CD19 and dermatomyositis: Both myeloid DCs and plasmacytoid DCs have been found in the muscle tissues of DM/PM/IBM patients, with a predominance of plasmacytoid DCs in DM and myeloid DCs in PM/IBM (plasmacytoid DCs were defined as BDCA-2+ or CD4+CD83+CD123+ and myeloid DCs as BDCA-1+ after excluding CD19+ B cells) [119-121].