Interleukin-35: A Serological Biomarker for Patients with Polymyositis/Dermatomyositis.

Interleukin (IL)-35 is confirmed as an important modulator in immune response. The aim of the study was to explore the role of IL-35 in the development of polymyositis/dermatomyositis (PM/DM). Ninety-five patients with PM/DM and 30 healthy controls (HCs) were recruited. Peripheral blood mononuclear cells (PBMCs) were isolated by Ficoll-Paque Plus density gradient centrifugation. Protein IL-35, IL-17, and tumor necrosis factor (TNF)-α levels were measured using enzyme-linked immunosorbent assay method. The IL-35 serum levels in PM/DM patients were significantly higher than those in HCs and were correlated with PM/DM-related features: disease activity, muscle damage, and interstitial lung disease (ILD). Exogenous IL-35 notably suppressed lipopolysaccharide-induced IL-17 and TNF-α production in PBMCs of patients with PM/DM. Elevated serum IL-35 levels could act as a disease activity biomarker and an indicator of ILD in PM/DM. IL-35 may play an anti-inflammatory role in PM/DM.