Hypersensitivity ☺️

Question 1

Describe the T1 response

• pathophysiology
• examples
• presentation
• testing

Answer 1

IMMEDIATE HYPERSENSITIVITY
-allergy, atopy, anaphylaxis

Antigen reacts with IgE bound to mast cell

• histamine - vascular permeability, BC, VD => wheal and flare
• tryptase - tissue remodeeling, mucosecretion
• PGI, LT, cytokines

Resp 
-BC, wheeze
-rhinitis, sneeze
Eye
-conjunctivitis
Skin
-AD
GI
-food allergy

Skin prick
Total IgE, specific IgE (RAST)
Transient increase of tryptase

Question 2

Describe the T2 response

• pathophysiology
• examples

Answer 2

AB-AG on cells/tissue => complement cascade
Opsonisation => phagocytosis
-AI hemolytic anemia
-Haemolysis in transfusion

Complement, Fc inflammation

• Glomerulonephritis
• ANCA vasculitis

AB inappropriately changes processes

• Myasthenia gravis
• Graves

Question 3

Describe the T3 response

• pathophysiology
• examples

Answer 3

Accumulation of AB-AG complexes => immune response

• SLE
• post strep GN
• serum sickness

Question 4

Describe the T4 response

• pathophysiology
• examples

Answer 4

delayed cell mediated response via

• cytokines => inflammation
• T cell mediated damage

Asthma, IBD
T1D
Myocarditis