Elhai M, et al. - In this investigation, researchers evaluated the diagnostic and prognostic performance of 4 candidate serum biomarkers for systemic sclerosis (SSc)-associated interstitial lung disease (ILD). For this investigation, they analyzed serum samples from a combined cohort of 427 SSc patients by enzyme-linked immunosorbent assay for concentrations of lung epithelial–derived surfactant protein D (SP-D), Krebs von den Lungen 6 glycoprotein (KL-6), CCL18, and OX40 ligand (OX40L). In baseline SSc patients, KL-6 serum levels correlated with forced vital capacity (FVC), carbon monoxide diffusion capacity, and lung fibrosis extent. Serum levels of KL-6 and SP-D, but not CCL18 and OX40L, have been associated with lung fibrosis in multivariate analyses. Overall, the investigators suggested that SP-D is a relevant diagnostic biomarker for SSc-associated ILD, while KL-6 may be used to assess lung fibrosis severity. CCL18 seems to be a potential predictive marker in SSc for ILD progression.