Interestingly, re-analysis of the microarray data from IPF human lungs (GSE72073) and lung fibroblasts (GSE40839)15 showed that among the 21 members of human PDI, only TXNDC5 and CASQ2 were significantly upregulated in human IPF, compared to control, lung tissue (Supplemental Fig. 13a). Here, P4HB is linked to idiopathic pulmonary fibrosis.