Lecture 2 - Hypersensitivity (Dr. Stiner) Flashcards

1
Q

What is hypersensitivity?

A

Exaggerated or aberrant immune response to an antigen

Results in inflammation and tissue damage

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2
Q

How many types of hypersensitivity reactions are there?

A

4

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3
Q

What is the immune reactant for Type I hypersensitivity?

A

IgE

Mast cell activation

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4
Q

What are some examples of Type I hypersensitivity (IgE)?

A

allergic rhinitis
asthma
systemic anaphylaxis

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5
Q

What is the effector mechanism for Type I hypersensitivity?

A

Mast cell activation

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6
Q

What is the immune reactant for Type II hypersensitivity?

A

IgG

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7
Q

IgG is involved in ______ hypersensitivity.

A

Type II

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8
Q

Drug allergies are examples of Type ___ hypersensitivity (immune reactant ___)

A

Type II, IgG

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9
Q

What are some IgE mediated allergic reactions?

A
  1. Systemic anaphylaxis
  2. Acute Urticaria (wheal and flare)
  3. Allergic rhinitis (hay fever)
  4. Asthma (most common)
  5. Food Allergy
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10
Q

Systemic anaphylaxis route of entry.

A

intravenous (either directly or following oral absorption into the blood)

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11
Q

Acute Urticaria (wheal and flare ) route of entry.

A

Through skin.

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12
Q

Allergic rhinitis (hay fever) route of entry.

A

inhalation

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13
Q

Asthma route of entry.

A

Inhalation

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14
Q

Food Allergy route of entry.

A

oral

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15
Q

Systemic anaphylaxis response

A
edema
vascular permeability
trachea closes
circulatory collapse
death
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16
Q

Acute urticaria (wheal and flare; hives) response

A

local increase in blood flow and vascular permeability

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17
Q

hay fever (season allergies; allergic rhinitis) response

A

edema of nasal mucose

irritation of nasal mucosa

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18
Q

Asthma response

A

bronchial constriction
increased mucous production
airway inflammation

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19
Q

food allergy response

A
vomiting
diarrhea
pruritis (itching)
urticaria (hives)
anaphylaxis (rarely)
20
Q

What is pruritis, and what is it a response to?

A

itching; food allergy

21
Q

What is urticaria, and what is it a response to?

A

hives; acute utricaria & food allergy

22
Q

Type I hypersensitivity occurs w/in minutes after _______ to antigen/allergen

A

REEXPOSURE

23
Q

What is the most common disorder of the immune system?

A

Type I Hypersensitivity
IgE & mast cell reaction
affects 20% of population

24
Q

What are some examples of Type I hypersensitivity?

A

hives, hay fever, food allergies, bronchial asthma, anaphylaxis

25
Q

What are the two phases of type 1 hypersensitivity response?

A
  1. SENSITIZATION interaction (develop antibodies)

2. second interaction = hypersensitivity

26
Q

Release of mediators triggers a biphasic response to the allergen/antigen.

A
  1. Immediate Effects

2. Late Response

27
Q

What are the Immediate Effects of the biphasic response of Type I hypersensitivity?

A

Dilation of blood vessels
increased vascular permeability
smooth muscle contraction
(immediate!)

28
Q

What is the late phase (second phase) reaction of Type I hypersensitvity?

A

inflammation

29
Q

What are some mechanisms of the Immediate Response of Type I hypersensitivity?

A
  1. Vasoactive Amines (histamine and serotonin) and proteases
  2. synthesis and secretion of LIPID MEDIATORS
    • Prostaglandins and Leukotrienes
30
Q

What are the lipid mediators that are synthesized and secreted during the IMMEDIATE RESPONSE of type I hypersensitivity?

A

Prostaglandins

Leukotrienes

31
Q

What are the effects of prostaglandins (lipid mediator)

A

VASOCONSTRICTION IN THE LUNGS

32
Q

What are the effects of Leukotrienes (lipid mediator)

A

BRONCHOCONSTRICTION

INCREASED VASCULAR PERMEABILITY

33
Q

What happens during the LATE RESPONSE of the type I hypersensitivity?

A
  1. Synthesis and secretion of cytokines and chemokines

2. Infiltration of eosinophils, monocytes, and neutrophils

34
Q

What do eosinophils release?

A

ROS
major basic protein
prostaglandins
leukotrienes

35
Q

What do ROS and major basic protein do?

A

tissue damage and inflammation

36
Q

IgE + allergen –> Fc interaction on surface of mast cell =

A
  1. cytokines
  2. histamine granules
  3. lipid mediators
    • prostaglandins and leukotrienes
37
Q

What are the most common signs of asthma?

A

Coughing
Wheezing
Shortness of Breath

38
Q

What are some asthma triggers?

A

Airborne allergens
pollen, animal dander, mold, cockroaches, and DUST MITES

respiratory infections (common cold)

Physical activity

cold air

air pollutants and irritants (smoke)

39
Q

Asthma Tx

A
  1. INHALED CORTICOSTERIODS
    • relieve airway inflammation
  2. beta2 agonists
  3. LEUKOTRIENE MODIFIERS
    • block chain rxn that creates airway inflammation
  4. CROMOLYN
    • prevent mast cell degranulation that leads to bronchial constriction and inflammation
40
Q

What determines the type of IgE-mediated allergic reaction that occurs?

A

the dose and routes of entry of allergens

41
Q

What are the two factors that drive the anaphylactic response?

A
  1. vasoactive amines

2. lipid mediators

42
Q

What are the 2 symptoms of anaphylaxis?

A
  1. drop in BP

2. severe bronchioconstriction

43
Q

How is anaphylaxis treated?

A
  1. epinephrine
    • vasoconstrictor
    • bronchiodilator
  2. antihistamine
44
Q

What 2 events occur as a result of mast cell activation?

A
  1. mast cell degranulation
  2. synthesis and secretion of lipid mediators
  3. Cytokine release
45
Q

Let’s talk about Type II hypersensitivity.

A

Okay