Abstract

Rhinitis or asthma or both occur in some people because a specific reaginic antibody (IgE) develops after exposure to a particular allergen, for example house dust or grass pollen, and becomes attached to the surface of mast cells in nasal and bronchial tissue. Subsequent exposure of these tissue sites to the allergen and consequent interaction of allergen and reaginic antibody on the surface of mast cells results in their disruption with release of various substances which act on blood vessels and plain muscle and so cause the symptoms of asthma or rhinitis. Injections of successively increasing concentrations of the allergen (hyposensitisation) are widely used to treat these conditions. Where such treatment is effective it is suggested that the injections increase the plasma concentrations of ‘blocking’ antibody (IgG) specific for this allergen, so mopping up allergen that enters the body later and ‘blocking’ the union of allergen and IgE on the surface of mast cells, thus preventing the damaging reactions.