Hypersensitivity and autoimmunity Flashcards Preview

Principles of disease JK > Hypersensitivity and autoimmunity > Flashcards

Flashcards in Hypersensitivity and autoimmunity Deck (21)
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1
Q

What are type I,II and II mediated by?

A

Antibodies

2
Q

What is type 4 caused by?

A

Inappropriate Th1 cell action

3
Q

What is type 1 sensitivity also known as?

A

Allergy

4
Q

How does type 1 principally arise?

A

Inappropriate IgE synthesis

5
Q

In type 1 what id the IgE directed towards?

A

Antigens that may be airborne, ingested, skin contact or injected

6
Q

What do the allergic problem arise from?

A

Genetic factors
Environmental factors
Hormonal and neurological influences
Immune regulatory factors

7
Q

Atopy

A

A state of sub-clinical immune sensitisation

8
Q

What are type 1 allergic reaction mediators?

A

Histamine
Mucosal oedema
Vasodilation

9
Q

What is type 2 hypersensitivity mediated by?

A

IgG or IgM antibodies directed against antigens found on the surface of cells or fixed within certain tissues

10
Q

What can the antigens be?

A

Exogenous or derived from self

11
Q

What happens in type 2?

A

Complement activation stimulate phagocyte

Inhibit function

12
Q

How do clinical conditions in type 3 arise?

A

Abnormal deposition of formed antigen or antibody in tissues

13
Q

Pathological immune complex inflammation

A

Deposited in many tissues - serum sickness

Complexes formed locally in tissues - arthus reaction

14
Q

Why do type 4 reactions occur?

A

Immune system finds it difficult to destroy these environmental agents

15
Q

What are type 4 mediated by?

A

Cytokines products eg interleukin-2 and interferon

Th1 cells

16
Q

Hapten

A

Low molecular weight agent

17
Q

Carrier

A

Host protein

18
Q

How much of a delay is there in type 4?

A

48-72 hours

19
Q

Tolerance

A

The process by which the immune system avoids producing damaging reactions against self antigens

20
Q

Effector mechanisms in autoimmunity

A

T cell and B cell
Immune complex formation
Recruitement of innate compound

21
Q

Important contributants to autoimmunity

A

Genetic factors - HLA alleles