Lecture 17 - Allergies and other Hyper-sensitives Flashcards
What is hypersensitivity?
An excessive immune response to harmless antigens
How are immune hypersensitives hindering medical intervention?
People develop allergies to commonly used drugs such as penicllin
What is a type-1 allergic reaction?
- Airway hypersensitivity
- Lung epithelium inlfammation
What causes a type-1 allergic reaction?
- Expose to allergen stimulating type 2 helper T cells
- Causes inflammatory response
What can the improper activation of Mast-cells cause in the GI tract?
- Increased fluid secretion
- Causes diarrhoea and vomiting
What can the improper activation of Mast-cells cause in the Airways?
- Decreased siameter, and increased mucus secretion
- Causes Swelling in nasal passages
What can the improper activation of Mast-cells cause in the Blood vessels?
- Increased blood flow and permeability
- Causes increased fluid in the tissues
What causes a Type-2 hypersensitive allergic reaction?
Over production of IgG or IgM reacting with antigens on cells or tissues
List three problems that may arise from Type-2 hypersensitivity. [3]
- Blood transfusion reactions
- Haemolytic disease of the newborn
- Drug induced hypersensitivity
How do blood transfusion reactions occur?
- Wrong blood type transfused
- IgM binds to new blood
- Activates the complement
How does Haemolytic disease of the newborn occur?
- Rh- mother gains memory cells for Rh antigens
- Second Rh+ child is conceived
- Mother’s antibodies attack the fetus’ blood
What causes type-3 hypersensitivity?
Caused by immune complexes of antigen and antibody
What is serum sickness?
- Animal serum stimulates strong antibody response
- Can cause fever, rash, kidney disorder etc
What causes type-4 hypersensitivity?
- Involves Th, Tc, and macrophages
What does immunity to Th2 lead to?
Resistance to parasitic worm infection
