RBFOX3 and COVID-19: Analyzing the causes of NeuN-positive staining of the cytoplasm of brain neurons of patients who died of COVID-19, we cannot exclude the association of this phenomenon with hypoxic damage to neurons and neuronal dysfunction, as in HIV-1 disease, but postmortem changes involving autolysis and abnormal permeability of biological membranes, including the nuclear one, should also be considered.