Hypersensitivity

Question 1

Antigen reacts with IgE bound to mast cells

Examples:
* Anaphylaxis
* Atopy (e.g. asthma, eczema and hayfever)

Answer 1

Type I - Anaphylactic

Question 2

IgG or IgM binds to antigen on cell surface

Examples:
* Autoimmune haemolytic anaemia
* ITP
* Goodpasture’s syndrome
* Pernicious anaemia
* Acute haemolytic transfusion reactions
* Rheumatic fever
* Pemphigus vulgaris / bullous pemphigoid

Answer 2

Type II - Cell bound

Question 3

Free antigen and antibody (IgG, IgA) combine

Examples:
* Serum sickness
* Systemic lupus erythematosus
* Post-streptococcal glomerulonephritis
* Extrinsic allergic alveolitis (especially acute phase)

Answer 3

Type III - Immune complex

Question 4

T-cell mediated

Examples:
* Tuberculosis / tuberculin skin reaction
* Graft versus host disease
* Allergic contact dermatitis
* Scabies
* Extrinsic allergic alveolitis (especially chronic phase)
* Multiple sclerosis
* Guillain-Barre syndrome

Answer 4

Type IV - Delayed hypersensitivity