Recently, when measuring circulating levels of CXCL4, CXCL8, and GDF15, a small chemokine belonging to the TGF-β superfamily, in another cohort of SSc patients, only GDF15 was found to be higher in SSc and to associate with PAH and dilated capillary loops at capillaroscopy [191]. This evidence concerns the gene PF4 and systemic sclerosis.