The Role of IL-17 Cytokines in Psoriasis.

Psoriasis is a chronic inflammatory skin condition associated with immune dysregulation. The immunologic cascade mediated by the interleukin (IL)-17 pathway plays a critically important role in the pathogenesis of psoriasis. The IL-17 effectors (IL-17A, IL-17C, IL-17E, and IL17F) act on keratinocytes, endothelial cells, and immune cells to stimulate epidermal hyperplasia and the pro-inflammatory feed-forward cycle seen within plaque psoriasis. The IL-17 pathway is also hypothesized to modulate the inflammatory responses linking comorbid systemic diseases with psoriasis. Furthermore, the robust clinical response seen with current and emerging therapies targeting IL-17 emphasizes the importance of the IL-17 cytokines in the pathogenesis of psoriasis.