Using a single-cell lung atlas of severe COVID-19 (containing 7 healthy non-COVID-19 controls who underwent lung resection or biopsy and 19 individuals with lethal COVID-19)47, we found that lung monocytes and macrophages had the highest expression of FTH1 and FTL compared to other immune and structural cells in the lung (Figure 1D–E). This evidence concerns the gene FTH1 and COVID-19.