Then we performed binary logistic regression analysis to evaluate the correlation between severity of COVID-19 and other independent variables (age, lymphocyte count, median neutrophil count, CD16+56+ NK cells, CD3+ T cells, CD4+ T cells, CD8+ T cells, IL-2, IL-4, IL-6 and IL-10 level), the result showed that CD3+ T cells, CD4+ T cells, and CD8+ T cells were risk factors for the severity of COVID-19 patients with T2DM (Table 2). Here, CD4 is linked to COVID-19.