Homeostatic and pathogenic role of renal dendritic cells.

Dendritic cells (DCs) form a bridge between the innate and adaptive immune systems and fundamentally have an impact on anti-infectious defense and immune-mediated diseases, including those affecting the kidney. The field of renal dendritic cells (rDCs) is rapidly evolving, and work in rodent models has provided the first insight into their functional role in kidney homeostasis and disease. Recent findings indicate that rDCs have an important sentinel role against kidney injury and infection. In acute immune-mediated disease they function in an anti-inflammatory manner, but may acquire pro-inflammatory functionality when renal inflammation becomes chronic. In chronic disease rDCs mature and stimulate rather than tolerize effector T cells, and may contribute to progression of kidney disease. Recent progress in aligning murine and human DC subsets has opened avenues for making knowledge obtained from mechanistic studies in animal models available for better interpretation of kidney biopsies. There is firsthand evidence indicating changes in human DC subsets and their distribution in some kidney diseases. Data are presently lacking on the identity of rDC progenitors, the molecular mechanisms governing their recruitment into the kidney, and the role of rDCs in kidney homeostasis. This review highlights recent findings in the study of rDCs.