PF4 and systemic sclerosis: In SSc a dysregulation of some angiogenic factors, such as VEGF, fibroblast growth factor-2 (FGF-2), PDGF, TGF-β, monocyte chemoattractant protein-1 (MCP-1), stromal cell-derived factor 1 (SDF-1/CXCL12), interleukin (IL)-8, ET-1, and urokinase type plasminogen activator receptors (uPAR), and some antiangiogenic factors, such as angiostatin, thrombospondin-1 (TSP-1), endostatin, platelet factor 4 (PF4/CXCL4), IL-4, and pentraxin 3 (PTX3), has been described (Table 1) [10, 11, 30–36].