PF4 and systemic sclerosis: These findings reinforce the role of CXCL4 and CXCL4-RNA complexes in the induction of the IFN-I signature in SSc, in addition to the role of CXCL4-DNA complexes [6], and extend the recognition of the effect of the CXCL4-RNA complexes in the activation of mDCs, which are crucial in immunity.