Brainscape's Knowledge GenomeTM

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


See full index

Immunology > Hypersensitivity > Flashcards

Hypersensitivity Flashcards

1
Q

What is hypersensitivity?

A

Immunological responses with excessive or undesirable consequences >>> that may result in tissue or organ damage

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

Types of Hypersensitivity

A

5 types:

  • Type-I
  • Type-II
  • Type-III
  • Type-IV
  • Type-V
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Who did classify hypersensitivity into 4types in 1963?

A

Gell and Coombs

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

Names of different types of hypersensitivity

A
  • Type-I: Immediate hypersensitivity, IgE-mediated, Allergy
  • Type-II: Cytotoxic hypersensitivity, Cell-bound, Antibody-mediated/dependant
  • Type-III: Immune complex mediated hypersensitivity
  • Type-IV: Delayed hypersensitivity, Cell mediated, Antibody-independant
  • Type-V: Stimulating/Inhibiting hypersensitivity, Stimulatory hypersensitivity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Type-I hypersensitivity: Main pathophysiology

A

Importants are >>>

  • IgE mediated (High IgE level)
  • Mast cell degranulation
  • Histamine release

​Antigen binds to IgE bound to mast cells > degranulation > histamin release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Type-I hypersensitivity: Mechanism

A

Allergen >>> Antigen presenting cell (APC) presents the allergen on its surface >>> Th2 recognises it >>> releases IL-4, IL-5 >>> they activate B-cells >>> B-cells become plasma cells (class-switching) >>> releases IgE antibody >>> IgE (through its Fc portion) binds to mast cell and basophil >>>

When re-exposue, Antigen binds to Fab portion of IgE >>> Then, Mast cells >>

  • Release IL-3, IL-5 >>> Eosinophil recruitment and activation
  • Mast cell degranulation >>> release of histamin, histamin-like substance & others

​>>> smooth muscle contraction, vasodilation & increased permeability

>>> Bronchospasm, Urticaria, Anaphylactic reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Type-I & type IV hypersensitivity: Time period

A

Immediate (within 24hours)

Delayed (after 24hours)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Type-I hypersensitivity: Types

A

Immediate hypersensitivity has 2 divisions:

  • Early
  • Late (But late occurs within 24hours)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Type-I hypersensitivity: Examples

A
  • Anaphylaxis
  • Hay fever
  • Asthma
  • Atopy
  • Latex allergy (when acute)
  • Eczema
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Type-II hypersensitivity: Main pathophysiology

A

Direct antibody-driven cytotoxicity

(IgG or IgM binds to antigen on the cell surface >> cell destruction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Type-II hypersensitivity: Mechanism

A

Target cells have surface antigens >>> Antibodies bind to that surface antigens (with Fab portion) >>> 3 consequences:

  • Binds to NK cells or macrophages (by Fc portion)>>> Killing/Degreadation (ADCC = Antibody dependant celullar cytotoxicty)
  • Receptor specific auto-antibody >>> interferes with signal transduction
  • Complement activation
    • ​Through MAC (Membrane attack complex) = C5b-9 >>> osmotic lysis of target cells
    • Through C3b >>> Opsonisation >>> phagocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Type-II hypersensitivity: Examples

A
  • AIHA (Autoimmune haemolytic anaemia)
  • Acute haemolytic transfusion reactions
  • ITP (Idiopathic Thrombocytopaenic Purpura)
  • Pernicious anaemia
  • Goodpasture’s syndrome (Anti-GBM Ab = IgG)
  • Rheumatic fever
  • Bullous pemphigoid
  • Pemphigus vulgaris
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Type-III hypersensitivity: Main pathophysiology

A

Immune complex deposition

Free antigen and antibody (IgG, IgA) combine

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

Type-III hypersensitivity: Mechanism

A

Phase-I: immune complex formation:

Free antigen in the circulation >>> Antigen binds on the surface of B cells >>> B cells becomes plasma cells (Class-switching) >>> releases specific antibody IgG >>> IgG bind to antigens (through Fab portion) >>> Formation of ‘immune complex’

Phase-II: Immune complex deposition:

  • Deposition in kidneys, joints, small vessels >>> tissue damage

​Phase-III: Immune complex mediated inflammation:

  • Complement C1 binds to Fc portion of IgG >>> Activation of complement cascade (classical pathway) >>> C3b binds to tissue cells & C5a attracts neutrophils (chemotaxis) >>> tissue damage
  • Neutrophil adherence: Neutrophil binds to Fc portion of IgG & C3b on tissue >>> Neutrophil degranulation: secretes lysosomal enzymes >>> fibrinoid necrosis and tissue damage
  • So, often hypocomplementaemia is present
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Type-III Hypersensitivity: Examples

