Allergy As A Drug Target

Question 1

Allergy define

Answer 1

Adaptive immune response to an allergen
A hypersensitivity reaction initiated by immunological mechanisms

Question 2

Sensitivity define

Answer 2

When an individual has an exaggerated response to the normal effects of a substance

Question 3

Intolerance define

Answer 3

When a substance causes unpleasant symptoms such as diarrhoea
Doesn’t involve the immune system

Question 4

4 types of hypersensitivity reactions and antibodies involved

Answer 4

Type 1 involves IgE antibody against soluble antigen
Type 2- involves iGg and IgM antibodies
Type 3- involves interactions of IgG, IgM and occasionally IgA to form immune complexes
Type 4- T-cell mediated reactions that can involve tissue damage

Question 5

Symptom define

Answer 5

Something the individual reports to feel/experience
Subjective

Question 6

Sign define

Answer 6

Physical manifestation of the disease that can be observed
Objective

Question 7

Type 1 hypersensitivity + example

Answer 7

Involve IgE antibody against soluble antigen, triggering mast cell degranulation
E.g anaphylactic response to peanut butter , asthma

Question 8

Type 2 hypersensitivity + example

Answer 8

Involes IgG and IgM antibodies directed against cellular antigens, leading to cytotoxicity mediated by other immune system effectors
E.g haemolytic transfusion reaction when rbcs destroyed due to mismatch in blood types

Question 9

Type 3 hypersensitivity + example

Answer 9

Involves interaction of IgG, IgM and occasionally IgS antibodies with antigens to form immune complexes
Accumulation of immune complexes in tissue leads to tissue damage mediated by other immune system effectors
E.g post streptococcus glomerulonephritis

Question 10

Type 4 hypersensitivity + example

Answer 10

T-cell mediated reactions that can involve tissue damage mediated by activated macrophages and cytotoxic T cells
This is a delayed hypersensitivity reaction (up to 72 hours after exposure to antigen)
E.g T1 diabetes, coeliac disease , MS

Question 11

Difference in hypersensitivity reactions

Answer 11

Type 1-3 are B cell/ antibody related, while type 4 is cell mediated

Question 12

Atrophy

Answer 12

Tendency to develop allergic responses

Question 13

% of population atopic?

Answer 13

20% to 30%

Question 14

Side effect

Answer 14

Isn’t necessarily immune mediated and may be common and predictable

Question 15

Allergy test

Answer 15

Histamine testing
Serum specific IgE
Serum mast cell tyrptase levels

Question 16

Manage mild allergy : not life threatening

Answer 16

Sedating antihistamine: chlorophenamine
Non-sedating : loratidine

Avoid allergen

Question 17

Signs of anaphylaxis

Answer 17

Skin- hives,itching, swelling of lips,tongue,face
Airway- tightness, trouble breathing ,wheezing
CNS- anxiety, headache,dizziness
Cardiovascular system- chest pain, low bp, rapid HR
GI Tract- nausea, vomiting ,abdominal cramping

Question 18

Anaphylaxis management

Answer 18

Give IM (intramuscular) adrenaline

Question 19

Why give adrenaline for anaphylaxis?

Answer 19

Alpha 1-sm contraction
Alpha 2- inhibition of transmitter release +sm contraction
Beta- heart muscle contraction, sm relaxation