CXCL8 and rheumatoid arthritis: In a previous study, we could demonstrate that the number of synovial fibroblasts positive for DR was significantly higher in RA compared to osteoarthritis (OA) patients, and the activation of DR via dopamine led to a reduction of IL-6 and IL-8 release from synovial fibroblasts in RA patients not treated with any disease modifying anti-rheumatic drug (DMARD) (Capellino et al. 2014).