Cutting edge: migration of langerhans dendritic cells is impaired in autoimmune dermatitis.

Tissue-resident dendritic cells, such as Langerhans cells (LC), normally carry Ags from tissues to lymph nodes to induce immunity to tissue Ags. In this study, we report that LC are reduced in the skin-draining lymph nodes of MRL-Fas(lpr/lpr) and MRL-Fas(+/+) mice that develop T cell-mediated autoimmune skin inflammation as compared with MHC-matched healthy strains. This deficiency of LC in skin-draining lymph nodes is due to a profound impairment of LC migration, resulting in the accumulation of activated LC in the skin. Such a defect in LC migration develops before the onset of skin lesions and correlates with the onset and severity of dermatitis. The reduced, rather than increased, migration of LC from skin to skin-draining lymph nodes represents a novel functional abnormality of LC in autoimmune dermatitis.