L21: Allergy And Allergic Disease

Question 1

What is hypersensitivity

Answer 1

The reaction of the immune system that is detrimental to the host
We can have a normal immune response triggered and persistent in absence of pathogen
OR
Have an inappropriate exaggerated immune response to an agent

Question 2

How many types of hypersensitivity is there

Answer 2

Type 1
Type 2
Type 3
Type 4

Question 3

What it type 1 hypersensitivity

Answer 3

IgE mediated that causes mast cell degranulation and activated eosinophils

Question 4

What is type 2 hypersensitivity

Answer 4

Self igG against own self antigen

Question 5

What is type 3 hypersensitivity

Answer 5

IgG complex in with circulating antigen that causes damage by activation the immune system

Question 6

What is type 4 hypersensitivity

Answer 6

Mediated but T cells and is delayed hypersensitivity

Question 7

What type of hypersensitivity does anaphyalaxis have

Answer 7

Type 1

Question 8

What type of hypersensitivity does autoimmune disease have

Answer 8

Type2

Question 9

What type of hypersensitivity does glomerulonephritis have

Answer 9

Type 3

Question 10

What type of hypersensitivity does contact dermatitis have

Answer 10

Type 4

Question 11

What are the clinical features of a type 1 hypersensitivity

Answer 11

Very early onset

Life threatening

Question 12

What are the clinical features of a type 4 hypersensitivity

Answer 12

Grater than 4 hours often 2days
Usually a skin reaction
Takes weeks to settle down
Not life threatening

Question 13

How can you test for type 4 hypersensitivity

Answer 13

Patch testing

Question 14

After how many days do you look for redness with a patch test

Answer 14

5 days

Question 15

Which 3 things are not allergy reactions

Answer 15

Irritant response
Food intolerance
Side effect of a drug

Question 16

How do we diagnose type 1 hypersensitivity

Answer 16

Look for specific IGE in the blood
Or
Skin prick testing

Question 17

What would the ige in the blood show for someone who has an allergy

Answer 17

Ige consistent with ige mediated reaction

Question 18

Can you get a type 1 hypersensitivity on your first exposure to an antigen

Answer 18

No

Question 19

How do we develop a type 1 hypersensitivity

Answer 19

1) exposed to an allergen
2) sensitised to produce IGE
3) reexposure you get an allergic response

Question 20

What is the normal level of IgE like in the serum

Answer 20

Lowest immunoglobulin

Question 21

On which cell is an IgE found

Answer 21

On mast cells

Question 22

When there is an allergy what happens to Ige and mast cells

Answer 22

1) allergy is detected by IGE and binds to the allergen
2) Ige binds to FceR1 receptors on the mas cell
3) the mast cell is activated and releases substances that cause an allergic symptom

Question 23

What are the early phase mediators released from mast cells

Answer 23

Histamine
Kallikreins
Serotonin
Proteases

Question 24

What are the late phase mast cell mediators

Answer 24

Prostaglandins
Leukotrienes
Cytokines

Question 25

Overall what does the mast cell mediators produce

Answer 25

``` Vasodilation Increased vascular permeability Irritates nerve endings Increased heart rate Bronchoconstriction Glandular secretion ```

Question 26

Is anaphlayaxis severe or a normal disease

Answer 26

Severe life threatening disease

Question 27

What is the treatment for anaphylaxis

Answer 27

Intramuscular adrenaline Steroids Antihistamines- to prevent late phase responce

Question 28

What type of receptor does all allergy effector cells express

Answer 28

FceR’s

Question 29

What are the allergy effector cells

Answer 29

Mast cells Basophils Eosinophils

Question 30

What are basophils also known as

Answer 30

Circulating mast cells

Question 31

Where are mast cells found

Answer 31

Inside tissue

Question 32

What do basophils release

Answer 32

Histamine IL4 IL13

Question 33

Name examples of type 1 IgE mediated allergy

Answer 33

``` Hay fever Allergic asthma Atopic dermatitis Food allergy Drug allergy Latex allergy Venom allergy ```

Question 34

What are the 2 reasons we get allergy

Answer 34

Genetic | Environment

Question 35

What is the hygiene hypothesis

Answer 35

Lack of exposure to germs in early life so our immune system goes away from TH1 to TH2 phenotype

Question 36

Which cell recognises helminth parasite

Answer 36

Mast cells

Question 37

What does the hygiene hypothesis conclude as

Answer 37

Children that are less exposed to germs are likely to develop allergic reactions

Question 38

Which cells kill helminth parasites

Answer 38

Eosinophils

Question 39

How do eosinophils kill helminth parasites

Answer 39

IgE binds to helminth Eosinophils binds to IGE via FCER1 Eosinophils kill by toxic lysosomal granules that kill the helminth parasite

Question 40

How do we get rid of dead helminth parasite that is killed by eosinophils

Answer 40

Il3 from effector cells cause goblet cells to produce mucus In the lungs we get bronchoconstriction Contraction of smooth muscles in the gut

Question 41

What does sensitisation mean

Answer 41

When the immune system recognises an allergen but does not necessarily induce systemic symptoms

Question 42

What is anaphylactoid

Answer 42

A systemic reaction that is not IGE mediated but can be severe and life threatening