Dendritic cells as potential targets for mucosal immunotherapy.
OBJECTIVE
A recent meta-analysis confirmed that sublingual immunotherapy represents a safe and efficient alternative to traditional subcutaneous immunotherapy in the treatment of allergic rhinitis. However, the immunological mechanisms have not been elucidated in detail yet. The current concept postulates a Th2/Th1 shift along with tolerance induction. Without doubt, oral mucosal antigen-presenting cells such as dendritic cells play a central role as they process antigens to initialize and modulate T-cell activation.


RESULTS
Oral mucosal dendritic cells (oDCs) are capable of processing antigen applied on mucosal surfaces. The natural pro-tolerogenic character of oDCs has been demonstrated by the induction of tolerogenic T cells in response to oDCs activated by either externally applied antigens such as ovalbumin or antigens originating from commensal bacteria like Toll-like receptor ligands, which have been shown to be promising candidates for adjuvants. Nevertheless, the finding of relatively low numbers of oDCs within the sublingual region opens the search for different allergen application sites within the oral cavity such as the vestibular region where higher numbers of oDCs are detectable.


CONCLUSIONS
oDCs display a natural pro-tolerogenic character, which is suspected to be essential for successful sublingual immunotherapy. Further knowledge about oDCs behaviour might give rise to new sublingual immunotherapy strategies such as adjuvant supplementation.
Allam
Jean-Pierre
JP
Department of Dermatology and Allergy, University of Bonn, Bonn, Germany.
Bieber
Thomas
T
Novak
Natalija
N
D000485:Allergens / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology; D000818:Animals; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology*; D003888:Desensitization, Immunologic; D004333:Drug Administration Routes; D006801:Humans; D007108:Immune Tolerance; D056747:Immunomodulation; D009061:Mouth Mucosa / Q000473:pathology; D012221:Rhinitis, Allergic, Perennial / Q000276:immunology / Q000628:therapy*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology / Q000628:therapy*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
D000485:Allergens