Autoimmune diseases are disorders in which the body's immune system reacts against some of its own tissue and produces antibodies to attack itself.

To better understand autoimmune diseases, one must understand how the immune system works.

The immune system is a network of organs, cells and molecules that work together to defend the body against attacks by foreign (not of the body) invaders such as germs, bacteria, viruses, parasites and fungi. When one of these invaders (antigens) tries to break...