PDGF-D, PDGF-Rβ and smooth muscle actin in transplant arteriopathy. A: PDGF-D is expressed by medial smooth muscle cells, neointimal smooth muscle cells and some adventitial cells. B: In a serial section, PDGF-Rβ is expressed in a similar pattern by medial smooth muscle cells and neointimal smooth muscle cells. In addition, extravascular interstitial and adventitial cells strongly express PDGF-Rβ. C: Alpha smooth muscle actin immunolabeling of a serial section demonstrates a pattern of expression similar to PDGF-D, with strong staining of medial smooth muscle cells, neointimal smooth muscle cells and some adventitial cells and indicates co-localization of PDGF-D to these cells. Expression by interstitial myofibroblasts is also seen (*), which lack PDGF-D co-localization. G: glomerulus Original magnification A-C, ×200.