In vitro stimulation of RA synovial fibroblasts with IL-18 increased the production of the chemokines IL-8/CXCL8, epithelial-neutrophil activating protein/CXCL5, growth-regulated oncogene α (GROα)/CXCL1, and the CC chemokine; CCL2 [118] as well as the angiogenic factors stromal cell-derived factor 1α (SDF-1α/CXCL12) and vascular endothelial growth factor A (VEGF-A) [119]. Here, CXCL12 is linked to rheumatoid arthritis.