Immunohistochemical analysis of lung tissue of IPF patients showed an association between TIMP-2 antigen and fibroblasts, whereas TIMP-1 antigen was present in interstitial macrophages and TIMP-3 and -4 antigens were confined to the epithelium (Selman et al., 2000; Garcia-Alvarez et al., 2006). Here, TIMP3 is linked to idiopathic pulmonary fibrosis.