Acute Endotheliitis (Type 3 Hypersensitivity Vasculitis) in Ten COVID-19 Autopsy Brains

Central nervous system (CNS) involvement in COVID-19 may occur through direct SARS-CoV-2 invasion through peripheral or cranial nerves or through vascular endothelial cell infection. The renin-angiotensin system may play a major part in CNS morbidity. Effects of hypoxia have also been implicated in CNS lesions in COVID-19. This communication reports on ten consecutive autopsies of individuals with death due to COVID-19 with decedent survival ranging from 30 minutes to 84 days after admission. All ten brains examined had neutrophilic microvascular endotheliitis present in variable amounts and variably distributed. Importantly, this acute stage of type 3 hypersensitivity vasculitis can be followed by fibrinoid necrosis and inner vascular wall sclerosis, but these later stages were not found. These results suggest that a vasculitis with autoimmune features occurred in all ten patients. It is possible that viral antigen in or on microvascular walls or other antigen-antibody complexes occurred in all ten patients proximate to death as a form of autoimmune vasculitis.