Immediate response: Type I Hypersensitivity Reaction
2:44
Type I hypersensitivity reaction in 2 mins!
3:16
Immune Complex-Mediated Hypersensitivity: Type III Hypersensitivity Reaction
2:10
Type 2 hypersensitivity reaction in 2 mins!
Hypersensitivity refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. They are usually referred to as an over-reaction of the immune system and these reactions may be damaging, uncomfortable, or occasionally fatal. Hypersensitivity reactions require a pre-sensitized (immune) state of the host. They are classified in four groups after the proposal of P. G. H. Gell and Robin Coombs in 1963.