For a long time researchers figured the body had a tidy way of dealing with immune cells that might trigger diabetes, lupus or other autoimmune diseases—it must kill off these rogue cells early in life, before the immune system matures. New research published on May 19 in Immunity challenges this age-old thinking. Instead, the body seems to keep these so-called self-reactive T cells in benign form to fight potential invaders later.

New research out of Stanford debunks some of our longest-held ideas about the behaviors of T cells