Type I hypersensitivity in which a person's body is hypersensitised and develops IgE type antibodies to typical proteins. When a person is hypersensitised, these substances are known as allergens. The word allergy derives from the Greek words allos meaning "other" and ergon meaning "work". Type I hypersensitivity is characterised by excessive activation of mast cells and basophils by [immunoglobulin E]? resulting in a systemic inflammatory response that can result in symptoms as benign as a runny nose, to life-threatening anaphylactic shock and death.