CXCL12 and idiopathic pulmonary fibrosis: In addition, confocal analysis confirmed that SDF-1 colocalized with MMP19, and SDF-1-positive staining was significantly stronger in the endothelial cells of MMP19WT- and MMP19E213A-AAV-infected mice and IPF lungs compared to that in the corresponding control lung (Fig. 6G).