Hypersensitivity

Hypersensitivity (also called hypersensitivity reaction) is an immune response characterized by mechanisms that cause significant tissue damage or physiological dysfunction, whether directed against pathogens, harmless environmental antigens, or self-antigens that is reproducible upon re-exposure to the antigen. While hypersensitivity mechanisms can sometimes serve protective functions (such as control of infectious diseases), they are distinguished by their capacity to cause collateral tissue damage that may exceed any protective benefit. Collectively, hypersensitivities are extremely common:

inflammatory response driven by T cell recognition of processed soluble or cell-associated antigens, leading to cytokine release and leukocyte activation

inflammatory response resulting in cell death or dysfunction

human disease