PF4 and systemic sclerosis: Since CXCL4 is highly up-regulated in eaSSc (especially in the diffuse form [7]), as well as in VEDOSS [30], one could speculate that the initial production of autoantibodies to CXCL4 could serve to neutralize CXCL4 excess, which may also block excess of IFN-I production at the beginning of the SSc symptoms.