It has been well established that CD4+ and CD8+ T cells specific for the peptide pools derived from N, M, and S SARS-CoV-2 proteins are detected in the blood of patients with COVID-19.37 M protein-reactive CD4+ T cells are the most polyfunctional with increased frequencies of IFN-γ, IL-2, and TNF-α, followed by S protein- and finally N protein-reactive CD4+ T cells. The gene discussed is CD4; the disease is COVID-19.