Unit 6 - Hypersensitivity Flashcards
True or False:
TH2 response is anti-inflammatory
True
True or False:
TH1 response is anti-inflammatory
False
- TH1 is PRO-inflammatory
Define hypersensitivity
Exaggerated or inappropriate immune response causing inflammatory reactions and tissue damage
What are the 4 types of hypersensitivities?
Type I
Type II
Type III
Type IV
What are the immunoglobulins involved in a Type I hypersensitivity?
IgE
What are the immunoglobulins involved in a Type II hypersensitivity?
IgM
IgG
Complement
What are the immunoglobulins involved in a Type III hypersensitivity?
“Immune complex”
IgG
Complement
What are the immunoglobulins involved in a Type IV hypersensitivity?
Ab-independent
T-cells!
- trick question ;)
Which hypersensitivites are humoral? Which are cell-mediated?
Humoral = Type I, II, and III Cell-mediated = IV
Which type of hypersensitivity is considered an “allergy”?
Type I
What are the two degress of severity of a type I hypersensitivity?
- Atopy
2. Anaphylaxis
What is atopy?
What are some examples (3)?
Inherited IgE-mediated allergies
- Hay fever (rhinitis)
- Asthma
- Atopic dermatitis
What is anaphylaxis?
Systemic allergic response
- could lead to airway obstruction/circulatory collapse
- potentially lethal
What % of the population is affected by atopic allergies?
10-30%
- it is significantly under-reported
- it’s “just a cold”
Why is heredity a risk factor for a Type I HS?
There are genes that favour IgE production, mast cells, etc.
True or False:
If a parent has a cat allergy, the child will also have a cat allergy
False
- allergies do NOT have to be the same
- only a chance that the child will have an allergy
Why do IgE and allergy severity decrease with age?
B/c as you age, your immune system function declines
- IgE production will decrease
True or False:
During agin, chronic allergy can result in irreversible airway damage
True
Simply describe a Type II HS
Autoimmune response involving IgM, IgG or complement
What are the three ways that a Type II HS can present?
- Drug reactions
- Molecuar mimicry
- Idiopathic thrombocytopenia
Explain what is happening in a Type II HS, with a drug reaction. What is the example used in class?
Penicillin
- penicillin binds to RBC surface proteins (hapten)
- immune response leads to complement leads to hemolysis
- Can lead to hemolytic ANEMIA
Explain what is happening in a Type II HS, with molecular mimicry. What was the example used in class?
Streptococcus
- Antibodies against strep can lead to rheumatic fever
- Antibodies target cardiac proteins
Explain what is happening in a Type II HS, with idiopathic thrombocytopenia.
Platelets are bound and killed by IgG
- we don’t know what causes it (hence, idiopathic)
Simply describe a Type III HS
Antibody-antigen COMPLEXES bound together
Describe the pathogensis of a Type III HS
- Antibodies bind with antigen and form complexes
- Large complexes are removed by phagocytes
- Small complexes deposit in microvasculature (like the glomerulus)
- Binds with complement, attracts proinflammatory basophils and neutrophils
= local inflammation and tissue damage
During a Type III HS, what are the two types of leukocytes that are attracted by the binding of complement? What do they do?
- Basophils
- cause vasodilation - Neutrophils
- release enzymes that cause blood vessel damage
What are three examples of Type III HSs?
- Serum sickness
- form complexes against the foreign serum - Systemic Lupus Erythematosus
- complexes collect in microvasculature - Rheumatoid Arthritis
- antibody-antigen COMPLEXES deposit between joints
True or False:
Rheumatoid Arthritis can be either a Type III or a Type IV HS
TRUE!
1. Antibody-antigen complexes deposit between the joints
OR
2. T-cells target synovial membrane (soft tissue) between the joints
Simply define a Type Iv HS
T-cell specific autoimmune response
True or False:
A Type IV HS has a delayed response
True
- usually 24 - 72 hours
