Targeting cytokines in psoriatic arthritis.

Psoriatic arthritis (PsA) is part of the psoriatic disease spectrum and is characterized by a chronic inflammatory process that affects entheses, tendons and joints. Cytokines produced by immune and non-immune cells play a central role in the pathogenesis of PsA by orchestrating key aspects of the inflammatory response. Pro-inflammatory cytokines such as TNF, IL-23 and IL-17 have been shown to regulate the initiation and progression of PsA, ultimately leading to the destruction of the architecture of the local tissues such as soft tissue, cartilage and bone. The important role of cytokines in PsA has been underscored by the clinical success of antibodies that neutralize their function. In addition to biologic agents targeting individual pro-inflammatory cytokines, signaling inhibitors that block multiple cytokines simultaneously such as JAK inhibitors have been approved for PsA therapy. In this review, we will focus on our current understanding of the role of cytokines in the disease process of PsA and discuss potential new treatment options based on modulation of cytokine function.