Hypersensitivity and Autoimmunity

Question 1

Define 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 which don’t usually cause the tissue damage.

Question 2

What is responsible for the tissue damage?

Answer 2

Exaggerated immune response.

Question 3

What are hypersensitivity types 1, 2 and 3 mediated via?

Answer 3

Antibodies.

Question 4

What cause type 4 hypersensitivity?

Answer 4

Inappropriate actions of T helper 1 cells

Question 5

What is the other name for type 1 hypersensitivity?

Answer 5

Allergy

Question 6

What is type 1 hypersensitivity caused by?

Answer 6

Inappropriate synthesis of IgE.

Question 7

In what 4 ways can a type 1 hypersensitivity reaction be started?

Answer 7

Ingestion
Inhalation
Injection
Skin contact

Question 8

What are allergens?

Answer 8

Antigens which cause IgE production.

Question 9

What are the 5 factors of immunity? RIREC

Answer 9

Recognition
Interaction
Response
Elimination
Control and Regulation

Question 10

What allows IgE to bind to Fc receptors?

Answer 10

It has an extra peptide sequences to other immunoglobulins.

Question 11

Where are Fc receptors found?

Answer 11

On the surface of mast cells.

Question 12

What do T helper cells do?

Answer 12

Aid B-cells in producing IgE

Question 13

What are the 3 types of Th1 cells?

Answer 13

IL-2
Gamma - IFN
TNF

Question 14

What are the 4 types of Th2 cells?

Answer 14

IL- 4
IL - 6
IL - 10
IL - 13

Question 15

Define atopy.

Answer 15

A genetic tendency to produce IgE to normally innocuous, common environmental allergens.

Question 16

Define allergy.

Answer 16

A clinical expression of the atopic tendency.

Question 17

What % of the population suffers from allergy?

Answer 17

15-20%.

Question 18

What are 3 specific triggers of IgE?

Answer 18

Insect venom
Pollen
Mould spores
Animal dander
Food allergens

Question 19

What are 3 nonspecific triggers of IgE?

Answer 19

Exercise
Tobacco
Pollution
SO2
Water
Food items

Question 20

What are the 5 symptoms of allergy and atopy?

Answer 20

Anaphylaxis
Asthma
Rhinitis and Conjunctivitis
Urticaria
Gastrointestinal

Question 21

What is the main preformed mast cell mediator?

Answer 21

Histamine

Question 22

What are the 2 newly synthesised mast cell mediators?

Answer 22

Prostaglandins

Leukotrienes

Question 23

What mast cell causes early phase response?

Answer 23

Preformed

Question 24

What mast cell causes late phase response?

Answer 24

Newly synthesised

Question 25

What 2 things mediate type 2 hypersensitivity?

Answer 25

IgG | IgM

Question 26

What are the target antigens in type 2 hypersensitivity?

Answer 26

Self | Exogenous

Question 27

Where are the target antigens found in type 2 hypersensitivity?

Answer 27

on the surface of or fixed within cells.

Question 28

In what 4 ways does damage to tissue arise in type 2 hypersensitivity?

Answer 28

Complement activation Fc receptor-mediated damage Antibody dependent cellular cytotoxicity Effects on target function i.e inhibition

Question 29

What are the 2 types of immune complex formation?

Answer 29

Normal | Pathological

Question 30

What is formed in an immune complex formation?

Answer 30

Lattice due to antigens having 2 binding sites.

Question 31

What are the 3 protective mechanisms of a normal immune complex?

Answer 31

Opsonization Transportation Destruction

Question 32

What causes the clinical conditions to arise in in type 3 hypersensitivity?

Answer 32

Abnormal deposition of formed antigen/antibody complexes in tissues.

Question 33

What is the process of serum sickness?

Answer 33

Immune complexes form in circulation causing systemic deposition in tissues.

Question 34

What is the process of arthus reaction?

Answer 34

Immune complexes form locally in tissues.

Question 35

What happens to immune complexes formed normally after gaining access to the blood stream?

Answer 35

Kept soluble in the blood and transported to the liver and spleen for phagocytosis.

Question 36

What is the job of Th1 cells in type 4 hypersensitivity?

Answer 36

Mediator

Question 37

In general, why do type 4 hypersensitivity reactions take place?

Answer 37

As the body's immune system finds it hard to destroy the environmental agents causing the problem.

Question 38

What is a hapten?

Answer 38

The low molecular weight agent which has so bind to a carrier to produce an antigenic stimulus of sufficient size for a response.

Question 39

How long a delay is there is type 4 hypersensitivity?

Answer 39

48-72 hours

Question 40

The hapten is ___genous and the carrier is ___genous.

Answer 40

Exo, endo.

Question 41

Define autoimmune disease.

Answer 41

A large group of clinical disorders which are characterised by tissue or organ damage mediated through immunological mechanisms which are directed against autoantigens.

Question 42

What is another name for autoantigens?

Answer 42

Self antigens

Question 43

What are the two types of roles an autoantigen can do?

Answer 43

Non-organ specific | Organ specific

Question 44

Define tolerance.

Answer 44

The process whereby the immune system avoids producing damaging reactions against self antigens.

Question 45

How does central tolerance arise?

Answer 45

Deletion of autoreactive T and B cells.

Question 46

How does peripheral tolerance arise?

Answer 46

Inhibiting the activity of autoreactive cells which escape the central tolerance process.

Question 47

What is the breakdown of a tolerance process a requirement for?

Answer 47

Autoimmune disease

Question 48

What are the 5 aetiologies of autoimmune disease?

Answer 48

``` Genetic factors Immune regulatory factors Hormonal factors Environmental factors Other factors ```

Question 49

What are the 5 effector mechanisms of autoimmune disease? (Pathogenesis)

Answer 49

``` Cell mediated Antibody mediated Antibody and complement Immune complex mediated Recruitment of innate components ```

Question 50

What type of disease is organ specific?

Answer 50

Diabetes

Question 51

What type of disease is non-organ specific?

Answer 51

Connective tissue