16: Hypersensitivities
- Page ID
- 3335
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Hypersensitivities are a set of undesirable reactions produced by the normal immune system, including allergies and autoimmunity. These reactions may be damaging, uncomfortable, or occasionally fatal. Hypersensitivity reactions require a pre-sensitized (immune) state of the host. Immediate hypersensitivities refer to humoral immunity (antigen/antibody reactions) causing harm. Delayed hypersensitivities refer to cell-mediated immunity (cytotoxic T-lymphocytes, macrophages, and cytokines) leading to harm.