Plasmacytoid dendritic cells: in search of their niche in immune responses.

Plasmacytoid dendritic cells (pDCs) have been associated with several names and functions over time, reflecting the limited availability of specific markers and their ability to produce large amounts of type I interferons, present antigens, as well as prime disparate T-cell helper responses. Yet, there is increasing evidence that pDCs are a distinct cell type in the innate immune system. This review highlights aspects in which pDCs are unique in comparison to other antigen-presenting cells in regulating innate and adaptive immune responses.