Harmful effects of hypersensitivity to environmental (exogenous) antigens
Hypersensitivity: Autoimmunity
Disturbances in the immunologic tolerance of self-antigens
Hypersensitivity: Alloimmunity
Immune reaction to tissues of another individual
Type 1
IgE mediated
Type 2
•Tissue-specific reactions
-Cell destruction by antibody and complement
-Cell destruction through phagocytosis
Type 3
Type III
•Immune complex mediated
-antibodies bind to soluble antigen that was released into the body or fluids, and then the complex is deposited into tissue
Type 4
•Cell mediated
-mediated by T lymphocytes; DO NOT involve antibody
Type 1
•Genetic /Hereditary in origin
•Clinical Manifestations
1. urticaria
2. rhinitis
3. mild breathing problems
4. pruritis
5. edema
Allergy
Allergy
•Environmental antigens that cause atypical immunologic responses in genetically predisposed individuals •Pollens, molds and fungi, foods, animals, etc.•Symptoms range from annoying to life threatenin
Allergy Leading to Anaphylaxis
•Most rapid and severe immediate Type 1 hypersensitivity reaction
-Occurs within minutes of reexposure to antigen
-Systemic or cutaneous
-Most severe reactions can lead to shock and death
-Common causes are beestings or eating peanuts, shellfish, or eggs