TMPRSS2 and Alzheimer disease: To get an insight on whether cerebral cortical cells in individuals who are potentially vulnerable to neurological complications of COVID-19 (e.g., DS persons) differ from less vulnerable group in their expression of main SARS-CoV-2 interactors and/or the ISGs, we compared the protein levels of ACE2, TMPRSS2, STAT1, and STAT2 in homogenates prepared from postmortem specimens of entorhinal cortex of non-AD aged controls, age-matched subjects with AD, and DS-AD subjects.