IFNG and Menkes disease: Figure 4A shows that, after PMA/Ionomycin stimulation, CD8lo T cell populations from HD as well as from SARS-CoV-2 infected patients (MD and SD) exhibited a lower frequency of the effector cytokine-producing cells, TNF, IL-2, and IFN-γ, than CD8hi T cells. The significant differences in both populations from the groups evaluated were confirmed by statistical analysis (Figure 4A). We found that SD patients exhibited a higher frequency of CD8hi T cells expressing IL-2 compared to MD patients. We did not find differences in the expression of other cytokines such as TNF and INFγ (Figure 4A).