NK cells can secrete various cytokines, such as IFN-γ, TNF-α, etc. Kaneko et al. found that excessive TNF-α inhibited the formation of germinal center reactions, suppressed the generation of long-lasting antibody responses originating from germinal centers, resulting in the low and transient antibody responses in COVID-19 patients [47]. The gene discussed is IFNG; the disease is COVID-19.