IFNA1 and systemic sclerosis: SSc subtype analysis confirmed correlations between IFN-α and anti-CXCL4 antibody reactivity in the replication cohort (SSc2); of note in this cohort, as reported in Figure 1, anti-CXCL4 antibody reactivity was significant also in the early diffuse subgroup and not only in the diffuse long-lasting group.