A 57-year-old man, diagnosed as
Polycythemia vera (PV), had been treated with administrations of
Busulfan since 1984. Three years later, the number of neutrophils in peripheral blood increased to 50,000/microliters with progression of
splenomegaly, and the case was diagnosed as
Chronic neutrophilic leukemia (CNL) based on the criteria by Miura et al, in November, 1989. In spite of 6MP and
Busulfan therapy, marked neutrophilia and
splenomegaly progressed, and the patient died due to
liver dysfunction in June of 1991. To clarify the pathophysiology of PV and CNL, we studied the in vitro growth kinetics of hematopoietic progenitor cells in bone marrow of this unique case and made a comparison with those of 4 cases of PV and 4 normal volunteers employing
methylcellulose culture. As in other cases of PV, erythroid colonies were formed in culture of bone marrow from this patient without addition of
erythropoietin. Furthermore, spontaneous colonies derived from CFU-GM and CFU-Mix increased remarkably in this case only. The results suggest that the hematopoietic abnormalities in this case involve the multipotent stem cells as well as erythroid and granuloid-macrophage progenitors.