In the DEGs-miRNAs interaction network of COVID-19 and AD, FKBP5, SEZ6L2, VGF, PCSK1 and hsa-miR-1-3p, hsa-miR-27a-3p, hsa-miR-155-5p, hsa-miR-34a-5p were significantly expressed, see Figure 5A. In the DEGs-miRNAs interaction network of COVID -19 and the DEGs-TFs interaction network of PD, STOM, IFITM2, SAT1 and PLP2 were significantly expressed, and FOXC1, GATA2 and RELA were important partial TFs. Here, PLP2 is linked to COVID-19.