The pathogenic role of type I interferons (IFNs) in the development of different autoimmune diseases has been extensively described in the literature. Since plasmacytoid dendritic cells (pDCs) are the main source of type I IFNs, there is evidence of the involvement of pDCs in autoimmune diseases. The CD303 surface protein (also called BDCA-2) is specifically expressed by the pDCs.