An update on biomarker discovery and use in systemic sclerosis.

INTRODUCTION: Systemic sclerosis (SSc) is an autoimmune disease characterized by excessive extracellular matrix deposition in the skin and internal organs. Three major abnormalities, autoimmunity, vasculopathy, and fibrosis, are considered to play important roles in the pathophysiology of SSc. SSc is a heterogeneous disease with clinical features, disease progress, therapeutic response, and prognosis. Therefore, identification of biomarkers, which can predict the course of the disease, is required for the progress of clinical practice. Areas covered: This review focuses on various SSc biomarkers for diagnosis, disease severity, and activity, as well as newly emerging and promising SSc biomarkers. Search was through PubMed and we focus on the papers in the last 5 years. Expert commentary: Biomarkers for SSc can be categorized into several groups: activity biomarker, severity biomarker, predictive biomarker, and biomarkers for specific clinical features (skin fibrosis, lung fibrosis, pulmonary arterial hypertension, peripheral vasculopathy, gastrointestinal, and malignancy). Some chemokines, such as CCL2 and CXCL4, have been identified as biomarkers of skin and lung fibrosis in SSc. In addition, anti-RNA polymerase III antibody has been noted to be a predictive biomarker of gastric antral vascular ectasia and malignancy.