Auto-Immunity Flashcards
What is autoimmunity?
Immune response against the host due to loss of immunological tolerance to self antigens.
What is autoimmune disease?
Disease caused by tissue damage due to autoimmune response.
What are the two categories?
Organ specific - antigens within specific organ/tissue
Non-organ specific - antigens throughout the body
Give some examples of organ specific diseases.
Thyroid - hashimoto's, graves', addison's Pancreas - T1DM Myasthenia gravis MS Goodpastures
Give some examples of non-specific diseases.
Autoimmune haemolytic anaemia.
Rheumatoid arthritis
SLE
How does autoimmunity cause disease?
Complement activation
Antibody mediated cell cytotoxicity
Neutrophil activation
Cytotoxic T cells
What 2 things must be considered in autoimmune serology?
Sensitivity - how many who have disease will have auto-antibody.
Specificity
How are antibodies transferred to the foetus?
IgG in T3
If mum has auto-immune disease, will the baby?
Possibly.
Varying risk with each condition.
Graves - 10%
What triggers autoimmunity?
Genetic Factors
Environmental Factors - hormones, infections, drugs
What infection is characterised by an immune reaction against antigen in cardiac muscle?
Rheumatic fevere
Strep pyogenes - M protein
Which other diseases can be caused by infection?
Guillain-Barre syndrome
Diabetes type 1
What treatment can be used against auto-immune conditions?
Plasmapheresis Immunosuppression Anti-inflammatory drugs Replacement therapy Surgery Monoclonal antibodies
What are monoclonal antibodies?
Antibodies which all bind to the same epitope on an antigen.
What is the criteria for diagnosing autoimmune disease (6)?
- Presence of auto-antibodies/autoreactive T cells
- Levels of antibodies correlate with disease severity
- Autoantibodies/autoreactive T cells found at site of tissue damage
- Transfer of auto-antibody or autoreactive T cell to healthy host induces autoimmune disease
- Clinical benefit from immunomodulatory therapy
- Family History
Give three examples where IgG transfer from mother to fetes can cause autoimmune disease in newborn?
Graves - TSH receptor antibody
Haemolytic anaemia - RBC antibody - lysis
Thrombocytopenia - platelet antibody -lysis
What is an example of an infection induce autoimmune disease?
Strep progenes causes rheumatic fever.
M protein has similar structure to heart muscle antigen. Antibodies cross-react and damage the heart - valves.
List symptoms of Graves’ disease.
Exophthalmos Goitre Tachycardia and palpitations Sweating Tremor Nausea and diarrhoea Oligomenorrhea Weight loss
What is the treatment for Graves’ disease?
Carbimazole - inhibits thyroid peroxidase
Radioactive iodine
Surgery - thyroidectomy
Name two autoantibodies in Hashimoto’s disease.
Anti-thyroglobulin
Anti-thyroid peroxidase
What type of reaction is Hashimoto’s?
Type IV - delayed
What are symptoms of Hashimoto’s?
Weight gain Fatigue Hair loss Anxiety Dry skin Infertility
What is a biopsy of the thyroid likely to show in Hashimoto’s disease?
Infiltrate of lymphocytes - CD4 and CD8
Plasma cells
What is the treatment for hashimoto’s?
Replacement therapy with thyroxine
