Autoimmune Disease

Our bodies are protected by the immune system, a network of different types of cells, tissues, and molecules with different functions that serve to defend the body from invasion and infection. The immune system is activated in response to antigens, proteins, or carbohydrates that evoke an immune response. These antigens can be to self or to a foreign substance. Autoimmune disease describes an illness in which the body’s immune system attacks healthy cells. This entry begins with an introduction to the immune system and discusses autoimmune diseases both generally and using case examples.