ROC curve analysis confirmed that the assessment of PDGFA, TGFB1, and TGFB2 expression effectively differentiated between RA-ILD and RA-nonILD patients, acting as biomarkers for the early detection of ILD in RA (AUC: 0.7345, p = 0.0040, AUC: 0.7300, p = 0.0041, AUC: 0.8021, p = 0.0002, respectively, Figure 3A, Table S1). This evidence concerns the gene PDGFA and interstitial lung disease.