The CCL8 mRNA level normalized to that of β-actin was 3-fold higher in the IPF fibroblasts than in the control fibroblasts by RT-PCR (p = 0.0001; Fig. 2a and b) and real-time PCR (p = 0.022; Fig. 2c). Here, ACTB is linked to idiopathic pulmonary fibrosis.