From the cell to the body as a whole, a fundamental characteristic of living units is the ability to distinguish inside from outside. The job of immune system is to decide when something should be taken in and made a part of us, or whether it should be kept out or if found on the inside, destroyed. Immune systems can be compromised when these boundaries aren’t functioning properly, and foreign materials are wreaking havoc. Autoimmune conditions develop when the immune system is so out of balance that parts of us are damage in the crossfire.