A
  • EAA (Extrinsic Allergic Alveolitis)- Acute phase
  • SLE (Systemic Lupus Erythematosus)
  • Serum sickness
  • PSGN (post-streptococcal glomerulonephritis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Type-IV hypersensitivity: Main pathophysiology

A

Cell mediated (T cell driven/mediated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Type IV hypersensitivity: Main goal

A

Early elimination of responsible agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Type-IV hypersensitivity: Mechanism

A

Sensitization phase: (1-2 weeks after primary contact)

Pathogen/foreign body >>> APCs (Macrophages, Langerhans cells) recognise & presents antigen to T-helper cells >>> releases IL-12, IL-6 >>> activates CD4+ T-helper cells >>> Further activation of type-I T-helper cells (Th-1): generally (Occasionally CD8+ cytotoxic T cells)

Effector phase:

Sensitised (Effective) Th-1 cell produces IFN-gamma (also TNF-beta, IL-1, IL-2, IL-8, MCAF, GM-CSF, MIF) >>> resting macrophage >>> Activated macrophage >>> Effect of macrophage activation: high MHC/HLA class II, TNF receptor, oxygen radicals, Nitric oxide, lysosomal enzymes >>> tissue damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Type-IV hypersensitivity: Examples

A
  • Tuberculosis
  • BCG-immunisation
  • Tuberculin skin test reaction
  • Allergic contact dermatitis
  • Scabies
  • EAA (Extrinsic Allergic Alveolitis)- Chronic phase
  • Graft-vs-host disease (GVHD)
  • Latex allergy- when delayed
  • Multiple sclerosis
  • GBS

(BCG = Bacille Calmette-Guerin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Type-V hypersensitivity: Main pathophysiology

A

Stimulating/Inhibiting

(Antibodies stimulate cells they are directed against)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Type-V hypersensitivity: Mechanism

A

Antibody >>> binds to cell surface receptors (instead of cell surface) >>> either:

  • mimics the effects of ligands >>> stimulates hormone receptors OR
  • Prevents intended ligand binding >>> inhibits receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Type-V hypersesnsitivity vs Type-II hypersensitivity

A

Some suggests type-V to be under type-II hypersensitivity

  • As both are antibody driven

​But most suggests it to be an independant type (type-V), because >>>

  • Type-II causes tissue damage/destruction
  • Type-V do NOT cause damage/destruction (only stimulates/inhibits)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Type V hypersensitivity: Examples

A

Grave’s disease

Myasthenia gravis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Antibody types in Type I, II, III, V hypersensitivity

A
  • Type I hypersensitivity >> IgE
  • Type II hypersensitivity >> IgG or IgM
  • Type iii hypersensitivity >>> IgG or IgA
  • Type V hypersensitivity >>> IgG
  • Type IV is NOT antibody mediated. It is T cell mediated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Which type of hypersensitivity are related to cell and which are NOT?

A

Antibodies bind to cell:

  • Type I (IgE binds to mast cells)
  • Type II (IgG or IgM bind to antigen on cell surface)
  • Type V (IgG bonds to receptor on cell surface)

​NO cell involvement;

  • Type III (NO cell, free Ag-Ab immune complex)
  • Type IV (NO cell, NO antibodies)
26
Q

Type of hypersensitivity that does not depend upon antibody at all

A

Type-IV (Delayed, Cell mediated, Antibody independant) hypersensitivity

27
Q

Type of hypersensitivity with NO tissue damage or NO cytotoxicity

A

Type V (Stimulating/inhibiting) hypersensitivity

28
Q

What are cell-mediated and cell-bound hypersensitivities?

A
  • Cell mediated hypersensitivity is type IV (delayed, cell mediated, antibody-independant hypersensitivity)
  • Cell bound is type II (cytotoxic, antibody-mediated/dependant) hypersensitivity
29
Q

Type of hypersensitivity in Grave’s disease/Grave’s thyroid disease and Grave’s eye disease

A
  • Grave’s disease = Grave’s thyroid disease >>> Type-V hypersensitivity
  • Grave’s eye disease (ophthalmopathy) >>> Type-II hypersensitivity
30
Q

Why do Grave’s disease and Grave’s eye disease have different types of hypersensitivity?

A

We know,

Type-V hypersensitivity has antibody-mediated stimulation/inhibition (no destruction)

Type-II hypersensitivity has antibody-mediated cytotoxicity/cell destruction

As,

In Grave’s disease/Grave’s thyroid disease >>> Ab binds & stimulates hormone receptors (NO cell destruction/cytotoxicty) >>> So, Type-V

In Grave’s eye disease >>> Ab binds & causes cytotoxicity/cell destruction >>> So, Type-II

31
Q

Hypersensitivity with immediate onset-?

Hypersensitivity with delayed onset-?

