Likewise, since IL-2 is a double-faced cytokine also exerting immunoregulatory activities maintaining Treg cells in a functional state,102,103,104 its reduced plasma concentrations might also have a role in exacerbating cytokine storm and heightening T cell cytotoxicity, likely due to perturbations in Treg cells, which has been indeed proven in severe COVID-19.105. This evidence concerns the gene IL2 and COVID-19.