Different phenomena, not mutually exclusive, might be involved: (1) direct infection of T-lymphocyte by SARS-CoV-2 (through the cellular receptor basigin [BSG/CD147]) and consequent cytolysis or apoptosis27; (2) lymphocyte migration in the lungs, as assessed by histochemical studies from fatal cases28,29; and (3) exhaustion of circulating T-cells of severe COVID-19 patients, characterized by reduced replicative abilities upon stimulation30,31. Here, BSG is linked to infection.