CD8A and COVID-19: Furthermore, in contrast with an increase in both IFN-α and IFN-γ plasma levels, detected in the peripheral blood of COVID-19 patients at the onset of infection, a reduction in the expression of Interferon gamma receptor 1 (IFNGR1) in COVID-19-derived B cells and CD8+ naïve T cells was also detected, suggesting that the sensitivity of immune cells to inflammatory signal molecules might be lower during the infection and that an interferon-based treatment [54] may not be effective for all patients with mild to severe COVID-19.