Mechanism of Regulatory T Cells During Allergen-Specific Immunotherapy: from the Past to Future

Since the first trial reported by Noon about a century ago [1], allergen-specific immunotherapy (SIT) by repeated subcutaneous administration of increased doses of allergen extracts has a long-lasting effect on immunologic tolerance to common environmental allergens [2-4]. Allergen-specific subcutaneous immunotherapy (SCIT) has been effectively used for the treatment choice for allergic rhinitis and asthma [5,6]. It is clear that SCIT reduces the symptoms of allergic disease and can alter the natural course of allergic disease, however, the basic immunologic mechanisms involved in the amelioration of the allergic symptoms are becoming better understanding in recent years.