After analyzing the activation status and differentiated phenotypes of CD122+NKG2D+ bystander-activated CD8+ T cells in HFRS patients, we noticed that the IL-15-induced cytotoxic effects of bystander-activated CD8+ T cells on HTNV-infected endothelial cells could be blocked by the anti-NKG2D antibody. Here, KLRK1 is linked to hemorrhagic fever with renal syndrome.