Definition of Autoimmune disorders
The word "auto" is the Greek word for self. The immune system is a
complicated network of cells and cell components (called molecules) that normally
work to defend the body and eliminate infections caused by bacteria, viruses, and other
invading microbes. If a person has an autoimmune disease, the immune system mistakenly
attacks self, targeting the cells, tissues, and organs of a person's own body. A
collection of immune system cells and molecules at a target site is broadly referred to as
There are many different autoimmune diseases, and they can each affect the body in
different ways. For example, the autoimmune reaction is directed against the brain in
multiple sclerosis and the gut in Crohn's disease. In other autoimmune diseases such as
systemic lupus erythematosus (lupus), affected tissues and organs may vary among
individuals with the same disease. One person with lupus may have affected skin and joints
whereas another may have affected skin, kidney, and lungs. Ultimately, damage to certain
tissues by the immune system may be permanent, as with destruction of insulin-producing
cells of the pancreas in Type 1 diabetes mellitus.
Description of Autoimmune disorders
Autoimmunity is accepted as the cause of a wide range of disorders, and it is suspected
to be responsible for many more. Autoimmune diseases are classified as either general, in
which the autoimmune reaction takes place simultaneously in a number of tissues, or organ
specific, in which the autoimmune reaction targets a single organ.
Autoimmune disorders include the following:
- Systemic lupus erythematosus. A general autoimmune disease in which antibodies attack a
number of different tissues. The disease recurs periodically and is seen mainly in young
and middle-aged women.
- Rheumatoid arthritis. Occurs when the immune system attacks and destroys the tissues
that line bone joints and cartilage. The disease occurs throughout the body, although some
joints may be more affected than others.
- Goodpasture's syndrome. Occurs when antibodies are deposited in the membranes of both
the lung and kidneys, causing both inflammation of kidney glomerulus (glomerulonephritis)
and lung bleeding. It is typically a disease of young males.
- Grave's disease. Caused by an antibody that binds to specific cells in the thyroid
gland, causing them to make excessive amounts of thyroid hormone.
- Hashimoto's thyroiditis. Caused by an antibody that binds to cells in the thyroid gland.
Unlike in Grave's disease, however, this antibody's action results in less thyroid hormone
- Pemphigus vulgaris. A group of autoimmune disorders that affect the skin.
- Myasthenia gravis. A condition in which the immune system attacks a receptor on the
surface of muscle cells, preventing the muscle from receiving nerve impulses and resulting
in severe muscle weakness.
- Scleroderma. Also called CREST syndrome or progressive systemic sclerosis, scleroderma
affects the connective tissue.
- Autoimmune hemolytic anemia. Occurs when the body produces antibodies that coat red
- Autoimmune thrombocytopenic purpura. Disorder in which the immune system targets and
destroys blood platelets.
- Polymyositis and Dermatomyositis. Immune disorders that affect the neuromuscular system.
- Pernicious anemia. Disorder in which the immune system attacks the lining of the stomach
in such a way that the body cannot metabolize vitamin B12.
- Sjögren's syndrome. Occurs when the exocrine glands are attacked by the immune system,
resulting in excessive dryness.
- Ankylosing spondylitis. Immune-system induced degeneration of the joints and soft tissue
of the spine.
- Vasculitis. A group of autoimmune disorders in which the immune system attacks and
destroys blood vessels.
- Type I diabetes mellitus. May be caused by an antibody that attacks and destroys the
islet cells of the pancreas, which produce insulin