Characterization of human megakaryocyte colony-stimulating factor in the urinary extracts from patients with aplastic anemia and idiopathic thrombocytopenic purpura

Using procedures that were effective in the purification of human urinary erythropoietin (Epo), we attempted initial purification of megakaryocyte colony-stimulating factors (CSF) in urinary extracts from patients with aplastic anemia (AA) and idiopathic thrombocytopenic purpura (ITP). Comparison of colony stimulation by purified human Epo and crude urinary extracts revealed: (1) that the pure Epo augments megakaryocyte colony formation in culture and (2) MEG-CSF activity is also present in materials other than Epo in the crude urinary extracts from the two types of patients. Similar to purification of Epo, ethanol precipitation and sulfopropyl-Sephadex chromatography provided twofold and threefold increases in the specific activity of MEG-CSF, respectively. In contrast to Epo, however, significant inactivation of MEG-CSF activity was seen with phenol treatment. The elution profile of MEG-CSF seen on hydroxylapatite chromatography of urinary extracts was different from that of Epo. These data provided a basis for initial steps for purification of MEG-CSF and support the notion that MEG-CSF is distinct from Epo.