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Lecture 16 Allergy

Lecture 16 Allergy. Hay fever 20% Asthma ~5%. Figure 10-1. 4 types of hypersensitivity reactions. (hives). Allergies. Immune complex disease. Delayed-type hypersensitivity.

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Lecture 16 Allergy

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  1. Lecture 16 Allergy • Hay fever 20% • Asthma ~5%

  2. Figure 10-1

  3. 4 types of hypersensitivity reactions (hives) Allergies

  4. Immune complex disease Delayed-type hypersensitivity

  5. Type I hypersensitivity-mediated by mast-cell degranulation. Preformed granules contain histamine, heparin, TNF, chondroitin sulfate, neutral proteases, and other. Mucosal mast cell/Connective tissue mast cell

  6. Figure 10-4

  7. Figure 10-5 In granules Produced after activation

  8. Histamine Binds to histamine receptors: H1, H2, H3-cell-type specific Binding to H1 on: endothelial cells (increased permeability); smooth muscle (contraction); mucosal epithelium (mucus secretion)

  9. Mediators Neutral proteases activate Metalloproteases - remodeling of the extracellular matrix TNF- inflammation Lipid Mediators (PGD2, LTC4) - inflammation Chemokines (MIP-1a) - chemotaxis of leukocytes Cytokines - Production of eosinophils, Th2 cells Proteoglycans, heparin and chondroitin - sequester mediators, and effect a timed release

  10. Prostaglandins and leukotrienes PGD2- vessel dilation and permeability and chemoattractant for neutrophils LTC4- same as histamine, but 100x more potent - late response. Leukotrienes used to be called Slow Reacting Substance of Anaphylaxis - SRS-A

  11. Biologic effects of mediators

  12. Biological effects of Eosinophil mediators Late stage of an allergic response includes the recruitment of eosinophils and Th2 cells contrast with a DTH (type IV) response which includes infiltration of macrophages and Th1 cells

  13. Eosinophils

  14. Figure 10-9 part 1 of 2 Products released by eosinophils

  15. Figure 10-10

  16. Figure 10-12

  17. Figure 10-14

  18. Figure 10-16 FEV1 - the forced expiratory volume of air in one second

  19. Figure 10-18

  20. Systemic anaphylaxis

  21. Use of adrenaline to counteract the effects of system anaphylaxis In anaphylactic shock, blood vessels leak, bronchial tissues swell and blood pressure drops, causing choking and collapse. Adrenaline (epinephrine) acts quickly to constrict blood vessels, relax smooth muscles in the lungs to improve breathing, stimulate the heartbeat and help to stop swelling around the face and lips (angioedema).

  22. Asthma

  23. Figure 10-22 part 1 of 2

  24. Figure 10-22 part 2 of 2

  25. Histopathology of bronchial asthma

  26. Treatment of asthma

  27. New therapy for asthma and allergy: blocking the Fc portion of IgE from binding to the FceR on mast cells

  28. Skin test for allergy Ragweed Control Histamine

  29. Food allergies

  30. Type II hypersensitivityis caused by antibodies to altered cell-surface components

  31. Figure 10-27

  32. Type III hypersensitivity reactions (Arthus Reaction)Antibody-Antigen Complexes Critical mediators appear to be C5a-receptor and FcgRIII--probably present on mast cells

  33. Figure 10-31

  34. Figure 10-29

  35. Figure 10-32

  36. Type IV hypersensitivity - Delayed-type hypersensitivity

  37. Figure 10-34 What is missing from this scheme? Also, note time scale

  38. Figure 10-35

  39. Figure 10-36

  40. Figure 10-23

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