Lee et al. suggested that the alleviations of PF animals and IPF people after i.v. injection of MSCs in the tail were caused by MSCs activation to secrete TNF-α-stimulated gene/protein 6 (TSG-6), which is an significant anti-inflammatory gene and expressed in various kinds of cells [47, 123]. This evidence concerns the gene TNFAIP6 and idiopathic interstitial pneumonia.