KLRC1 and lymphopenia: Our results are in line with the current body of literature, wherein we observed lymphopenia with more severe COVID-19, an increase in killing with NKG2A blockade, as well as a novel functional finding probing the efficacy of KIR2DL1 blockade with or without NKG2A blockade combination in vitro in improving COVID-19 derived NK cell antiviral cytotoxicity (9, 10, 12, 13).