What are Type I Hypersensitivities?
- IgE mediated
- Occurs when antigen makes contact with body, and binds to receptors on mast cells and basophiles
- Characterized by immediate reaction of individual
- Can be local anaphylaxis - one spot, or generalized anaphylaxis - whole body
What is anaphylaxis?
Name given for IgE mediated allergic reactions
Types of localized anaphylaxis:
- Hives - wheal and flare rash
- Hay fever - teary eyes, sneezing, runny nose
- Asthma - inflamed respiratory tract
What is generalized anaphylaxis?
- Antigen enters blood stream and becomes wide spread
- May induce shock
What is immunotherapy/densensitization/hyposensitization?
Technique used to modify immune system by injecting individual with extremely diluted suspension of allergen
What are Type IV Hypersensitivities?
- Delayed hypersensitivities caused by cell mediated immunity.
- T-Cells are responsible
- Body slowly develops a response to antigen
- Responsible for contact dermatitis, rejection of tissue grafts, some autoimmune diseases.
- TB test
How do T-Cells cause Type IV Hypersensitivities?
T-Cells release cytokines, which initiate inflammation, which attracts macrophages
Examples of contact hypersensitivities - type IV?
- Poison Ivy/Oak
- Nickel in metal jewelry
- Chromium salts in leather
- Latex products
What is an auto-immune disease?
A disease that causes the body to attacks its own tissues