CD4 and viral infectious disease: In patients with COVID-19, we found immune cells from myeloid lineage (M1 macrophages, neutrophils, and MAST cells) increased significantly (FDR ≤10%) and lymphoid cells (CD4+ and CD8+ alpha-beta T cells, B cells) decreased significantly (FDR ≤10%) during viral infection (Figure 6A, Table S4).