Hypersensitivity and Autoimmunity

Question 1

hypersensitivity

Answer 1

a group of disorders in which the normally beneficial components of the immune response act in an exaggerated or inappropriate fashion to environmental antigens

Question 2

Types I, II , III are mediated by

Answer 2

antibodies

Question 3

Types IV is mediated by

Answer 3

the inappropriate actions of Th1 cells

Question 4

Type 1 hypersensitivity also called

Answer 4

allergy

Question 5

Type 1 hypersensitivity principally arises through…

Answer 5

inappropriate synthesis of IgE by the immune system

Question 6

Environmental antigens can be

Answer 6

Airbourne
ingested
injected
skin contact

Question 7

allergic problems can arise through a combination of

Answer 7

genetic factors
environmental factors
hormonal and neurological influences
immune regulatory factors

Question 8

Mere synthesis of IgE on its own is not enough to produce…

Answer 8

clinical allergy

Question 9

IgE associated with symptom

Answer 9

Allergy

Question 10

IgE associated with NO symptoms

Answer 10

atopy

a state of sub-clinical immune sensitisation

Question 11

what portion of the population are atopic?

Answer 11

40-50%

but only half of this have any clinical problems arising

Question 12

allergy is the end result of

Answer 12

complex interplay of a number of factors

Question 13

Allergen exposure –> mast cell –>

Answer 13

allergen specific IgE –>

release of inflammatory mediators

Question 14

Type II is mediated by

Answer 14

IgM or IgG antibodies

Question 15

IgM or IgG directed at

Answer 15

antigens on the surface of the cell or fixed within certain tissues

Question 16

In type II - once the antibody has bound to the relevant antigen - damage to tissue arises through

Answer 16

complement activation

Fc binding of immunoglobulin and stimulation of phagocytes

ADCC

Question 17

Type III arises from abnormal

Answer 17

deposition of formed antigen / antibody complexes (immune complexes) in tissues

Question 18

Immune complexes gain access to the bloodstream and are kept in

Answer 18

soluble blood and transported to the liver and spleen

Question 19

once transported the immune complexes

Answer 19

are taken up by phagocytes (such as Kupffer cells) and are destroyed

Question 20

immune complexes can be

Answer 20

physiological or pathological

Question 21

the end result of abnormal immune complexes is that they are

Answer 21

precipitated out of tissues and cause inflammation

Question 22

Serum sickness

Answer 22

immune complexes are deposited throughout many tissues

Question 23

Arthus reaction

Answer 23

complexes form locally in tissues

Question 24

Type IV

Answer 24

no antibody component

mediated by Th1 cells and the cytokine products (eg IL2 etc)

Question 25

Type IV takes places because the immune system finds it difficult to

Answer 25

destroy environmental agents

Question 26

in hypersensitivity - there is no major effect by the environment agents. the damage is don’t to the tissue by the

Answer 26

immune response

Question 27

low molecular weight agent

Answer 27

HAPTEN

Question 28

host protein

Answer 28

CARRIER

Question 29

type IV has a delay of

Answer 29

48-72 hours

Question 30

Hapten and carrier + microorganism

Answer 30

antigen uptake which gives..

Th1 antigen + cytokine production which leads to INLFAMMATION

Question 31

Autoimmune disease is mediated through aberrant cellular immunological mechanisms which are directed against

Answer 31

autoantigens

Question 32

Tolerance

Answer 32

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

Question 33

breakdown of one or more of the processes of tolerance leads to

Answer 33

autoimmune disease

Question 34

effector mechanisms involved in autoimmune disease

Answer 34

cellular T cell and B cell activity

antibody activation of complement-mediated inflammation

immune complex formation

recruitment of innate immune components

Question 35

2 important contributors to autoimmune disease

Answer 35

HLA allele

environmental factors (including infection)