1. ALLERGIC REACTIONS Localized Anaphylaxis

2. ATOPIC DISEASES Localized anaphylaxis (common allergy) ~20% of US population Limited production of IgE and sensitization of mast cells in localized areas Ex: Allergic rhinitis

3. LATE-PHASE ANAPHYLAXIS Takes several hours for inflammation to show Mast cells release chemotactic factors Eosinophils Neutrophils Helper T Cells

4. ASTHMA Triggers 2 parts Early response – mast cells in lower respiratory tract Late response – eosinophils and neutrophils Treatments

5. FOOD ALLERGIES GI tract reaction Hives = wheal and flare

6. ECZEMA Atopic dermatitis IgE levels elevated Rash and itching Increased eosinophils and helper T cells Allergen unknown

7. WHY HYPERSENSITIVITY? B cells that produce IgA vs. B cells that produce IgE Atopic individuals have lower levels of IgA Suppressor T lymphocytes stop production of IgE – defective in atopic individuals

8. ALLERGIES POSITIVE? Sneezing GI contractions Resistance to pathogens Hygiene hypothesis

9. TREATMENT OF ALLERGIES Desensitization types Tiny but increasing doses of allergens Series of injections of allergens over weeks -- blocking antibodies Monoclonal antibodies – anti-IgE antibodies