Induction of Th17 cells by dendritic cells

The novel T helper subset, Th17, plays a critical role in the pathogenesis of a variety of chronic inflammatory disorders such as rheumatoid arthritis, Crohn's disease, and others. Although inflammatory dendritic cells (DCs), such as DCs producing TNFα and iNOS, have been suggested to act as an inducer of Th17-immunity both in humans and mice in vivo; it is unclear how DCs elicit Th17-immunity. Recently, some Th17-differentiation pathways, both TGF-β-dependent and -independent pathways, have been identified in mice. However, the DC biology to evoke Th17-immunity in chronic inflammation or autoimmunity has not yet been clarified, in particular, in human cells. This review summarizes and discusses the induction of Th17 cells by DCs.