Hypersensitivity and autoimmunity Flashcards Preview

Principles of disease JK > Hypersensitivity and autoimmunity > Flashcards

Flashcards in Hypersensitivity and autoimmunity Deck (21):
1

What are type I,II and II mediated by?

Antibodies

2

What is type 4 caused by?

Inappropriate Th1 cell action

3

What is type 1 sensitivity also known as?

Allergy

4

How does type 1 principally arise?

Inappropriate IgE synthesis

5

In type 1 what id the IgE directed towards?

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

6

What do the allergic problem arise from?

Genetic factors
Environmental factors
Hormonal and neurological influences
Immune regulatory factors

7

Atopy

A state of sub-clinical immune sensitisation

8

What are type 1 allergic reaction mediators?

Histamine
Mucosal oedema
Vasodilation

9

What is type 2 hypersensitivity mediated by?

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

10

What can the antigens be?

Exogenous or derived from self

11

What happens in type 2?

Complement activation stimulate phagocyte
Inhibit function

12

How do clinical conditions in type 3 arise?

Abnormal deposition of formed antigen or antibody in tissues

13

Pathological immune complex inflammation

Deposited in many tissues - serum sickness
Complexes formed locally in tissues - arthus reaction

14

Why do type 4 reactions occur?

Immune system finds it difficult to destroy these environmental agents

15

What are type 4 mediated by?

Cytokines products eg interleukin-2 and interferon
Th1 cells

16

Hapten

Low molecular weight agent

17

Carrier

Host protein

18

How much of a delay is there in type 4?

48-72 hours

19

Tolerance

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

20

Effector mechanisms in autoimmunity

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

21

Important contributants to autoimmunity

Genetic factors - HLA alleles