Hypersensitivity: Summary

Type I Hypersensitivity:

 • Immunological Mediator: lgE

 • Immunological Target: Allergen Molecules

 • Ex: Antibiotic allergies (ex. penicillin & cephalosporin), Food allergies (ex. peanuts), Hay fever, Urticaria, Allergic conjunctivitis

Type II Hypersensitivity:

 • Immunological Mediator: IgM + IgG

 • Immunological Target: Modified cell surfaces

 • Ex: Autoimmune thrombocytic purpura, Heparin induced thrombocytopenia, Autoimmune Hemolytic anemia, Penicillin-induced drug reaction, Myasthenia Gravis, Graves' Disease

Type III Hypersensitivity:

 • Immunological Mediator: IgG

 • Immunological Target: Antigen-Ab immune complexes

 • Ex: Systemic Lupus Erythematosus, Reactive Arthritis, Post-infectious glomerulonephritis, Serum sickness

Type IV Hypersensitivity:

 • Immunological Mediator: Th Cells

 • Immunological Target: Allergen molecules

 • Ex: Stevens-Johnson Syndrome, Contact Dermatitis (ie. reaction to poison ivy)



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