autoimmune disorders

What are autoimmune disorders?
Autoimmune disorders are diseases caused by the body producing an inappropriate immune response against its own tissues. Sometimes the immune system will cease to recognize one or more of the body’s normal constituents as “self” and will create autoantibodies – antibodies that attack its own cells, tissues, and/or organs. This causes inflammation and damage and it leads to autoimmune disorders.

The cause of autoimmune diseases is unknown, but it appears that there is an inherited predisposition to develop autoimmune disease in many cases. In a few types of autoimmune disease (such as rheumatic fever), a bacteria or virus triggers an immune response, and the antibodies or T-cells attack normal cells because they have some part of their structure that resembles a part of the structure of the infecting microorganism.

Autoimmune disorders fall into two general types: those that damage many organs (systemic autoimmune diseases) and those where only a single organ or tissue is directly damaged by the autoimmune process (localized). However, the distinctions become blurred as the effect of localized autoimmune disorders frequently extends beyond the targeted tissues, indirectly affecting other body organs and systems. Some of the most common types of autoimmune disorders include:

Systemic Autoimmune Diseases	Localized Autoimmune Diseases
Rheumatoid arthritis (RA) and Juvenile RA (JRA) (joints; less commonly lung, skin)	Type 1 Diabetes Mellitus (pancreas islets)
Lupus [Systemic Lupus Erythematosus] (skin, joints, kidneys, heart, brain, red blood cells, other)	Hashimoto's thyroiditis, Graves' disease (thyroid)
Scleroderma (skin, intestine, less commonly lung)	Celiac disease, Crohn's disease, Ulcerative colitis (GI tract)
Sjogren's syndrome (salivary glands, tear glands, joints)	Multiple sclerosis*
Goodpasture's syndrome (lungs, kidneys)	Addison's disease (adrenal)
Wegener's granulomatosis (blood vessels, sinuses, lungs, kidneys)	Primary biliary cirrhosis, Sclerosing cholangitis, Autoimmune hepatitis (liver)
Polymyalgia Rheumatica (large muscle groups)	Temporal Arteritis / Giant Cell Arteritis (arteries of the head and neck)
Guillain-Barre syndrome (nervous system)

The role of apoptosis in autoimmune thyroid disorders and thyroid cancer

Jen-Der Lin, professor of internal medicine.

Division of Endocrinology and Metabolism, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, 5 Fu-Shin Street, Kweishan County, Taoyuan Hsien, Taiwan, Republic of China

Apoptosis, or programmed cell death, is an active process of self destruction that requires the activation of a genetic programmethat may lead to changes in cell morphology, DNA fragmentation,and protein cross linking. Apoptosis can be triggered in severalways and involves many cellular functions. The mechanism providesprotection from the possible consequences of uncontrolled cellproliferation, which could lead to neoplasia. Cell death is afactor in the pathogenesis of several diseases, including autoimmunedisorders, cancer, AIDS, and neurodegenerative diseases. Regulationof apoptosis in cells undergoing proliferation may be the keyto reversing the natural progression of these disorders. Apoptosisinvolves the sequential activation of a series of caspases, whichare proteolytic enzymes that degrade a number of death substrates. Caspase is activated by two pathwaysthe mitochondrial pathwayand the death receptor pathwayand thereby may trigger nuclear enzymes to degrade chromosomal DNA and alter mitochondrial function.Specific pathways and non-specific signals (such as cytotoxicdrugs and radiation) may activate caspase. The most common ofthese pathways involves death receptors that have structures belongingto the tumour necrosis factor (TNF) receptor superfamily of proteins. Interaction of tumour necrosis factor with this receptor can inducecell death by the activation of various kinase enzymes that actas secondary messengers within the cell. Another member ofthis family, Fas antigen, and its ligand (FasL), are moleculesused by immune effector cells to kill targets.