[Thrombocytosis in chronic myelogenous leukemia (CML) controlled by interferon alpha (IFN-alpha)]

A 39-year-old Japanese female who had been followed as chronic myelogenous leukemia (CML) since 1984 was admitted to our hospital because of dizziness. On admission, platelet count markedly increased (245 X 10(4)/microliters) in spite of daily administration of busulfan 2 mg. She was diagnosed as accelerated phase CML with thrombocytosis. So we tried to use interferon alpha (IFN-alpha) finally given in a dose of 9 X 10(6) U daily by subcutaneous injection. After that, platelet count decreased to 70 X 10(4)/microliters and megakaryocyte count in bone marrow decreased from 887.5/microliters to 395.7/microliters. But we had to stop IFN-alpha because of severe side effects.