Immunological mechanisms of sublingual immunotherapy

PURPOSE OF REVIEW: This review aims to recap recent published data on immunological mechanisms underlying sublingual immunotherapy (SLIT). RECENT FINDINGS: Although several alternative noninvasive allergen application strategies have been investigated in allergen-specific immunotherapy, local intraoral allergen application to sublingual mucosa has been proven to be safe and effective. To date, SLIT is widely accepted by most allergists, especially in Europe as an alternative to subcutaneous immunotherapy. Within the recent decades, much scientific effort focused on local and systemic immunological responses to SLIT in mice as well as humans. Among these studies, several investigated detailed mechanisms following allergen application to the oral mucosa as part of the sophisticated mucosal immunological network in which the protolerogenic character of local antigen-presenting cells such as dendritic cells play a central role. Moreover, immune responses to SLIT have also been studied in nasal and bronchial mucosa as well as on the systemic T cell immune alterations. SUMMARY: Altogether, exiting data have been published providing a better understanding of immunological features of SLIT but far more basic research is necessary to further uncover key mechanisms of SLIT.