) for CD3, CD4, CD8, and CD20 in the patient with COVID-19. Scale bars are 50 µm. (H) The CD8+ T cells were present in greater numbers in the brain of patient, predominantly in the perivascular (PV) regions. The number of CD8+ T cells were significantly increased in both parenchymal (*p = 0.0344) and perivascular (**p = 0.0023) regions of patient compared with controls. For quantification of CD8+ cells, 50 regions of each stained brain section were randomly selected, and the number of positive cells was counted. Each area was 0.4 mm2. Values represented the average number of cells per volume (#/mm3). Scale bars are 50 µm. Antibodies used for staining: fibrinogen (Abcam, ab58207), PECAM-1 (Leica Biosystems, CD31-607-L-CE), CD68 (Thermo Fisher Scientific, 14-0688-82), TMEM119 (Novus Biologicals, CL8714), GFAP (Dako, Z0334), CD3 (Leica Biosystems, CD3-565-L-CE), CD4 (Leica Biosystems, CD4-368-L-CE), CD8 (Leica Biosystems, CD8-4B11-L-CE), and CD20 (Leica Biosystems, CD20-L26-L-CE). PECAM = platelet endothelial cell adhesion molecule-1