Patients with severe COVID-19 exhibit lymphopenia with reduction in CD4+ and CD8+ T cells, lymphocyte activation and dysfunction, an increase in circulating neutrophils with the appearance of circulating neutrophil precursors, dysfunction of classical monocytes and loss of non-classical monocytes, reduced abundance and dysfunction of DCs and NK cells (22, 27, 28). The gene discussed is CD4; the disease is COVID-19.