Hypersensitivity from the P4 Student not me Flashcards

1
Q

What is hypersensitivity

A

Hyperactive immune responses against “harmless” antigens

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2
Q

auto-immunity

A

Type of hypersensitivity that is caused by a breakdown in the mechanisms that normally ensure tolerance of self

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3
Q

What is the most common type of hypersensitivity

A

Type 1 (the allergic response)

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4
Q

What individuals are predisposed to having a type 1 hypersensitivity reaction

A

atopic indviduals

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5
Q

What type of antibodies recognize the allergen

A

IgE

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6
Q

What type of cell does the IgE antibody bind to, what part of the antibody binds

A

Mast cell, Fc

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7
Q

Where are mast cells found

A

Mucosa

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8
Q

T/F: An allergen will cross link IgE on mast cells triggering degranulation

A

True

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9
Q

What occurs when mast cells degranulate

A

allergy symptoms from mediators, recruitment of basophils from blood

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10
Q

What occurs in the late phase of type 1 hypersensitivty

A

mediators recuit other inflammatory cells (eosinophils and neutrophils)

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11
Q

What are the mediators of type 1 hypersensitvity

A

Histamine, prostaglandins, leukotrienes, TNF-alpha and IL-4

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12
Q

What does the mediator histamine cause

A

vasodilation, increased capillary permeability, smooth muscle contraction (bronchospasm)

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13
Q

What does the mediator prostaglandins cause

A

bronchoconstriction, attract white blood cells

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14
Q

What does the mediator leukotrienes cause

A

Capillary permeability (longer duration)

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15
Q

What do the mediators TNF-alpha and IL-4 do

A

inflammation, cytokine release that stimulates T helper 2 cells

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16
Q

What is an allergen

A

small inhaled proteins that stimulate IgE production in atopic individuals

17
Q

What makes an effective allergen

A

small and highly soluble, low dose, carried on dry a particles

18
Q

What is the difference in antibody production in non-atopic and atopic individuals

A

atopic individuals produce IgE, non-atopic individuals produce IgG

19
Q

T/F: Atopic individuals have more Th1 allergen specific cells

A

False: Atopic individauls have more Th2 allergen-specific cells

20
Q

How do Tregs create a bias towards T helper 2

A

Atopic individuals have defective Tregs in supressing T helper 2 cytokine production

21
Q

What the theories that as to how atopic indviduals have T helper 2 bias

A

Th2 bias developed as a fetus, lack of childhood infection may maintian T helper 2 bias, genetic predisposition toward allergic response, lack T reg response to allergen

22
Q

How does specific immunotherapy work

A

injection of gradually increasing doses of allergen causing either T helper differentiation towards 1 or IgG:IgE increases 100 fold

23
Q

What occurs in type 2 hypersensitivity (cytotoxic)

A

Antigens on a cell surface combine with antibody

24
Q

What are the three ways type 2 toxicity cause cell damage

A

complement, Ab-Ag induced cell dysfunction, complement activation attracts PMN to site causing phagocytosis

25
Q

What is the antibody that is the mediator for type 2 hypersensitvity

A

IgG

26
Q

What type of hypersensitivity causes hemolytic anemia, rhematic fever, goodpasture’s syndrome

A

Type 2

27
Q

What occurs in type 3 hypersensitivity (immune complex)

A

Ab-Ag complexes from in blood and are deposited in tissue causing cell damage

28
Q

What is the antibody that is the mediator for type 2 hypersensitivtity

A

IgG

29
Q

What are diseases/imparements that can happen from type 3 hypersensitvity

A

arthus reaction, serum sickness, rheumaotid arthrities, systemic lupus erythermatous

30
Q

What occurs in type 4 hypersensitivity (delayed)

A

The antigen is taken in by a macrophage and displayed on MHC 2, inteactions with T helper 1 causes activation of the macrophage

31
Q

What is are key differences in type 4 hypersensitivity

A

t lymphocytes instead of antibodies, starts hours or days after contact with antigen and lasts for days