PF4 and systemic sclerosis: One of the effector functions of these anti-CXCL4 autoantibodies could be to concentrate and more efficiently deliver CXCL4–DNA/RNA complexes to immune cells, such as pDCs, to further amplify IFN-α production in SSc and the secretion of inflammatory factors, such as TNF-α or IL-12/IL-23 [41].