Abstract
A 35-year-old man with Ph1-positive chronic myeloid leukemia in acute phase responded to vincristine and prednisolone therapy. The blasts were lymphoid in appearance and had a high level of terminal deoxynucleotidyl transferase activity, 27.8U/109 cells. Surface marker analysis showed that these blasts did not have surface immunoglobulins and receptors for sheep erythrocytes and Fc portion of either IgG or IgM. Vincristine and prednisolone therapy resulted in a normal leukocyte number and disappearance of the blasts in the peripheral blood, which might indicate return to chronic phase of CML, but the lymphoid cells remained about 70% in the bone marrow. Twenty weeks after the diagnosis of blastic transformation, typical myelobasts, but not lymphoid cells, increased markedly in the peripheral blood, and the patient died from infection and cerebral bleeding. The significance of TdT activity in the treatment of CML blast crisis was discussed.
