Figure 1

Plateled-derived growth factor receptor (PDGFR)-β immunoreactivity in pulmonary vessels in SScPAH, IPAH and PVOD. (Original magnification 200×). A) PDGFR-β immunoreactivity in the endothelial layer of a small corner vessel without fibrosis in SScPAH. Note the epithelial immunoreactivity at the alveolar attachments of the corner vessel, serving as an internal positive control. B) PDGFR-β immunoreactivity in the endothelium of a small corner vessel with fibrosis in SScPAH, and in the (congested) capillary endothelium. C) Absence of PDGFR-β immunoreactivity in the endothelial layer of a small corner vessel with intimal fibrosis, in an area of capillary congestion, in PVOD. There is epithelial immunoreactivity at the alveolar attachments of the corner vessel. D) PDGFR-β immunoreactivity in endothelial cells of capillaries in a SScPAH patient. E) Intense PDGFR-β endothelial immunoreactivity in an area of congestion in a PVOD patient. F) PDGFR-β endothelial immunoreactivity in a vein in a SScPAH patient. G) PDGFR-β immunoreactivity in the basal side of the endothelium of an arteriole with intimal fibrosis and media hyperplasia in an IPAH patient. H) PDGFR-β immunoreactivity in a plexiform lesion in an IPAH patient; immunoreactivity of basal side of the endothelial cells (insert) in the glomeruloid lesion, surrounded by vein-like branches (dilatation lesions).