Unit 6 - Hypersensitivity

Question 1

True or False:

TH2 response is anti-inflammatory

Answer 1

True

Question 2

True or False:

TH1 response is anti-inflammatory

Answer 2

False

- TH1 is PRO-inflammatory

Question 3

Define hypersensitivity

Answer 3

Exaggerated or inappropriate immune response causing inflammatory reactions and tissue damage

Question 4

What are the 4 types of hypersensitivities?

Answer 4

Type I
Type II
Type III
Type IV

Question 5

What are the immunoglobulins involved in a Type I hypersensitivity?

Answer 5

IgE

Question 6

What are the immunoglobulins involved in a Type II hypersensitivity?

Answer 6

IgM
IgG
Complement

Question 7

What are the immunoglobulins involved in a Type III hypersensitivity?

Answer 7

“Immune complex”
IgG
Complement

Question 8

What are the immunoglobulins involved in a Type IV hypersensitivity?

Answer 8

Ab-independent
T-cells!
- trick question ;)

Question 9

Which hypersensitivites are humoral? Which are cell-mediated?

Answer 9

Humoral = Type I, II, and III
Cell-mediated = IV

Question 10

Which type of hypersensitivity is considered an “allergy”?

Answer 10

Type I

Question 11

What are the two degress of severity of a type I hypersensitivity?

Answer 11

1. Atopy

2. Anaphylaxis

Question 12

What is atopy?

What are some examples (3)?

Answer 12

Inherited IgE-mediated allergies

• Hay fever (rhinitis)
• Asthma
• Atopic dermatitis

Question 13

What is anaphylaxis?

Answer 13

Systemic allergic response

• could lead to airway obstruction/circulatory collapse
• potentially lethal

Question 14

What % of the population is affected by atopic allergies?

Answer 14

10-30%

• it is significantly under-reported
• it’s “just a cold”

Question 15

Why is heredity a risk factor for a Type I HS?

Answer 15

There are genes that favour IgE production, mast cells, etc.

Question 16

True or False:

If a parent has a cat allergy, the child will also have a cat allergy

Answer 16

False

• allergies do NOT have to be the same
• only a chance that the child will have an allergy

Question 17

Why do IgE and allergy severity decrease with age?

Answer 17

B/c as you age, your immune system function declines

- IgE production will decrease

Question 18

True or False:

During agin, chronic allergy can result in irreversible airway damage

Answer 18

True

Question 19

Simply describe a Type II HS

Answer 19

Autoimmune response involving IgM, IgG or complement

Question 20

What are the three ways that a Type II HS can present?

Answer 20

1. Drug reactions
2. Molecuar mimicry
3. Idiopathic thrombocytopenia

Question 21

Explain what is happening in a Type II HS, with a drug reaction. What is the example used in class?

Answer 21

Penicillin

• penicillin binds to RBC surface proteins (hapten)
• immune response leads to complement leads to hemolysis
• Can lead to hemolytic ANEMIA

Question 22

Explain what is happening in a Type II HS, with molecular mimicry. What was the example used in class?

Answer 22

Streptococcus

• Antibodies against strep can lead to rheumatic fever
• Antibodies target cardiac proteins

Question 23

Explain what is happening in a Type II HS, with idiopathic thrombocytopenia.

Answer 23

Platelets are bound and killed by IgG

- we don’t know what causes it (hence, idiopathic)

Question 24

Simply describe a Type III HS

Answer 24

Antibody-antigen COMPLEXES bound together

Question 25

Describe the pathogensis of a Type III HS

Answer 25

1. Antibodies bind with antigen and form complexes 2. Large complexes are removed by phagocytes 3. Small complexes deposit in microvasculature (like the glomerulus) 4. Binds with complement, attracts proinflammatory basophils and neutrophils = local inflammation and tissue damage

Question 26

During a Type III HS, what are the two types of leukocytes that are attracted by the binding of complement? What do they do?

Answer 26

1. Basophils - cause vasodilation 2. Neutrophils - release enzymes that cause blood vessel damage

Question 27

What are three examples of Type III HSs?

Answer 27

1. Serum sickness - form complexes against the foreign serum 2. Systemic Lupus Erythematosus - complexes collect in microvasculature 3. Rheumatoid Arthritis - antibody-antigen COMPLEXES deposit between joints

Question 28

True or False: | Rheumatoid Arthritis can be either a Type III or a Type IV HS

Answer 28

TRUE! 1. Antibody-antigen complexes deposit between the joints OR 2. T-cells target synovial membrane (soft tissue) between the joints

Question 29

Simply define a Type Iv HS

Answer 29

T-cell specific autoimmune response

Question 30

True or False: | A Type IV HS has a delayed response

Answer 30

True | - usually 24 - 72 hours