SSc-related peripheral vascular features have also been evaluated in relation to circulating angiogenic T cells (Tang), a specific T cell population found to induce new blood vessel formation and repair and characterized by the co-expression of CD3, CD31, and CXCR4 (i.e., the receptor for the CXC chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12) [55,56]. This evidence concerns the gene PECAM1 and systemic sclerosis.