CXCL8 and rheumatoid arthritis: All of these upregulated proteins have previously been reported in RA (IL–8 (9), CCL20 (9), IL–18 (10), IL–10RB (11), OPG (12), 4E–BP1 (13), HGF (14) and caspase 8 (15)); however, these proteins were reported in relationship with GC therapy in other pathologies/conditions, but not in RA.