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What is Granuloma formation is seen with which hypersensitivity reaction? and explain in detail?
Ans d: (Ref: ROBBINS 7th edition- 217)Cell mediated or Delayed type hypersensitivity Involve activated T cells. It includes:a) Delayed hypersensitivityMajor mechanism of defense against various intracellular pathogens Characteristic lesion is granuloma -Activated macrophages(epitheliod cells) surrounded by a collar of lymphocytes & giant cellsb) T cell mediated cytotoxicityMechanism: Cytotoxic T cells kill virus infected cells of tumor cells Eg of Type IV HS* Tuberculin test, lepromin test, Frei test, Fairley's test* Typel lepra reaction* Contact dermatitis* Temporal arteritis* Jones mote reaction( cutaneous basophilic HSN)