Bump your levels of this to above 10% and you’ll make your body virtually flu-proof – causing these cells to basically chew up and spit out any infected cells it is in contact with. Here are 9 simple ways to ramp up your levels. Story at-a-glance Natural killer (NK) cells are a specific type of white blood cell. They’re an important component of your cell-mediated (innate) immune system and are involved in both viral diseases and cancer NK cells are cytotoxic; they induce apoptosis (programmed cell death), which destroys the virus along with the infected cell NK cells — which are not antigen-specific — contain the infection while your adaptive, humoral immune response generates T cells containing antigen-specific cytotoxins to clear the infection KLRD1 is a receptor gene found on the surface of NK cells, and the level of KLRD1 found in a person’s blood prior to exposure to the influenza …