The spleen volume of COVID-19 patients is significantly reduced, and the number of CD4+ T cells and CD8+ T cells in the spleen and peripheral lymph nodes is also reduced; such effects are accompanied by tissue degeneration and necrosis as well as a proliferation of macrophages, which are specifically like those noted with SARS-CoV infection [14–16]. The gene discussed is CD4; the disease is severe acute respiratory syndrome.