CCL2 and diabetes mellitus: Serum MCP-1 and TGF-β1 levels in PM/DM patients complicated with ILD, patients with pulmonary infections and normal controls (n = 30, each) were detected using enzyme-linked immunosorbent assay (ELISA), and the correlation between PM/DM complicated with ILD and serum MCP-1 and TGF-β1 levels was analyzed.