Allergic Disease Flashcards Preview

Clinical Pathology > Allergic Disease > Flashcards

Flashcards in Allergic Disease Deck (44):
1

Hypersensitivity

Undesirable, damaging or discomfort producing reactions produced by the normal immune system, directed against inocuous antigens in a pre-sensitised (immune) host

2

Type II hypersensitivity

Cytotoxic

3

Immunopathogenesis of Type II hypersensitivity

IgG/IgM Ab response against combined self/foreign antigen at the cell surface-complement activation/phagocytosis.

4

Clinical features for type II hypersensitivity

Mins to hours. Cell lysis and necrosis.

5

Common antigen for type II hypersensitivity

Penicillin

6

Associated diseases with type II hypersensitivity

erythroblastosis fetalis, goodpasture's nephritis. Rh reaction with mother/foetus.

7

Type III hypersensitivity reaction

Immune complex

8

Immunopathology of type III hypersensitivity reaction

IgG/IgM Ab against soluble antigen-immune complex deposition.

9

Clinical features of type III hypersensitivity

Onset 3-8 hours. Vasculitis.

10

Traditional cause for type III hypersensitivity reaction

Serum sickness

11

Associated diseases for type III hypersensitivity reaction

SLE

12

Type III reaction to IV route of antigen

Vasculitis, arthritis, nepthritis

13

Type III reaction to SC route of antigen

Arthus reaction-perivascular area

14

Type III reaction to inhaled route of antigen

Farmer's lung

15

Type IV hypersensitivity reaction

Delayed- no Ab involved

16

Immunopathology of type IV hypersensitivity

Antigen specific T cell mediated cytotoxicity

17

Clinical features of type IV hypersensitivity

Metals e.g. nickel (tuberculin reaction)

18

Associated diseases of type IV hypersensitivity

Contact dermatitis

19

Immunopathology of type 1-anaphylaxis IgE mediated hypersensitivity

Increased IgG levels
Tissue inflammation with eosinophils, mastocytosis, basophil infiltration.
Presence of CD4 cells secreting Il4, Il5, Il13

20

Hygeince hypothesis

More exposure to infections, less allergies. Mechanisms is Th1-Th2 deviation (Th1-infection, Th2-allergy)

21

Association between genetics and rhinitis

None, as opposed to asthma and atopic dermatitis

22

What happens to the T cell activation in allergic reactions

Treg pathway suppressed, Th1 and Th2 pathways are activated.

23

IgE Abs are induced by which cytokines?

Il-4

24

Sensitisation

B cells activated by Th2 cells-produce IgE Abs, induced by Il-4 cytokines

25

What happens when an allergen is in contact with a pre sensitised host?

Antigen binds to fab region of IgE on sensitised mast cell, triggering the release of vasoactive amines.

26

Immunopathogenesis of type I hypersensitivity

IgE Ab mediated mast cell and basophil degranulation-release of preformed and de novo synthesised inflammatory mediators.

27

Clinical features of tyep I hypersensitivity

fast onset (15-30 mins) wheal and flare

28

Late phase response of type I hypersensitivity

Eosinophils, central role for Th2 T cell

29

Describe the initial response of the mast cell in type I hypersensitivity, following antigen binding to IgE on surface of mast cell

Degranulation-histamine, proteases, chemotactic factors

30

Describe the late phase reponse of mast cell activation in type I hypersensitivity

Cytokines
Arachidonic acid-leukotrienes and prostaglandins

31

3 roles of the Th2 cell

Activates B cells-drives Ab production
Activates macrophages-innate inflammatory response
Activates other cells-multiple cytokine release

32

3 parts of the atopic triad and what form of hypersentivity each of them are

Rhinitis- 1
Asthma- 1
Atopic dermatitis- 4

33

Is astham in the upper or lower airways?

Lower

34

Which cytokine triggers pruritis (scratch)

IL-31

35

Anaphylaxis

Acute, potentially life threatening, IgE mediated systemic hypersensitivity reaction. 3 types- 3 most severe.

36

Allergic status is given if you have a specific IgE level of what?

greater than o.35kua/L

37

What is positive result for the skin prick test?

>3mm wheal

38

Describe the skin prick test

-ve control: saline solution (shouldn't react)
+ve control: histamine (everyone should react)
Pollen/potential antigen

39

Describe the basophil activation test

If sensitised, basophils will be activate by antigen -blood test

40

4 types of tests for allergices

Skin prick test
Intra-dermal test
Oral challenge
Basophil activation test

41

Mechanisms of immunotherapy

Switching pathways from Th2-Th1 or inducing Treg pathway. Modifying T cells to activate B cells to make different antibodies.

42

Describe the skin prick test

-ve contcol e.g. saline solution
+ve control e.g. histamine
Potential antigen
+ve result if greater than 3mm wheal

43

Name 4 allergy tests

Skin prick test
Intradermal test
Oral challence
Basophil activation test (blood test)

44

Mechanisms of immunotherapy

Switching pathways Th2-Th1 or inducing Treg pathway.
Modifying T cells to activate B cells to make different antibodies