tyoe 1 hypersensitivity Flashcards

1
Q

Hypersensitivity Reactions

A

Activation of immune system in the absence of a danger

Resulting in tissue damage, discomfort and even death

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2
Q

Type 1 Hypersensitivity

A

immediate HSR

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3
Q

Type 1 Hypersensitivity Immune Reactant

A

IgE

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4
Q

Type 1 Hypersensitivity Antigen

A

Soluble antigen

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5
Q

Type 1 Hypersensitivity Effector Mechanism

A

Mast-cell activation

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6
Q

Type 1 Hypersensitivity Examples

A

allergic rhinitis, asthma, system anaphylaxis

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7
Q

Allergen

A

a stimulus

Harmless environmental substance that induces an allergic response

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8
Q

Anaphylaxis

A

A rapidly progressing allergic reaction, could be life-threatening

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9
Q

Atopy

A

Familial predisposition

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10
Q

Initiating cells

A

APC, Th0, Th2 and B cells

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11
Q

Common Allergens

A

Low molecular weight proteins

Must contain peptides that bind to host MHC Class II molecules

Favor activation of IL-4 producing Th2

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12
Q

IgE

A

very low serum concentrations

Fc region binds to the FcϵR on the effector cells

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13
Q

Sensitization phase

A

IgE antibody bind to mast cells, basophils and eosinophils via FcϵR1

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14
Q

Activation phase

A

Re-exposure to an antigen cross links cell bound IgE and activates mast cells to degranulate

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15
Q

Effector phase

A

many pharmacologically active agents released by the mast cells and basophils

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16
Q

Tho -> Th2

17
Q

B cell -> Th2

A

IL-4

IL-13

18
Q

Th2 -> Eosinophil

19
Q

recruit eosinophils to tissue of reaction

20
Q

Mast cells can be activated by

A

PRR such as Toll like receptors

Fc receptor for IgA and IgG

C5a, C3a, C4a 

Chemicals (drugs) 

Stress

21
Q

inhinbits COX

22
Q

Systemic anaphylaxis

A

allergens reaching the blood steam

23
Q

Inhaled antigens: Asthma

A

cute response in allergic asthma leads to Th2 mediated chronic/late inflammation of the air way

24
Q

TGF beta promotes

A

class switch to IgG/IgA

25
Diagnosis of Type I HSR
Skin test: Wheal and Flare Reaction ``` 2. RAST: RadioAllergoSorbent Test (detects allergen specific IgE) - no IgE = no allergy ``` 3. Tryptase and histamine serum level: Anaphylaxis
26
(pharmalogical treatment) Prevent IgE mediated mast cell degranulation
Sodium cromoglycate
27
(pharmalogical treatment) Block mediators by blocking receptors
Anti-histamines
28
(pharmalogical treatment) Reverse the action of mediators
Epinephrine
29
(pharmalogical treatment) Anti-inflammatory agents
Steroids – nasal spray
30
Immunological treatment
Desensitization Monoclonal antibodies Correction of Th1/Th2 balance
31
Desensitization
Allergy shots Correct isotype switch from IgE to IgG
32
Monoclonal antibodies
Anti IL-4, IL-13, IL-5 and IgE Omalizumab (IgE specific) Mepolizumab (IL-5 specific)