Discovery of Autoantibodies Associated with Psoriatic Arthritis

Abstract

Abstract Objective The autoimmune etiology in psoriasis is not very clear, we aim to identify autoantigens and autoantibodies in psoriasis, which may shed light on the molecular and cellular basis of the pathogenesis of psoriasis and psoriatic arthritis. Methods In this study, we developed an autoantigen array system harboring a variety of antigens including typical autoantigens in rheumatic diseases as well as skin antigens, inflammatory mediators and putative autoantigens in psoriasis. Sera from psoriasis patients (N = 73) were used to interrogate antigens on the array. Individual ELISA was also used in validation studies. Results We found several serum autoantibodies were elevated in psoriasis patients compared to healthy controls; particularly, IgG autoantibodies against two novel antigens, LL37 and ADAMTSL5, were significantly increased in the psoriasis patients compared to healthy controls. Importantly, serum levels of IgG autoantibodies against LL37 and ADAMTSL5 were correlated with Psoriasis Area and Severity Index (PASI), and reflected disease progression in longitudinally collected samples from psoriasis patients. Importantly, we found both anti-ADAMTSL5 and anti-LL-37 autoantibodies were significantly elevated in psoriatic arthritis (PsA) compared to Non-PsA, suggesting that these molecules may be involved in the pathogenesis of psoriatic arthritis. Conclusion Our findings suggest that these autoantibodies may be useful biomarkers and indicative of therapeutic targets of psoriasis and psoriatic arthritis.