CD4 and diabetes mellitus: Furthermore, the numbers of CD4+ T cells and CD8+ T cells were reduced below the lower limit of normal (LLN) in the vast majority of patients with diabetes with COVID-19, and the medians of the diabetic group were reduced more profoundly than in the non-diabetic group (204.0 vs. 583.0 ×106/L, P=0.007 and 115.0 vs. 352 ×106/L, P=0.002, respectively).