Dendritic cells: friend or foe in autoimmunity?

This article summarizes recent advances in dendritic cell (DC) biology as related to normal and abnormal physiology. The large amount of information acquired from human and animal models substantiates that the DC lineage system represents a double-edged sword in the immune system and a critical link between innate and acquired immunity Presumably, in normal physiology, tolerizing DCs guard against autoimmunity and control established immune reactions, whereas immunogenic DCs provide active host defenses. In autoinmume diseases, there is strong evidence to support the idea that tolerance is overridden by the development of immunogenic DCs that favor cross-priming and stimulation of autoreactive lymphocyte responses.