As reviewed by Ganesan and Rasool [56], high expression of TNF-α, IL-1β, IL-6, IL-8, IL-15, vascular cell adhesion molecule-1 (VCAM-1), thrombospondin-1 (TSP-1), and stromal cell-derived factor-1 (SDF-1) have been reported in FLS of RA patients. Here, IL15 is linked to rheumatoid arthritis.