PDGFA and idiopathic pulmonary fibrosis: A correlation was observed between PDGFA and the radiological pattern on HRCT in patients with RA-ILD, as evidenced by significantly lower gene expression in patients with usual interstitial pneumonia (UIP), probably UIP or indeterminate for UIP pattern than in those with a radiological pattern of non-specific interstitial pneumonia (NSIP) or non-NSIP (0.