HDAC2 and COVID-19: To further verify our analysis results, we found that the 451 targets of XBJ (Supplementary file, Table S1) and 332 putative COVID-19-interacting human protein had fourteen intersections: BRD2, BRD4, IMPDH2, POLA1, ATP6AP1, SIGMAR1, HMOX1, DNMT1, HDAC2, PABPC1, EIF4H, PRKACA, ABCC1, and COMT.