Hypersensitivity and autoimmunity

Question 1

What is an autoimmune disease?

Answer 1

Failure or break down of immune system which maintains tolerance to self-tissues

Question 2

Provide examples of different ways to treat autoimmune disease

Answer 2

Blanket immunosuppression
Target selective approach-target the aberrant(not normal) immune activation
Leaves the rest of the immune system intact

Question 3

Define hypersensitivity

Answer 3

Hyper response from immune system

Question 4

How many types of hypersensitivity are there?

Answer 4

4

Question 5

Describe type 1 hypersensitivity

Answer 5

-IgE
-Soluble antigen(allergen)
-Allergy

(•|Body recognises environmental antigen as a pathogen and releases IgE and triggers Mast cell responses.
• Release of cytokines from mast cells

Question 6

Describe type 2 hypersensitivity

Answer 6

-IgG
-Cell or matrix antigen
-AIHA or rhematic fever

(• Antibodies bind to antigens on its own cell surfaces.
• Antibodies are produced in response to antigens on cell surfaces
• IgG and IgM antibodies trigger complement system causing cell lysis

Question 7

Describe type 3 sensitivity

Answer 7

-IgG
-Soluble antigen
-SLE-lupus-attacks own tissue
-Arthritis
(• Characterised by the formation of immune complexes
• A low conc. of antibody coupled with a large conc. of antigen causes small complexes to form)

Question 8

Describe type 4 sensitivity

Answer 8

• Th1, Th2, CTL
• soluble antigen, cell
• antigen,inf-gamma
  Type 1 diabetes
  (• The body’s CD4 helper T cells recognise the foreign antigen
  Produce cytokines which leads to inflammatory response. )

Question 9

Describe central tolerance

Answer 9

The process of eliminating lymphocytes that are self reactive

Question 10

Describe peripheral tolerance

Answer 10

The process of eliminating T cells which avoided central tolerance

Question 11

What type of lymphocytes acquire peripheral tolerance?

Answer 11

Mature lymphocytes in the peripheral tissue

Question 12

What type of lymphocytes acquire central tolerance

Answer 12

Immature lymphocytes during their development

Question 13

How may self reactive lymphocytes escape negative selection?

Answer 13

due to low affinity to self MHC/antigen and the exclusive expression of some proteins in the periphery

Question 14

Name some factors which affect auto-immune diseases?

Answer 14

Genetic predispositions
Hormonal/sex
Environmental co-factors
Immunity regulatory factors

Question 15

Describe systemic autoimunne disease

Answer 15

Systemic
Autoimmune process is spread throughout the body - affects more than one organ.

Question 16

Describe organ specific autoimmune disease

Answer 16

Autoimmune process directed against one organ. eg type 1 diabetes

Question 17

What type of hypersensitivity is SLE

Answer 17

type 3

Question 18

What type of hypersensitivity is diabetes mellitus

Answer 18

type 4

Question 19

What type of hypersensitivity is arthritis

Answer 19

Type 3

Question 20

Compare immediate and late phase responses

Answer 20

Immediate
-IgE mediated effects
-Vasodilation, oedema & vascular conjestion
Late phase response
-Eosinophil, neutrophil & T cell infiltrates

Question 21

What does Atopy mean

Answer 21

Predisposition to allergy

Question 22

What hypersensitivity reactions are antibody mediated

Answer 22

Type I,II, III

Question 23

Which hypersensitivity reaction is T cell mediated

Answer 23

Type IV