Mechanisms of allergen specific immunotherapy

Abstract

Summary Clinical efficacy of specific immunotherapy (SIT) in the treatment of respiratory allergic diseases as well as venom allergy has been demonstrated in various well-controlled studies. However the precise mechanisms of SIT have not been well defined, and for more than twenty years now, research on immunological markers of efficacy of SIT raised many theories on the mechanism of SIT. Recently, the use of molecular genetic techniques constituted a «breakthrough in the comprehension of the immunomodulatory effects of SITsince it has been demonstrated clearly that SIT induces a shift in the Th2/ Th1 balance. At the first stage there is a desensitization of effector cells like basophils, mast cells and eosinophils leading to a reduction of inflammatory mediators release. Simultaneously T lymphocytes and antigen-presenting cells are committed to the production of Th1-type cytokines although Th2-type cytokines are damped. This result in the modification of allergen-specific IgE and IgG4 production pattern and an inhibition of effector-cells migration and activation.