TNF and COVID-19: The mechanism of the nervous system manifestations of COVID-19 may be that SARS-CoV-2-related cytokines such as IL-1b, IL-17, IL-6, and TNF alter the permeability of the blood-brain barrier, which makes SARS-CoV-2 can reach the brain and recognize ACE2 directly affects brain cells (Iadecola et al., 2020).