Autoimmunity: Immune response against self-tissue of the body.
If this response cause Organ damage it leads to Autoimmune diseases.
Pathology: Autoimmunity develops due to the failure of immunological tolerance.
Normally there are two types of tolerance mechanisms in our body.
1. Central tolerance occurs during lymphocyte development; In this Elimination of T and B Lymphocytes that recognize self-antigens, before they develop into mature cells. Failure of this process leads to release of these autoreactive cells into peripheral tissues.
2. Peripheral tolerance mechanism controlled by T-cells which destroy these autoreactive cells by apoptosis.
However, sometimes these two tolerance mechanisms fail leads to autoimmunity.
Generally, 1 in 30 adults has this autoimmunity. If this is sufficient to cause damage to tissue or organ can result in autoimmune disorder.
Factors that cause autoimmunity.
Still not clear about the factors that lead to autoimmunity. According to some theories following may be some factors:
1. Infections: Due to the cross-reaction between infectious pathogen and self-antigens.
2. Hormone levels.
3. Genetic predisposition
4. Cigarette smoking
5. Junk food.
6. Side effects of drug treatment: This occurs occasionally. For example metabolic products of halothane bind to liver enzymes resulting in structurally new protein. This recognized as a foreign antigen by body leads to hepatic necrosis.
7. Hygiene hypothesis: This states that children today are not exposed to many germs due to inventing of antiseptics and vaccines. This lack of exposure could make their immune system overact to harmless substances.
Common Autoimmune diseases:
Organ-specific:(Immune response directed against localized antigens)
1. Graves disease.
2. Hashimoto’s thyroiditis.
3. Type – I Diabetes Mellitus.
4. Pernicious anaemia.
5. Addisons disease
6. Pemphigus Vulgaris.
7. Autoimmune haemolytic anaemia
8. Idiopathic thrombocytopenic purpura.
9. Rheumatoid arthritis.
10. Myasthenia Gravis.
11. Autoimmune hepatitis
12. Sjogren’s syndrome
Multisystem (Immune response directed to widespread target antigens)
1. Systemic sclerosis.
2. Systemic Lupus erythematosus.
Numbness and tingling in the hands and feet
Swelling and redness
Although these are general symptoms, each disease may have specific symptoms.
Tests for Autoantibodies:
Anti-citrullinated peptide antibodies
Treatment depends on specific autoimmune diseases.