These data are of special interest, as some studies identified a high frequency of NKG2A+ cells, and the high-level NKG2A expression, as a risk factor for the development and the prognosis of distinct malignant diseases, and for the severity of distinct viral infections, such as chronic hepatitis B, or with severe coronavirus disease 2019 (COVID-19) (32). Here, KLRC1 is linked to viral infectious disease.