Immunologic advances reveal new targets in psoriasis and psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory joint disorder with heterogeneous clinical features that may include plaque psoriasis, joint inflammation, enthesitis, dactylitis, and abnormal bone turn over. This disease is common, affecting up to 0.5% of the population with equal male and female prevalence. Until recently, few treatment options were available for PsA and patients suffered immense physical and social burden. Traditional disease modifying agents show limited efficacy in the treatment of PsA. Anti-tumor necrosis factor (TNF) drugs are effective for all the manifestations, yet recent studies show that up to 50% of patients either do not tolerate these medications or do not maintain a clinical response. The evolution in the treatment of PsA emerged from improved understanding of the pathophysiology of the disease with Th1 and Th17 cells taking center stage. Targeting TNF along with cytokines in the IL-23/TH17 pathway (IL-23, IL-17, and IL-22) holds great promise for improved treatment outcomes in PsA.