CD55 and Alzheimer disease: As we reported, the expression levels of some key genes (including IRF7, STAT2, OAS1, LCN2, LGAS9, DAPP1, IFITM2, TRIM21, CD55, S100P, IRAK3, and IFIH1) were significantly up-expressed in both AD and COVID-19 patients, with some of them also being evidenced by several other studies [13,18,110], which highlights the critical roles of immune response factors in neuroinflammation in AD patients with COVID-19.