Figure 2.

IL-10 prevents maturation of Langerhans cell histiocytosis (LCH) cells. LCH cells express CD40 at higher levels than normal Langerhans cells. When cocultured with CD40L-transfected fibroblasts, they become mature cells and express high levels of membrane MHC class II molecules that link antigens presented by T cells through both T-cell receptor and CD86, the costimulatory molecule binding CD28 for full activation. IL-10 produced by intralesional macrophages downregulates the expression of both molecules on the surface of LCH cells.

Abbreviations: IL10, interleukin 10; iLCH, immature Langerhans cell histiocytosis; MØ, macrophage; MHCII, major histocompatibility complex II; mLCH, mature Langerhans cell histiocytosis; T-reg, regulatory T cells; TCR, T-cell receptor; TH, T helper.