PF4 and systemic sclerosis: Anti-CXCL4/CXCL4-L1 autoantibodies were measured also in a replication VEDOSS cohort (Figure S4): The results obtained offered a similar picture, with no significant differences in SSc-progressors, (n = 15) versus SSc-non-progressors, (n = 33), with respect to the antibody reactivity to CXCL4/CXCL4-L1 (Figure 4b).