Lecture 4

Question 1

Define extrinsic asthma

Answer 1

Atopic ‘allergic’, young onset, hyper responsive

Question 2

Define intrinsic asthma

Answer 2

Non atopic, non allergic, middle aged, hyper responsive, more severe airflow limitation

Question 3

Define anaphylaxis

Answer 3

Acute severe allergic reaction resulting in respiratory collapse

Question 4

Define allergy

Answer 4

Changed reactivity

Question 5

What is an allergy driven by?

Answer 5

T helper lymphocyte subset (Th2 cells) and their products (Th2 cytokines)

Question 6

Name the cytokines that Th1 produce

Answer 6

Interferon gamma and IL-12

Question 7

Name the cytokines that Th2 produce

Answer 7

Il-4, Il-3 and il-13, il-5, il-9

Question 8

In normal airways do th1 or th2 dominate

Answer 8

Th1

Question 9

What factors favour the th1 phenotype

Answer 9

Present of older siblings
Early exposure to day care
TB, measles, hep A infection
Rural environment

Question 10

What factors favour the th2 phenotype

Answer 10

Widespread use of antibiotics, western lifestyle, urban environment, diet, sensitisation to house dust mites and cockroaches

Question 11

What do the T cells do during allergic response

Answer 11

Il-4 and il-13 switch B lymphocytes to make igE antibody. IgE fixes onto the surface if mast cells (sensitisation phase) - process takes a month to occur

Question 12

What is igE?

Answer 12

Relatively rare immunoglobulin in plasma if you are allergic it will be present in higher numbers

Question 13

How many asthma cases are not allergic?

Answer 13

30%

Question 14

What is the sensitisation phase?

Answer 14

Antibodies are present on to the surface of of mast cells this process takes ages to occur

Question 15

What causes degranulation?

Answer 15

Cross linking igE bound to Fc£R1 on the mast cell

Question 16

What’s triggers mast deck release and degranulation?

Answer 16

Re-exposure

Question 17

Name the granule products

Answer 17

Histamine, TNF and other cytokines, proteases and heparins

Question 18

Does the skin have high or low leeks of histamine

Answer 18

High histamine

Question 19

Does the lung have high or low histamine levels

Answer 19

Low histamine

Question 20

Name two membrane derived lipid mediators of inflammation

Answer 20

Leukotrienes and prostaglandins

Question 21

What is the role of eosinophils in allergy?

Answer 21

Release basic proteins and ROS - responsible for getting rid of the pathogens and microorganisms, they can also damage the airways in the body or the skin in the body

Question 22

What do eosinophils produce?

Answer 22

Produce cytokines, leukotrienes, and prostaglandins

Question 23

Name some H1 receptor antagonists

Answer 23

Chlorpheniramine, astemizole, cetrizine

Question 24

What are H1 receptor antagonists effective in treating?

Answer 24

Allergic rhinitis, urticaria - not effective in asthma as the mast cells in the lungs do not have high levels of histamine

Question 25

What are chromones?

Answer 25

Mast cell stabilisers - inhibit mediator release from lung mast cells so mast cells are unable to granulate

Question 26

What are chromones effective for?

Answer 26

Early or late phase asthma

Question 27

Mode of action of disodium cromoglycate and nedocromil

Answer 27

Inhibit eosinophils chemotaxis
Inhibit sensory nerve fibre excitation and neural reflex - inhibit NKA, BK SO2
- induced bronhcocontriction