A new player in psoriatic arthritis: a JAK inhibitor

Abstract

Psoriatic arthritis (PsA) is an inflammatory arthritis in patients with psoriasis (Pso). Pso affects 2-4% of the general population while PsA affects 65% of Pso patients if one uses even regional imaging modalities.1,2 PsA can involve peripheral joints and spinal joints, causing oligoarticular or polyarticular arthritis and spondyloarthropathy, but also affects various tissues causing enthesitis, dactylitis, and uveitis. A radiographic characteristic of PsA, not found in rheumatoid arthritis (RA), is that it can cause bone erosions and bone formation at various joint sites. The pathogenesis of the disease is incompletely understood. Nevertheless, inflammatory cytokines, such as interleukin (IL)-12, IL-17, interferon (IFN)γ, IL-23, and IL-22, and cells of the adaptive immunity and innate immunity are implicated. Moreover, the elevated cytokines of the IL-23/IL-17 axis with IL-17 and IL-22 of the axis having erosive and bone-forming actions, respectively, suggest that PsA and psoriasis may be the same disease.3 © This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.