ABSTRACT
I. INTRODUCTION Allergen immunotherapy has been practiced in the United States since its original description by Noon and Freeman in 1911 for the treatment of allergic symptoms due to inhalant allergens (1). In 1918, Dr. Robert Cooke suggested a mechanism of action for allergen injections as a "desensitization or hyposensitization." The more specific immunological basis for allergic disease was initially established by Prausnitz and Kustner, who demonstrated that the allergic sensitivity could be transferred by the serum of a sensitive person to the skin of a nonallergic person (2). Allergen immunotherapy is defined as the repeated administration of specific allergens to patients with IgE-mediated conditions for the purpose of providing protection against the allergic symptoms and inflammatory reactions associated with natural exposure to these allergens (3). The technique of allergen immunotherapy should be differentiated from the process of desensitization, which is the term applied to the rapid, progressive administration of an allergenic substance, usually a drug, to render effector cells less reactive.
