L19-20 - Autoimmunity

Question 1

What is autoimmunity?

Answer 1

Immune response against a self antigen

Question 2

What is an autoantigen?

Answer 2

Any self protein that can trigger an immune response

Question 3

What is autoimmune disease?

Answer 3

A build up of pathological changes resulting from an autoimmune response

Question 4

What are the specific (2) and main non-specific (3) effector mechanisms of autoimmune damage?

Answer 4

Specific - antibodies, T cells

Non-specific - complement, phagocytes, NK cells

Question 5

What are organ specific autoimmune diseases?

Give 2 examples

Answer 5

Damage is confined to the organ targeted in the immune response

Myasthenia gravis, Grave’s disease, T1 diabetes, autoimmune haemolytic anaemias

Question 6

What are systemic autoimmune diseases?

Give 2 examples

Answer 6

Immune response against antigens associated with multiple tissue types

Rheumatoid arthritis, rheumatic fever, systemic lupus erythematosus, reiter’s syndrome

Question 7

What are the 3 general causes of autoimmune disease?

Answer 7

Genetics, environmental factors, errors in immune regulation

Question 8

What gene complex is most commonly associated with autoimmunity? What specifically is it associated with?

Answer 8

HLA complex (includes MHC genes)

The control of and susceptibility to autoimmune disease

Question 9

What environmental triggers can result in autoimmune disease?

Answer 9

Pathogens, drugs/toxins, hormones

Question 10

How do hormones affect autoimmune disease susceptibility?

Answer 10

Females more at risk due to oestrogen levels

Young - high oestrogen stimulates B related autoimmunity
Older - low oestrogen stimulates T related autoimmunity

Question 11

How is autoimmunity involved in pregnancy?

Answer 11

• Rising hormones can cause abortion

- Endometriosis and preeclampsia thought to be autoimmune

Question 12

What can complement deficiencies result in in terms of autoimmune disease?

Answer 12

CD59 and 55 deficiencies - autoimmune haemolytic anaemia

Classical pathway deficiencies - systemic lupus, rheumatoid arthritis

Question 13

What is Myasthenia gravis?

Answer 13

Neuromuscular disorder with progressive weakness and loss of muscle control

Question 14

What is the pathogenesis of Myasthenia gravis?

Answer 14

Autoantibodies against acetylcholine receptors (involved in muscle contraction)

Question 15

What is the pathogenesis of Grave’s disease?

Answer 15

Autoantibodies mimic TSH and bind to TSH receptors

This increases thyroid hormone production, producing hyperthyroidism

Question 16

What are the treatment options for Grave’s disease?

Answer 16

Ease symptoms (anxiety, high HR, sweating) with beta-blockers

Treat hyperthyroidism with anti-thyroid medication, radioactive iodine or surgery

Question 17

What is the pathology of insulin-dependent diabetes mellitus?

Answer 17

T cell mediated autoimmunity destroys pancreatic beta cells

Reduces insulin output

Question 18

What is the pathogenesis of rheumatoid arthritis?

Answer 18

• IgM, G and A against IgG Fc regions produced

- Immune complexes congregate in joint synovium, so reaction results in inflamed joints

Question 19

What is the pathogenesis of rheumatic fever?

Answer 19

• Body produces antibodies against Streptococcus pyogenes during infection
• These cross-react with heart tissue

Question 20

What is systemic lupus erythematosus (SLE)? What is its pathology?

Answer 20

Widespread tissue damage and inflammation

Autoantibodies created against cell nuclei, dsDNA, nucleoproteins, and cytoplasmic proteins (related to T and B cell hyperactivity)

Question 21

How is systemic lupus erythematosus (SLE) treated?

Answer 21

Medication to ease symptoms as there is no cure:

• Anti-inflammatories for sore joints
• Steroid creams for rashes
• Corticosteroids for general inflammation

Question 22

What is Reiter’s syndrome?

Answer 22

Reactive arthritis in response to infection

Question 23

What are the signs of Reiter’s syndrome?

Answer 23

Joint inflammation (especially knees and ankles), inflammation of the eyes and urinary tract, hard nodules on the feet

Question 24

What is the cause of Reiter’s syndrome?

Answer 24

Bacterial infection in the intestines, urinary tract, or genitals

E.g. STIs, Salmonella, Shigella

Question 25

What are some general ways to diagnose autoimmune diseases?

Answer 25

CRP, autoantibody titres, rheumatoid factor presence

Question 26

How is T1 diabetes diagnosed?

Answer 26

Fasting glucose test

Question 27

What are the general treatment options for autoimmune disease?
(6)

Answer 27

• Anti-inflammatories (corticosteroids)
• Immunosupressants (e.g. methotrexate)
• Cell blocking reagents (e.g. aCD20, aCD3)
• Cytokine blocking reagents (e.g. TNF)
• Radiation
• Plasmaphoresis