CXCR4 and systemic sclerosis: IL-17 A derived from the serum of SSc patients has been shown to induce the expression of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), as well as C-C motif chemokine ligand 20 (CCL-20) and C-X-C motif chemokine receptor 4 (CXCR-4) in endothelial cells, leading to endothelial inflammation6,24.