Abstract
A definition of allergy is proposed, including its two stages: 1)
hypersensitivity (without clinical manifestations) and 2)
hyperreactivity with clinical signs. A specific immunologically mediated
allergy depends on the presence of antibodies of different isotypes and
immune T and B lymphocytes against an allergen. Nonspecific allergy is
hypersensitivity and hyperreactivity of the immune system and any cells,
as well as humoral systems, to the pathogen. Anergy is the second type
of pathologically altered reduced reactivity that can be of
allergen-specific (immune) and non-immune types.