[The immunological mechanisms contributing to the clinical efficacy of allergen specific immunotherapy (SIT) in allergic diseases].

The prevalence of allergic diseases has increased dramatically in the western world. In the last 2 decades, the frequency of asthma and allergic rhinitis has doubled. Allergen specific immunotherapy [SIT] has been used successfully for more than 100 years for the treatment of allergic disorders. Allergen SIT provides not only symptomatic relief, but it is potentially curative. The immunologic mechanisms of allergen SIT include all parts of the immune system. Regulatory T cells (TR1, Treg), have a major pivotal role in the success of immunotherapy. Along with the regulatory T cells, elevated suppressor cytokines (IL-10), suppression of TH2 cells, increasing titer of specific IgG4 and gradual decline in the number and function of basophils and mast cells also contribute to the success of the treatment (SIT). The above immune mechanisms are connected and related to each other acting at different times with the treatment with SIT. In this review we focused on the current knowledge and understanding of the different immune mechanisms which are involved in the success of SIT.