SELECTED ARTICLES FROM THE RECENT LITERATURE 2007

10/9/07

Sublingual immunotherapy induces IL-10-producing T regulatory cells, allergen-specific T-cell tolerance, and immune deviation

Summary
Sublingual immunotherapy (SLIT) is gaining rapid acceptance in Europe and being evaluated for release in the United States. Although clinical studies offer ample evidence (albeit not unanimous) of its effectiveness, there is a paucity of information regarding its mechanism of action.

The Viennese investigators conducting this study sought to elucidate the potential mechanisms of action of SLIT. They evaluated nine patients before and after four weeks, and after 52 weeks of SLIT. Birch pollen allergen was used for this treatment.

Their findings were somewhat similar to those which have been demonstrated for subcutaneous immunotherapy. They found that SLIT, after four weeks of treatment, induced increased numbers of FoxP3 and IL-10, while reducing IL-4 and interferon gamma messenger RNA expression. There was prolonged suppression of peripheral blood mononuclear cell proliferation to Bet v 1. Also, after 52 weeks, in parallel to the suppression of Bet v 1-induced proliferation, there was increased interferon gamma and reduced IL-4, IL-10, and FoxP3 messenger RNA expression.

The authors concluded that SLIT induced regulatory T cell suppression via IL-10 in the early phase, and specific non-reactivity and immune deviation of allergen-specific T cells during the later phase of therapy.

Reference
Bohle B, Kinaciyan T, Gerstmayr M, et al., Journal of Allergy and Clinical Immunology 2007; 120:707-713.

Editor's Comments
The changes induced by SLIT in this investigation were reminiscent of those which have been detected during subcutaneous immunotherapy. Thus there may be a common mechanism of action occurring during the administration of allergens resulting in relief of symptoms regardless of the route of administration.

 

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