Our study identified a potential biomarker molecule, MACROH2A1, which has a fluctuating expression in cells of the monocyte lineage; this forms the basis of innate immune responses, suggesting the involvement of MACROH2A1 in the pathogenesis of COVID-19 that do not change with shifts in epidemic strains due to the emergence of mutant strains, although this hypothesis needs verification, in the future. Here, MACROH2A1 is linked to COVID-19.