CD1A and rheumatoid arthritis: In this context, especially CD14+CD1a+CD1c+ inflammatory DCs (locally differentiating from monocytes invading the inflamed joint) in synovial fluid were suggested to play an important role in the pathogenesis of RA by effectively activating Th17 cells in RA joints via their production of TGF-β, IL-1β, IL-6, and IL-23 [31].