Since SSc mDCs in vivo are likely to be exposed to IFN-I by the effect of the IFN-I signature often detected in these patients [1,2,5,6,19], we pretreated the MDDCs with 1000 UI/mL of IFN-α and stimulated them with CXCL4-RNA complexes for 48 h. Here, PF4 is linked to systemic sclerosis.