Moreover, in the COVID-19 DM subgroup, the lymphocyte counts and percentages (Fig. 3a, b), CD3+ cell counts (Fig. 4a), CD3+ CD4+ cell counts (Fig. 4c), CD3+ CD8 + cell counts (Fig. 4e), B(CD19+) cell counts and percentages (Fig. 5a, b) were lower, but NK (CD56+) cell counts and percentages (Fig. 6a, b) were higher than the corresponding values in the COVID-19 non-DM subgroup. Here, CD4 is linked to COVID-19.