A previous study investigated the serum level of inflammatory mediators and revealed that inflammatory cytokines, such as IL-8 and sTNFR, and substance P were significantly increased in CRPS type I patients compared to the controls, but adhesion molecules, such as E-selectin, L-selectin, and P-selectin, decreased in CRPS patients [47]. This evidence concerns the gene CXCL8 and complex regional pain syndrome.