Presence of SARS-CoV-2 Transcripts in the Choroid Plexus of MS and Non-MS Patients With COVID-19

(A–B) Macroscopically visible lesions were assessed by (A) H&E, LFB staining, and MBP, Iba1, CD45, and (B) dysferlin immunohistochemical evaluation. Given the lack of ongoing myelin phagocytosis presence of Iba1⁺ macrophages, all examined lesions were staged as chronic-inactive. Scale bar indicates 100 μm. (C) Assessing the presence and spatial distribution of severe acute respiratory syndrome coronavirus-2 (SARS-COV-2) transcripts by in situ hybridization in MS COVID-19 compared with non-COVID-19 tissue, we found presence of SARS-CoV-2 transcripts (pink arrows) in lung tissue, ependymal cells, and choroid plexus (CP) epithelial cells from MS-COVID-19 in comparable amount with non-MS COVID-19 CP epithelial cells with some coexpression of ACE2 (white arrows). Notably, SARS-CoV-2 transcripts were not present in MS lesions areas, suggesting CP epithelial cells as a key constraint of viral CNS entry. Arrows indicate positive cells. Left and right panel show different areas of the respective tissue section. Scale bar indicates 20 μm. COVID-19 = coronavirus disease 2019; H&E = hematoxylin and eosin; LFE = luxol fast blue; MBP = myelin basic protein; PV = periventricular; WM = white matter.