Hypersensitivity and Autoimmunity

Question 1

What is type 1 hypersensitivity?

Answer 1

• When the body recognises an environmental antigen as a pathogen

Question 2

What does type 1 hypersensitivity release?

Answer 2

IgE

Question 3

What cells are triggered by type 1 hypersensitivity?

Answer 3

• Mast cells

- Blood basophils

Question 4

What happens during sensitisation?

Answer 4

• The allergen is shown to a T helper cell by an APC

- B cells then differentiate

Question 5

What do B cells produce during sensitisation?

Answer 5

IgE

Question 6

What occurs if the patient is exposed to the antigen after sensitisation?

Answer 6

• Mast cells release cytokines

- Allergic reaction results

Question 7

What is type 2 hypersensitivity?

Answer 7

Body’s antibodies bind to antigens on its own cells

Question 8

What can happen if penicillin binds to blood cell?

Answer 8

Antibodies are produced in response to the antigens on that cells surface

Question 9

What can IgG and IgM antibodies trigger?

Answer 9

Complement system

Question 10

What does the activation of the complement system cause?

Answer 10

Lysis

Question 11

What is type 3 hypersensitivity?

Answer 11

When the body forms immune complexes

Question 12

What are immune complexes?

Answer 12

When antibodies stick together in a clump

Question 13

With regards to concentration, how do immune complexes form?

Answer 13

• Low conc. of antibody

- High conc. of antigen

Question 14

What causes type 4 hypersensitivity?

Answer 14

CD4 helper T cells recognise a foreign antigen

Question 15

What do these CD4 helper T cells release?

Answer 15

Cytokines

Question 16

What does the release of these cytokines cause?

Answer 16

Inflammatory response

Question 17

How fast does the early phase response react?

Answer 17

Within minutes

Question 18

What is released during the early phase response?

Answer 18

• Histamine
• Heparin
• Chemotactic factors

Question 19

What cell releases the chemicals in the early phase response?

Answer 19

Mast cell mediators

Question 20

What is released during the late phase response?

Answer 20

• Prostaglandins

- Leukotrines

Question 21

What cytokines are released in the late phase response?

Answer 21

Th2 cytokines

Question 22

What cells are the mediators of the late phase response?

Answer 22

Eosinophils

Question 23

What 2 complexes can form during type 3 hypersensitivity?

Answer 23

• Localised

- Systemic

Question 24

What is localised type 3 complexes and how is it cleared?

Answer 24

• Inflammation of nearby tissue

- Cleared by macrophages

Question 25

What is an autoimmune disease?

Answer 25

Disorder caused by organ damage of the immune system targeting self antigens

Question 26

What 5 factors can result in an autoimmune disease?

Answer 26

- Genetic factors - Immune regulatory factors - Hormonal factors - Environmental factors - Other

Question 27

What are the pathogenic mechanisms of autoimmune disease?

Answer 27

- Cell mediated - Antibody mediated - Antibody + compliment - Immune complex mediated - Accumulation of innate compounds

Question 28

Name 3 autoimmune thyroid diseases

Answer 28

- Hashimoto's thyroiditis - Thyroxicosis - Primary myxoedema

Question 29

Name an autoimmune stomach disease

Answer 29

Pernicious anaemia

Question 30

Name an autoimmune adrenal disease

Answer 30

Addisons disease

Question 31

Name an autoimmune disease that damages the muscle

Answer 31

Dermatomyositis

Question 32

Name an autoimmune disease that affects the skin

Answer 32

Scleroderma

Question 33

Name and autoimmune disease that affects the kidneys

Answer 33

SLE (lupus)

Question 34

Name an autoimmune disease of the joints

Answer 34

Rheumatoid arthritis