Role of IL-17 in allergic airway inflammation

The identification of novel helper T (Th) cell subsets, "IL-17-producing Th cells (Th17 cells)", provided new insight into our understanding of the molecular mechanisms for host defense and the development of autoimmune diseases, and thus led to revision of the classic ThI/Th2 paradigm. Several current lines of evidence from gene-deficient mice indicate that IL-17 and Th17 cells, but not IFN-gamma and Thl cells, are important for the development of autoimmune diseases such as murine arthritis and encephalomyelitis, which have classically been considered to be Thl-mediated disorders. Several current lines of evidence indicate that Th17 cells may also contribute to the pathogenesis of Th2-mediated allergic reactions, forcing us to change our understanding of the classic pathogenic mechanisms of allergic diseases. In this session, we summarize the current knowledge regarding IL-17 and Th 17 cells and discuss their potential roles in the pathogenesis of allergic disorders.