Figure 1

Potential strategies to regulate the IL-17 pathway for the treatment of asthma. T-helper 17 (Th17) cells are differentiated under the control of interleukin (IL)-6, transforming growth factor (TGF)-β, and IL-23. IL-17 produced predominantly by Th17 cells augments allergic airway inflammation by inducing the expression of various pro-inflammatory mediators such as cytokines, chemokines, and adhesion molecules, in turn leading to recruitment and activation of neutrophils and Th2-mediated eosinophils. The modulation of cytokines or transcription factors, inhibition of kinases, phosphodiesterase 4 (PDE4), vascular endothelial growth factor (VEGF), and pharmacological agents such as statins, steroids, and resolvin E1 down-regulate IL-17 expression, thus ameliorating allergic airway inflammation.