Autoimmune disease results from the immune system attacking self-antigens and the loss of self-tolerance. Several different immunological mechanisms can be responsible. Autoimmune responses involve the generation of effector B and T cells that have specificity for a self-antigen. Autoreactive effector T cells may attack healthy tissue, recruiting inflammatory cells and mediators which cause direct tissue damage. Autoantibody production may also occur since B cell activation is heavily dependent on T cell interaction. Often the self-reactive T cells and autoantibodies work together to cause the clinical features of the disease.
Autoimmune diseases are usually grouped by location:
- Organ-specific autoimmune disease: The autoantibodies and T cells attack a specific organ.
- Example: Type 1 diabetes mellitus, where T cells damage the beta cells of the pancreas and autoantibodies are produced against the beta cells.
- Non-organ specific/systemic autoimmune disease: The autoantibodies attack multiple organ systems.
- Example: Systemic lupus erythematosus (SLE), where the autoantibodies may attack any organ in the body.
