[Hairy cell leukaemia. I. Clinical features, cytochemistry, phagocytosis, establishment of permanent growing cell lines (author's transl)].

In seven patients the diagnosis of hair cell leukaemia (leukaemic reticuloendotheliosis) was confirmed cytochemically and histologically. Splenectomy, in six patients, apparently favourably influenced the course. Isoenzyme 5 of the acid phosphatase was demonstrated in the hairy cells of all patients. Reaction of alpha-naphthylacetate esterase was moderately positive in the hairy cells. Phagocytosis of latex and India-ink particles was demonstrated especially in tartrate-resistant cells of one patient. In two patients eight permanently growing cell lines were demonstrated from leucocytes and defined cytochemically. Capacity for phagocytosis of hairy cells and positive reaction of alpha-naphthylacetate esterase in the hairy cells suggest properties of monocytes. But it is not possible definitively to classify the hairy cells among B-cells or monocytes.