F2R and systemic sclerosis: Antibodies against protease-activated receptor-1 (PAR-1), a GPCR with key roles in regulating the interplay between coagulation and inflammation, have been detected in SSc patients with SRC, where they agonistically activate PAR-1 and engage a signaling cascade that finally induces IL-6 production by endothelial cells [3,4,97].