Specific antigen immunotherapy (SIT) is the process of administering increasing doses of an allergen to which the patient has demonstrated sensitivity. The process has been variously referred to as allergy desensitization, hyposensitization, or simply “allergy shots.” This procedure is one of three major categories of accepted therapy for IgE-mediated inhalant allergy. The other modalities are environmental control and medical therapy.

The purpose of this therapy is to ameliorate the symptoms of inhalant allergy by decreasing the reactivity of the patient to the specific antigen. This clinical intervention has been used empirically for over 80 years, since its introduction by Noon in 1911.<sup>18 Noon L. Prophylactic inoculation against hay fever Lancet 1911 ;  1 : 1572  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup> Although initial treatments were performed based upon clinical success, scholarly works in recent decades have provided double-blinded studies documenting the benefits of immunotherapy. Several mechanisms of action have been suggested for the immunotherapy process, but it remains unclear which pathway exerts the predominant beneficial effect upon the patient.