IL15 and rheumatoid arthritis: Though little information is available concerning the role of mDCs in RA, an increased percentage of mDCs [39] and upregulated levels of CD86 activation marker and CCR7 chemokine receptor [40], in the PB of RA patients have been reported; also, mDCs infiltrating the synovium express the proinflammatory cytokines IL-12p70, IL-15, IL-18, IL-23, and IFN-β [37].