Reactivity of histiocytosis X cells with monoclonal antibodies.

Histiocytosis X cells were demonstrated to react with T6 antigen as well as with the M1 and I1 markers of monocytes using immuno-electron microscopy and double labeling immunofluorescence technique. The data confirm the close relationship existing between histiocytic X cells, Langerhans cells and dendritic cells, and suggest to consider the T6 antigen either as an early differentiation marker of thymocytes or as a functional marker of Mononuclear Phagocyte System subpopulations.