[In vitro studies of cells in histiocytosis X]

In a female patient with histiologically ensured histiocytosis X, cell cultures modified according to NEZELOF were performed in methylcellulosis and Eagle's medium. From the 5th to the 15th day of incubation the cells were daily observed natively through a normal microscope and taken for histochemical examinations and for checking their capacity of phagocytosis. Two cell types could be distinguished: spindle-shaped fibroblasts as well as round cells of changing form and size, the alpha-naphthylacetate esterase response of which proved to be positive. The round cells can partly be regarded as HK cells, whereas giant cells could be predominantly observed during the second week. A phagocytosis of iron chips and human erythrocytes loaded with antibodies could be revealed in both types. HK cells represented mature macrophages, from which giant cells developed under in vitro conditions. There is still not explanation as to the local and immunological factors characterizing the clinical picture of histiocytosis X.