COL1A2 and idiopathic pulmonary fibrosis: There was no significant difference in the expression of type I procollagen in fibroblasts among idiopathic UIP, CVD-associated UIP and idiopathic NSIP, while that in type II pneumocytes in patients with idiopathic UIP was significantly higher than in idiopathic NSIP (P < 0.01, Fig. 2C).