Recent progress in the biology of airway dendritic cells and implications for understanding the regulation of asthmatic inflammation.

Dendritic cells (DCs) are crucial in determining the outcome of antigen encounter and integrating signals derived from the antigen, its inflammatory context, and the host environment into a signal that can be read by naive T cells in the lymphoid tissues and by effector T cells in peripheral tissues. Airway DC subsets, however, induce different types of immune responses, with plasmacytoid DCs promoting tolerance and myeloid DCs inducing immunity. We also propose that airway DCs are not only crucial for sensitization to inhaled antigens, leading to allergy, but also play a crucial role in established inflammation and therefore represent a therapeutic target to prevent the development of airway diseases.