Immunohistochemical double staining for myeloid dendritic cell markers. (A): Immunohistochemical double staining for DC-SIGN+ interstitial type dendritic cells (red) and langerin+ Langerhans type dendritic cells (Blue) in small airway of human lung. Langerin+ cells are mainly present in the epithelium, whereas DC-SIGN+ cells are localized in the lamina propria and adventitia. There are no double positive cells, confirming the segregation of these two cell types in human lung. (B): Immunohistochemical double staining for BDCA-1+ myeloid dendritic cells and langerin+ Langerhans type dendritic cells in small airway of human lung. A single positive BDCA-1 + cell (red), a langerin positive cell (blue) and a double positive cell (purple, marked with an arrow) are present.