[Differentiation therapy for myelodysplastic syndrome]

The ability of induction of differentiation of leukemia cells was first proved by cultured leukemia cells, and such ability has been also confirmed clinically as a result of observation of the dramatic effect of all-trans retinoic acid on acute promyelocytic leukemia and the usefulness of low-dose of ara-C therapy for acute myeloid leukemia. We studied differentiation induction of primary cultured bone marrow cells from myelodysplastic syndrome (MDS) patients by ara-C and VP16 with or without addition of G-CSF. We also studied clinical efficacy of differentiation therapy in 56 patients with MDS. Differentiation induction effects were observed in 3 of 14 patients treated with G-CSF in combination with low-dose of ara-C or low-dose of VP16. In addition, high-dose methylprednisolone therapy, GM-CSF and anabolic steroid therapy also showed similar effect on refractory anemia, even in a few patients. Since these results suggested the usefulness of differentiation therapy of MDS, it is earnestly hoped that more effective therapy, including a concomitant use of cytokine, might be established as soon as possible.