In addition, there no significant difference in other T8 lymphocyte subsets, including effector memory T8 cells, effector T8 cells, CD27− differentiated T8 cells, CD28− differentiated T8 cells, CD57+ differentiated T8 cells, and PD1+ depleted T8 cells, between mild, severe and critical COVID-19 patients (Fig. 3C). This evidence concerns the gene CD28 and COVID-19.