PF4 and systemic sclerosis: Only one study addressed the effect of prostaglandin E2 on IFN-I secretion by pDCs stimulated with synthetic TLR9 agonists [32], whereas the role of iloprost as a disease-modifying drug in early SSc patients, together with its capacity to modulate the inflammatory axis CXCL4-IFN-I in vivo and in vitro, is still largely unknown.