, Volume 1, Issue 1, pp 1-13

Mechanisms of Allergen-Specific Sublingual Immunotherapy and the Use of Biological Markers in Allergic Rhinitis

Opinion statement

Clinical and immunologic tolerance are hallmarks of successful allergen sublingual immunotherapy (SLIT) in carefully selected patients. Clinical benefit such as reduced symptoms, pharmacotherapy intake, and improvement of quality of life persists following discontinuation of treatment. Successful SLIT is associated with suppression of allergic inflammatory cells such as mast cells, eosinophils, and basophils. Furthermore, SLIT immunomodulates allergen-specific Th2 responses in the tissue (target organ) and the periphery. The immunologic tolerant state induced following SLIT is associated with induction of allergen-specific IL-10+, TGF-β+, and FoxP3+ regulatory memory T cells. B cell responses, in particular IgG4-associated blocking antibodies and IL-10+ regulatory B cells, are also induced following allergen immunotherapy (AIT). These events are followed by suppression of allergen-specific proliferation Th2 responses and result in immune deviation from a T helper 2-type to T helper 1-type response. Despite insight gained with regard to the mechanisms of SLIT, to date there are no validated biomarkers that are predictive of the clinical response to treatment. This review reports recent advances in understanding mechanisms of SLIT and outlines relevant potential biomarkers for monitoring allergen-specific immunotherapy.