The first step of understanding autoimmunity is to understand your immune system. The immune system is the body’s defence against invaders and other foreign objects. Through a series of steps called the immune response, your immune system attacks those invaders.

When the immune system detects an invader, several types of cells work together to recognize the invader and to respond by producing antibodies. Antibodies lock onto the invader, but can not destroy it without help. That is the job of the T cells, which is also called the “killer cells”. These killer cells destroy invaders that have been tagged by antibodies and also help signalling other cells to do their jobs.

All of these specialised cells are part of the immune system and protect the body against disease. This protection is called immunity.

Autoimmunity happens when your immune system can no longer tell “self” from “non-self”. Your immune system sees your own cells as invaders and trigger an immune response to attack those cells.

Autoimmune diseases all look different but have one thing in common, an immune system that attacks your own cells. For some the thyroid is under attack, for others the intestines, the skin, the brain and many other organs. No matter what part of your body is under attack, the problem does not necessarily lie with that part of the body, but rather with the immune system.