Hypersensitivity and Autoimmunity

Question 1

Which types of hypersensitivity are mediated via antibodies?

Answer 1

Type I, II and III

Question 2

What is type IV hypersensitivity caused by?

Answer 2

The inappropriate action of T1 helper cells

Question 3

How does type I hypersensitivity arise?

Answer 3

Inappropriate synthesis of IgE antibodies by the immune system, which are directed against environmental antigens

Question 4

State the ways the body can interact with allergens? (4)

Answer 4

• Airborne
• Inhaled
• Injected
• Skin contact

Question 5

State what is meant by the term ‘atopy’

Answer 5

A genetic tendency to develop allergic diseases

Question 6

Describe the pathogenesis of allergy.

Answer 6

• Allergen exposure

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Question 7

State what is meant by the term ‘autoimmune disease’

Answer 7

A large group of clinical disorders characterised by tissue or organ damage mediated by incorrect immune mechanisms targeted at self-antigens.

Question 8

In type III hypersensitivity, immune complexes are formed from a high/low conc. of antibody and a high/low conc. of antigen.

Answer 8

Low conc. of antibody

High conc. of antigen

Question 9

Cytokines come from

Answer 9

Mast cells in type I

CD4 helper T cells in type IV

Question 10

Late phase reactions involve _____ mediators

Answer 10

Eosinophil mediators

Question 11

State the systemic effects of type III hypersensitivity.

Answer 11

Immune complexes are deposited in tissues and organs such as:

• Blood vessel
• Skin
• Joints
• Kidneys