A
  • Hypersensitivity with immediate onset >>> Type-I (IgE mediated, Allergy)
  • Hypersensitivity with delayed onset >>> Type-IV (Cell mediated, Antibody-independant)
32
Q

Type of Hypersensitivity that has hypocomplementaemia (low complement levels in blood)

A

Type 3 (Immune complex mediated) hypersensitivity

33
Q

Anaphylaxis >> Type of hypersensitivity

A

Type-I (Immediate hypersensitivity, IgE mediated)

34
Q

Autoimmune haemolytic anaemia (AIHA) >> Type of hypersensitivity

A

Type II (Antibody-driven/mediated, cytotoxic) hypersensitivity

35
Q

Extrinsic Allergic Alveolitis >> Type of hypersensitivity

A
  • Acute phase >> Type III (immune-complex mediated) hypersensitivity
  • Chronic phase >> Type IV (delayed, cell mediated, antibody-independant) hypersensitivity
36
Q

BCG immunisation >> Type of hypersensitivity

A

Type- IV (Delayed, Cell mediated, Antibody-independant) hypersensitivity

37
Q

Grave’s disease >> Type of hypersensitivity

A

Type V (Stimulatory) hypersensitivity

38
Q

Myasthenia Gravis >> Type of hypersensitivity

A

Type V (Stimulatory) hypersensitivity

39
Q

Graft vs Host disease (GVHD) >>> Type of hypersensitivity

A

Type IV (Delayed, Cell mediated, Antibody-independant) hypersensitivity

40
Q

SLE (Systemic Lupus Erythematosus) >> Type of hypersensitivity

A

Type III (Immune-complex mediated) hypersensitivity

41
Q

Goodpasture syndrome >> Type of hypersensitivity

A

Type II (Cytotoxic, Antibody-mediated/dependant) hypersensitivity

Anti-GBM antibody (IgG)

42
Q

Hay fever >> Type of hypersensitivity

A

Type I (Immediate, IgE mediated) hypersensitivity

43
Q

Asthma >> Type of hypersensitivity

A

Type I (Immediate, IgE mediated) hypersensitivity

44
Q

Latent TB >>> Type of hypersensitivity

A

Type IV (Delayed, cell mediated, antibody-independant) hypersensitivity

45
Q

Atopy >> Type of hypersensitivity

A

Type I (immediate, IgE mediated) hypersensitivity

46
Q

Eczema >> Type of hypersensitivity

A

Type I (Immediate, IgE mediated) hypersensitivity

47
Q

Latex allergy >> Type of hypersensitivity

A
  • When acute/immediate (within 24hours) >>> Type I (immediate, IgE-mediated) hypersensitivity
  • When delayed (After 24hours) >>> Type IV (delayed, cell-mediated, antibody-independant) hypersensitivity
48
Q

Acute haemolytic transfusion reactions >>> Type of hypersensitivity

A

Type II (Cytotoxic, antibody-mediated/dependant) hypersensitivity

49
Q

ITP (Idiopathic Thrombocytopaenic Purpura) >> Type of hypersensitivity

A

Type II (cytotoxic, antibody-mediated/dependant) hypersensitivity

50
Q

Pernicious anaemia >> Type of hypersensitivity

A

Type II (Cytotoxic, cell-bound, antibody-mediated/dependant) hypersensitivity

51
Q

Rheumatic fever >> Type of hypersensitivity

A

Type II (Cytotoxic, cell-bound, antibody mediated/dependant) hypersensitivity

52
Q

Bullous pemphigoid OR Pemphigus vulgaris >> Type of hypersensitivity

A

Both >> Type II (cytotoxic, cell-bound, antibody-mediated/dependant) hypersenisitivity

53
Q

PSGN (Post-streptococcal glomerulonephritis) >> Type of hypersensitivity

A

Type III (imuune complex mediated) hypersensitivity

54
Q

Serum sickness >>Type of hypersensitivity

A

Type III (Immune-complex mediated) hypersensitivity

55
Q

Tuberculosis >> Type of hypersensitivity

A

Type IV (Delayed, cell mediated, antibody-independant) hypersensitivity

56
Q

Tuberculin skin test reaction >> Type of hypersensitivity

A

Type IV (Delayed, cell-mediated, antibody-independant) hypersensitivity

57
Q

Allergic contact dermatitis >> Type of hypersensitivity

A

Type IV (delayed, cell-mediated, antibody-independant) hypersensitivity

58
Q

Scabies >> Type of hypersensitivity

A

Type IV (Delayed, Cell-mediated, antibody-independant) hypersensitivity

59
Q

Multiple sclerosis >> Type of hypersensitivity

A

Type IV (Delayed, cell-mediated, antibody-independant) hypersensitivity

60
Q

GBS (Guillain-Barre syndrome) >> Type of hypersensitivity

A

Type IV (Delayed, cell-mediated, antibody-independant) hypersensitivity

Immunology (16 decks)

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