A potentially important role for T cells and regulatory T cells in Langerhans cell histiocytosis

Langerhans cell histiocytosis is characterized by lesions containing inflammatory immune cells, including myeloid cells and T cells. Patient mortality remains unacceptably high and new treatment options are required. Several LCH studies have identified aberrant frequencies of T cell subsets with potential immune regulatory properties. High numbers of Foxp3+ regulatory T cells and gamma-delta T cells have been reported in patients with LCH, although, the cause of their presence or their significance is not yet clear. This review describes the current understanding of how LCH develops and progresses, focusing on the growing evidence that regulatory T cell subsets may be important and discussing the exciting potential for harnessing these cells to treat LCH using immune based therapies.