CCL2 and interstitial lung disease: Additional research has highlighted a panel of serum biomarkers linked to more severe fibrotic trajectories in SSc-ILD, including lower levels of fractional exhaled nitric oxide and interleukin (IL)-10, along with elevated concentrations of carbohydrate antigen 15.3 (CA15-3), C-reactive protein (CRP), and monocyte chemoattractant protein-1 (MCP-1) [54].