Autoimmunity & disorders ppt by DR.C P. PRINCE

PPT prepared by :
DR.PRINCE C P
HOD & Associate Professor
Department of Microbiology,
Mother Theresa
Post Graduate & Research Institute of Health Sciences (Government of Puducherry Institution)
Pondicherry.
An autoimmune disorder is a condition that occurs when the immune system attacks and destroys healthy body tissue.
Graves’ disease
Hashimoto’s thyroiditis
Addison’s disease
Myasthenia gravis
SLE
Diabetes mellitus type

1. Autoimmunity DR.PRINCE C P HOD & Associate Professor Department of Microbiology, Mother Theresa Post Graduate & Research Institute of Health Sciences (Government of Puducherry Institution) Pondicherry

2. Autoimmunity Autoimmunity is defined as the presence of immune response of auto Antibody against self Antigen. It can be a humoral or cell mediated immune response against the constituents of the body’s own tissues.

3. Autoimmune disorder An autoimmune disorder is a condition that occurs when the immune system attacks and destroys healthy body tissue

4. Autoimmunity Graves’ disease Hashimoto’s thyroiditis Addison’s disease Myasthenia gravis SLE Diabetes mellitus type 1

5. Auto or self antigens Are antigens that presents in ones own cells Are altered by the action of bacteria, viruses, chemicals or other drugs Auto antibodies Altered cell (Auto Ag) - elicits the productions of Antibody

6. Causes of autoimmune diseases 1. Sequestered or Hidden antigens Ag in the secluded places - are not accessible to the immune system. E.g. Lens Ag, Sperm Ag, etc. 2. Neo antigens Altered or Modified Antigens – by physical (irradiation), chemical (drugs) or microbial agents ( intracellular viruses) 3. Cessation of Tolerance It may result when tolerance to the self-Ag is abrogated.

7. Causes of autoimmune diseases 4. Cross reacting Antigens A foreign Ag which resembles self a 2nd Ag Many species share organ specific Ags . E.g. Ag of Human brain & Ag of sheep brain, Streptococcal M protein & Heart muscles, Nephritogenic strains of Streptococci Ags & Renal glomeruli shares similar epiotes . 5. Loss of Immunoregulation Loss of Self tolerance - caused by over activity or lowered activity of T and B- cells 6. Genetic

8. Classification of autoimmune disorders 1. Haemolytic autoimmune diseases 2. Localised autoimmune diseases 3. Systemic autoimmune diseases

9. Myasthenia Gravis • 80 to 90% of patients have Autoantibodies against acetylcholine receptor • Combination of the Abs to the receptors blocks the binding of acetylcholine which destroy the receptors • Muscle weakness • Repetitive movements very difficult! • In particular eye bulb muscles affected • Life threatening when muscles for respiration are affected • Can be transferred to foetus . • Abs can be detected with RIA methods Anti-cholinesterase agents are employed in therapy

10. Grave’s Disease • Autoantibodies against receptor for thyroid stimulating hormone (TSH) • Activate receptor leading to excessive thyroid hormone production • Women are more susceptible than men by a margin of 7:1 and usually present between the ages of 30 and 40.

11. Systemic Lupus Erythematosus It is a chronic systemic inflammatory disease marked by alternating exacerbation and remissions Approximately 1 in every 2000 individuals are affected Age of onset is usually b/w 20 and 40 yrs of age Women are much more likely than men to be stricken by a margin of 13 to 1 Etiology is unknown but may be due to genetic and environmental factors Auto-antibodies against nuclearcomponents (DNA, histones,ribosomes , snRNP , etc) Local inflammation in skin, joints and kidneys, multi-organ damage

12. Laboratory Diagnosis of SLE: A screening test for antinuclear antibody (ANA) is usually the first test done Double-stranded DNA ( ds -DNA): These Abs are the most specific for SLE and are seen only in patients with SLE Antihistone antibody: Histone is a major component of chromatin, This antibody is found in lupus patients Anti- Sm antibody: Antibody to extractable nuclear antigen was first described in a patient named Smith hence it is called anti- Sm

13. Rheumatoid Arthritis Rheumatoid arthritis is a systemic autoimmune disorder It involves the synovial membrane of multiple joints Women are more likely to be affected than men and usually strikes between the ages of 20 and 40 The main immunologic finding is the presence of RF RF is a 19S Ab directed against the Fc portion of IgG (Rheumatoid Factor/RA factor)

14. Rheumatoid Arthritis

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