CCN2 and idiopathic interstitial pneumonia: In PF-ILD (IPF+F-ILDs) patients, CTGF serum levels showed a significant increase from baseline to the 12-month follow-up, predominantly driven by patients in the IPF subgroup, as no significant changes were observed in the other subgroups (iNSIP, CTD-ILD, sarcoidosis, or silicosis).