jueves, 25 de octubre de 2018

What is Autoimmune Disease?

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By Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Cantab)

Like all other animals in the animal kingdom, humans also possess an immune system. The main functions of the immune system are to defend the body from germs and other foreign invaders.

The immune system is composed of special cells and organs that deal with invaders and allergens. The cells create antibodies to fight off the infection or foreign intruders.

To defend the body the immunity must recognise what is self or what belongs to the body and what is non-self or foreign to the body.

Autoimmune disorders occur when the body fails to tell the difference between self and non-self. When this happens, the body makes antibodies that are directed towards the body’s own tissues. These are called auto-antibodies. The autoantibodies attack the normal cells by mistake.

Regulatory T cells

One of the components of the immune system is the regulatory T cells. These help regulate the immune system.

When autoimmune disorders occur, these regulatory T cells fail in their function. This results in damage to various organs and tissues that are termed autoimmune disease.

The type of autoimmune disorder depends on the type of body tissue that is affected. There are more than 80 known types of autoimmune disorders.

Autoimmune disorder statistics

Autoimmune diseases affect various organs and organ systems. In the United States at least 23.5 million are affected by some form of autoimmune disorders.

These disorders are one of the leading causes of death and disability. While some of these disorders are rare, some like Hashimoto’s thyroiditis are quite common.

Risk factors

Some people are at a greater risk of getting autoimmune disorders. These include women of child bearing age.

In general most of the autoimmune disorders affect women more commonly than men. The conditions often begin during the reproductive period of a woman’s life.

Those who have a family history of the condition are also more likely get the disease. For example, lupus and multiple sclerosis runs in families.

Some races and ethnicities also have a greater risk. For example type 1 diabetes is more common in white people and lupus is more severe for African-American and those of Hispanic origin.

Genetics may play a role in causation of autoimmune disorders but several environmental factors may also be important in causing autoimmune disorders. These include exposure to solvents, chemicals, viral and bacterial infections, sunlight etc.

Diagnosis and treatment of autoimmune disorders

There are several different tests to detect autoimmune disorders. These may be specific for the type of the disorder.

Depending on the type of the disorder, these conditions are treated by a wide variety of specialists. For example:-

a nephrologist may treat lupus affected kidneys
a neurologist or nerve and brain disease specialist may treat multiple sclerosis and myasthenia gravis
a rheumatologist may treat arthritis and other rheumatic diseases, such as scleroderma and rheumatoid arthritis
an endocrinologist or hormone disorders specialist may treat disorders like diabetes (type 1) and thyropiditis (Hashimoto’s thyroiditis)
a skin doctor or dermatologist treats diseases such as psoriasis and lupus
a blood disease specialist or haematologist treats anemias related to autoimmune disorders
a gastroenterologist treats inflammatory bowel disease

There are many types of medicines that may be used in specific types of autoimmune disorders. While some treatments aim at relieving symptoms like pain and inflammation, others target the disease process.

Some autoimmune diseases like thyroiditis and diabetes make the manufacture of vital components difficult. For example in diabetes, there is lack of production of insulin. This hormone thus needs to be substituted from outside.

Thyroid hormone replacement similarly restores thyroid hormone levels in those with underactive thyroids.

Corticosteroids are used to suppress the immune system and prevent the exaggerated response. Other agents like anti-TNF medications also block the inflammation and are used in autoimmune arthritis and psoriasis.

There are several lifestyle changes that may be adopted along with treatment of autoimmune disorders. These include eating a healthy and balanced diet, getting regular physical activity, maintaining a healthy body weight, getting adequate rest, reducing stress etc.