Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Chapter 15 Hypersensitivity Reactions Mast cell Although the word “hypersensitivity” implies an increased response, the immune response of a hypersensitivity reaction is not necessarily heightened but instead, an inappropriate response to an antigen. Portier and Richet : Anaphylaxis 過敏反應 ↕ Prophylaxis 預防 Richet was awarded the Nobel Prize in 1913 for the discovery of anaphylaxis. Portuguese man-of-war Four Types of Hypersensitive Responses Immediate Hypersensitivity: Type I IgE-mediated hypersensitivity Type II IgG- or IgM-mediated cytotoxic hypersensitivity Type III Immune complex-mediated hypersensitivity Delayed-type Hypersensitivity: Type IV Cell-mediated hypersensitivity Type I Hypersensitivity - IgE-mediated hypersensitivity allergen (過敏原), allergic (過敏的) atopy (過敏體質), atopic (具有過敏體質的) Transfusion Reactions are Type II Reactions Hemolytic Disease of the New Born is Caused by Type II Reactions Type III Hypersensitivity Localized Type III Reaction - Arthus Reaction tissue damage Generalized Type III Reaction – Serum Sickness fever, weakness, rashes, edema, erythema, arthritis, glomerulonephritis Type IV Hypersensitivity Some populations of activated TH cells encounter certain types of antigens, they secrete cytokines that induce a localized inflammatory reaction called delayed-type hypersensitivity (DTH). The term “hypersensitivity” is misleading, since it suggests that a DTH response is detrimental. Although a DTH response can cause extensive tissue damage in some cases, DTH plays an important role in defense against intracellular pathogens . Granuloma Formation - Caused by a prolonged DTH response Contact Dermatitis Is A Type of DTH formaldehype, trinitrophenol, nickel, turpentine, detergents, poison ivy, poison oak, and active agents in various cosmetics and hair dyes Summary