Expression of NKG2A inhibitory receptor on cytotoxic lymphocytes as an indicator of severity in Corona Virus Disease 2019 (COVID-19) patients.

NK group 2 member A (NKG2A) receptor transduces inhibitory signaling; suppressing NK and T-cell cytokine secretion and cytotoxic function. This study aimed to assess the expression of NKG2A inhibitory receptor on natural killer (NK) cells and CD8+ T lymphocytes in COVID-19 patients and correlate the results with disease severity defined according to the criteria established by the world health organization, in a trial to understand the immunological response towards COVID-19 infection. The study enrolled 30 COVID-19 patients classified into 2 groups that comprised 15 subjects each; moderate and severe based on clinical, radiological, and laboratory findings.