Abstract SCI-7

The current paradigm suggests that Langerhans cell histiocytosis (LCH) results from an accumulation of epidermal dendritic cells also called Langerhans cells. This concept is based on phenotypic and ultrastructural observations showing that LCH lesions are infiltrated by CD1a+langerin+ cells, two features thought to be restricted to epidermal Langerhans cells. It has been difficult, however, to understand how Langerhans cells, which are normally restricted to stratified epithelia, could give rise to such a multifocal disorder. LCH research has been handicapped by the inability to develop reliable animal models and by the fact that for a long time very few markers were available to determine the origin and stage of differentiation of histiocytes, now renamed macrophage/dendritic cell lineages. This presentation will discuss recent progress in our understanding of the regulation of the Langerhans cell, macrophage, and dendritic cell lineages and discuss the relationship of these lineages with the LCH cell.

Disclosures:

No relevant conflicts of interest to declare.

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