This study aims to detect serum levels of monocyte chemoattractant protein-1 (MPC-1) and transforming growth factor-β1 (TGF-β1) in polymyositis/dermatomyositis (PM/DM) patients complicated with interstitial lung disease (ILD), to reveal the significance of the changes in these levels in the pathogenesis of PM/DM complicated with ILD. Here, MPC1 is linked to diabetes mellitus.