IL-6 can substantially contribute to the dysregulation of the immune response in COVID-19, basically by acting in two directions: on one side, it may cause a dysfunction of natural killer and cytotoxic CD8+ T cells associated with perforin and granzyme down-regulation (18), thereby dampening antiviral defenses; on the other side, it may inhibit the differentiation of regulatory T cells and elicit a T helper 17 (TH17)-like polarization of γ/δ and α/β CD4+ T cells, thus leading to uncontrolled hyperinflammation (7). Here, CD4 is linked to COVID-19.