In Aging Cell, researchers have described why older natural killer (NK) cells lose their ability to eliminate harmful cells and a potential treatment for this decline.

Judgment and ability

At the cellular level, there is no due process. Natural killer (NK) cells judge other cells’ guilt or innocence by their surface proteins. They ruthlessly exterminate any foreign cells they find, which is what causes organ rejection; when they mistakenly attack the body’s own functional cells, autoimmune disorders are the result.