Type IV Hypersensitivity: Pathogenesis and clinical ...
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Description

Type IV Hypersensitivity: Pathogenesis and clinical findings

Definition: Unique because it is entirely T-Cell mediated; exposure to allergen causes development of allergen-specific T-Cell response. Allergic reaction develops several days after exposure, because T-Cell activation takes time.

Initial exposure to allergen (typically a drug)

-> Macrophage engulfs antigen

-> Antigen presentation on MHC II molecule

-> Particular CD4+ Th cells recognize antigen on allergen's surface as potentially harmful

-> Th Cells activate macrophages, mast cells or CTLs

-> Inflammation and destruction of involved issue

=> 

 • Stevens-Johnson Syndrome

 • Contact Dermatitis (Ex. Poison ivy)



#TypeIV #Type4 #HypersensitivityReaction #Allergy #Immunology #pathophysiology 
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The Calgary Guide to Understanding Disease
@TheCalgaryGuide
Account created for The Calgary Guide to Understanding Disease - Linking pathophysiology to clinical presentation - http://calgaryguide.ucalgary.ca/
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