Untimely TGFβ responses in COVID-19 limit antiviral functions of NK cells

Natural killer (NK) cells are involved in the control of viral load in COVID-19 cases. In the severe case, NK cells showed reduced functions for virus control, cytokine production and cell-mediated cytotoxicity. Genes related to cell-cell adhesion, granule exocytosis and cell- mediated cytotoxicity were impaired in the NK cells of severe COVID-19 cases. The expression of TGFβ that showed inhibitory effect for NK cell activation was well-correlated with the disease severity.