RETN and juvenile idiopathic arthritis: The treatment of peripheral mononuclear cells isolated from healthy donors with serum from JIA patients in remission promoted an increase in the levels of inflammatory mediators (TNF-α, IL-1β, IL-6, IL-8 and IFN-γ), oxidative stress markers (SOD-1 and SOD-2) and adipokines (visfatin and resistin) compared to the treatment with serum from healthy donors (Fig. 4a-c).