[Long-term cultures in polycythaemia vera as proof for dependence on erythropoietin (author's transl)].

In eight patients suffering from polycythaemia vera, the proliferation of erythroid colonies in methylcellulose with and without exogenous erythropoietin was studied. After three and five weeks, respectively, no colonies grew. Due to addition of erythropoietin more erythroid colonies proliferated which could be cultivated over nine weeks. The experiments suggest that the erythropoiesis in polycythaemia vera depends on erythropoietin.