CCN2 and idiopathic pulmonary fibrosis: The mean serum CTGF concentrations in the subgroups were as follows: IPF, 538.43±469.82 ng/L; iNSIP, 667.87±629.05 ng/L; CTD-ILD, 393.25±100.27 ng/L; sarcoidosis, 301.52±171.98 ng/L; and silicosis, 403.30±204.40 ng/L (Figure 1).