Monocyte-derived IL-10-secreting dendritic cells in choroid plexus epithelium.

Choroid plexuses form an interface between peripheral blood and cerebrospinal fluid. Dendritic-like cells have been reported in a few studies of choroid plexuses in man. Here we used electron microscopy and immunophenotyping to precise the morphologic features and phenotype of these cells. Examination of 10 human choroid plexuses evidenced intra-epithelial dendritic cells with a clear cytoplasm, reniform nucleus and long expansions. These cells express MHC Class II, CD11b, CD14, CD32, CD68 and IL-10, but not CD40, CD80 or CD86, suggesting an immunosuppressive role for these dendritic cells. Their sentinel position could make them participate to the immunological silence of the brain.