Autoimmune Diseases

Auto immune diseases are those diseases which are caused due to altered immune response of the body against itself.

Normally the human body recognizes its own cells and does not pose a problem for them. But in these Auto immune diseases the body fails to recognize its own cells and unleashes an antigen antibody reaction against its own cells.

Types:

There are two major types of Auto immune diseases. One of the types is an organ specific antigen antibody reaction. The other one is non organ specific antigen antibody reaction.

Causes:

The exact cause remains to be found out. Yet there is a definite genetic factor involved. Auto immune responses can either occur spontaneously without any prior stimulus in a genetically predisposed individual. Or the Auto immune response may follow the occurrence of some acute illness, usually a virus infection, but again it does so only in genetically predisposed individuals.

Common Auto immune disease:

Organ specific

Hashimoto's thyroiditis.

Primary myxedema

Thyrotoxicosis

Pernicious anemia

Auto immune Addison's disease

Type I Diabetes Mellitus

Good pasteur's syndrome

Myasthenia gravis

Sympathetic opthalmia

Auto immune hemolytic anemia

Idiopathic thrombocytopenic purpura

Primary biliary cirrhosis

Chronic active hepatitis

Sjogren's syndrome

Non-organ specific

Rheumatoid arthritis

Dermato myositis

Systemic sclerosis

Systemic Lupus erythematosus (SLE)

Mechanisms of Auto immune diseases:

There is some relation of the Auto immune response with the advancing age, because it is usually found in people with advanced age. Though it has not yet been proved, but there is a suggestion or a theory put forward that with advancing age, the Ts cells or the suppressor cells lose their control over the Th cells or the T helper cells.

Sequestrated antigen:

There are certain antigens which remain isolated all through the human life, and hence do not have any chance to develop contact with the normal immunological system, and hence the body does not get a chance to develop self recognition.The best example is of human sperm. It remains inside the vas deferens and if in case it spills out into the surrounding tissue, can excite an Auto immune response.

Infection:

The infections are caused by micro organisms and they also have certain antigens in their system. These antigens can cross react with the antigen of the tissue in the humans. For example the streptococci has a similar antigen as that of the human heart, hence the when the body starts an immune response or attack on the streptococcal antigen; it also affects the muscles of the heart in the human body.

Drugs:

Certain drugs like methyldopa used in treatment, can trigger an Auto immune response.

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