Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SL - 2,3 - Respiratory Disease > Hypersensitivity > Flashcards

Hypersensitivity Flashcards

1
Q

What is Hypersensitivity?

A

Immunologically driven:

  • host tissue-damaging process.
  • tissue-irritating process.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Features of the innate immune system (IIS)

A
  • First lines of defence, general, rapid response;
  • Complement system.
  • Granulocytes:
    • Neutrophils, basophils, eosinophils, mast cells, NKs.
  • Macrophages, dendritic cells
  • Antigen Presenting Cells:
    • Macrophages, dendritic cells, follicular DCs and B cells.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Features of the adaptive immune system (AIS)

A
  • Directed by the innate immune cells, antigen-specific, memory, late response;
  • T and B cells.
  • Antibodies: ImmunogIobulins (Ig):
    • IgA, IgG, IgM, IgE, IgD.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is type 1 hypersensitivity?

A

(A) Immediate Hypersensitivity:

  • (Allergy-Anaphylaxis and Atopy):

Non-microbial environmental antigens that are innocuous (should not illicit an immune response).

Response within minutes.

Mediated by IgE-mast cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is type 2 hypersensitivity?

A

(B) Antibody Mediated:

  • IgM, IgG antiBodies against cell surface/extracellular matrix.
  • Complement-mediated.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is type 3 hypersensitivity?

A

(C) Immune Complex Mediated:

  • Soluble immune complexes Antigen-IgM or Antigen-IgG.
  • Complement-mediated.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is type 4 hypersensitivity?

A

(D) Cell Mediated (Delayed):

  • CD4 and CD8 cells.
  • Cell killing and cytokine-mediated inflammation.
  • 24-48h.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the mechanism behing type 1 hypersensitivity?

A

Antigen presenting cell (dendritic cell/macrophage) finds an antigen (Ag).

  • Presents Ag to the T cell which activates it into a Th2 phenotype.
    • Releases cytokines: IL-4 and IL-13.
      • These cytokines induce B cells to produce IgE.
        • IgE binds to the surface of mast cells (sensitised) (primed).

Once the antigen returns, it crosslinks with the antibodies on the mast cell and causes degranulation.

IL-5 activates Eosinophils.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What triggers degranulation of mast cells?

A

Crosslinking of two adjacent antibodies by an antigen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What storage granule compounds are released from mast cells?

What do they do?

A

Histamine:

  • Increased vascular permeability.
  • Smooth muscle contraction.
    • (can cause asthma this way)

Tryptase:

  • Tissue remodelling.
  • Increased mucus secretion.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the three mediators made by de novo synthesis in mast cells?

And what do they do?

A

de novo synthesis = needs activation to be produced.

Prostaglandins (PGD2):

  • Increased vascular permeability.

Leukotrienes:

  • Smooth muscle contraction.
  • Bronchoconstriction.

Cytokines:

  • Vasodilation systemic anaphylaxis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are some main characteristics of allergens?

And some exampled of some.

A

Individuals are repeatedly exposed to them.

They do not induce macrophages/dendritic cells-typical responses driving Th1/Th17.

  • (like microbes do).

Inhaled:

  • Pollens, spores, dander, dustmite.

Ingested:

  • Peanut, egg, fruits, sesame.

Venoms:

  • Bee, wasp stings and bites (Hymenoptera)

Drugs:

  • Antibiotics, chemotherapeutics.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of asthma is the allergic type?

A

Immediate asthma.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give examples of allergic mediators and the body systems/tissues they affect.

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How can we diagnose hypersensitivity (allergies)?

A

Symptoms (rapid onset):

  • Lung – asthma, wheezing.
  • Nose – rhinitis, sneezing, runny nose.
  • Eye – conjunctivitis.
  • Skin – atopic dermatitis.
  • Gut – food allergy.

All about mucosal tissues!

Skin prick test > 3mm wheal (swelling).

Laboratory tests:

  • Total IgE (>100 IU/mL).
  • Specific IgE (against a certain antigen) (e.g. RAST).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is wheal and flare?

(what mediator is it caused by?)

A

Vasodilation and vascular leak.

  • Leakage of plasma and protein (edema).
  • Vasodilation and congestion.

Caused by histamine.

17
Q

What are the mechanisms behind Type II hypersensitivity?

A

Binding of antibodies to antigens on cells / antigens on tissues;

  • Activate complement and recruit immune cells.
18
Q

What are the mechanisms behind Type III hypersensitivity?

A

Binding of Ab to Ag (self or foreign):

  • Soluble complexes not cleared.
  • Accumulation of antibody-antigen complex which drives the damage.

Activation of complement, recruitment of neutrophils and macrophages.

  • Pathologic features reflect the site of deposition;
    • Multiple tissues.
19
Q

What are the mechanisms behind Type IV hypersensitivity?

A

Delayed inflammation:

  • 24-48h after Ag challenge (instead of mins).

Antibody-independent.

  • Main drivers are the CD4 and CD8 cells.
20
Q

What are some well-known conditions resulting from type IV hypersensitivity?

A

Cytokine-mediated inflammation:

  • Inflammatory bowel disease:
    • Th1/Th17 = Crohn’s Disease.
    • Th2 = Ulcerative Collitis.

T Cell-mediated cytotoxicity:

  • Type 1 diabetes - destruction of islet cells.
21
Q

Which two types of hypersensitivity are related to asthma?

A

Types I and IV.

Type I:

  • Immediate Hypersensitivity,
    • (Allergy-Anaphylaxis and Atopy)

Type IV:

  • Cell Mediated (Delayed):
    • CD4 and CD8 cells.
    • Cell killing and cytokine-mediated inflammation.
    • 24-48h.
22
Q

How does asthma differ from COPD in terms of symptom timing?

A

Asthma has symptoms that vary over time and in intensity, together with variable expiratory airflow limitation.

  • Variable nature is how it differs from COPD.
    • i.e. reversible.
23
Q

What is the pathology of asthma with regards to inflammation?

A

Inflammatory infiltrate:

  • Inflammatory cell recruitment.
    • More Th2 cells, mast cells & eosinophils.

Mucosal oedema:

  • Bronchial microvascular leak.

Mucus hypersecretion:

  • Blockage of airways by mucus plugs.

Bronchial smooth muscle contraction:

  • Action of inflammatory mediators.
24
Q

What is the pathology of asthma with regards to remodelling?

A

Epithelial cell damage:

  • ‘leaky’ epithelium.

Reticular basement membrane thickening.

Airway smooth muscle thickening.

Submucosal mucus gland hypertrophy.

SL - 2,3 - Respiratory Disease (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions