Targeting T-helper 9 cells and interleukin-9 in autoimmune diseases.

CD4(+) T helper (Th) cells are central to the modulation of immune responses, with distinct effector subsets defined by their lineage-specific transcription factor expression, cytokines production and immune function. Th9, one of the recently defined subsets of Th cells, are identified by the potent production of interleukin-9 (IL-9). Recent studies have indicated that Th9 cells and IL-9 are closely associated with several autoimmune diseases, such as systemic lupus erythematosus (SLE), experimental autoimmune encephalitis (EAE) and systemic sclerosis (SSc). In the present review, we will briefly discuss the biological features of Th9/IL-9 and summarize recent advances focusing on the role of Th9/IL-9 in the pathogenesis and possible treatment in autoimmune diseases using anti-Th9 target.