Incubation of MDSCs from COVID-19 patients with either autologous CD4 + T cells or autologous CD8 + T cells gave a more significant reduction in the level of intracellular IFN-γ expression than observed with homologous CD4 + and CD8 + T cells (Fig. 4A P = 0.02 and Fig. 4B P = 0.03, respectively) despite similar levels of induction. Here, CD4 is linked to COVID-19.