抄録
The five patients with megakaryoblastic leukemia were treated with recombinant human gamma interferon (γIFN). γIFN of six million to twelve million U/day was given by drip infusion for 21 to 150 days. As a result, the absolute number of blasts in the peripheral blood, and/or bone marrow decreased, and neutrophils and monocytes increased in two patients who had transformed from refractory anemia with excess of blasts (RAEB). The number of blasts decreased transiently in a patient who had developed as acute myelofibrosis, but the blast increased rapidly while γIFN was given. In other two patients, the blasts also increased during the treatment with γIFN.
The influence of γIFN on leukemic megakaryoblastic colony formation was studied in vitro in these patients before therapy. The colony assay with methylcellulose method revealed that γIFN suppressed the proliferation of progenitors dose-dependently in the two patients who responded to the treatment with γIFN. The number of colonies increased according to the increase in γIFN in two patients out of three who did not respond to the treatment with γIFN. Furthermore, the receptor assay was performed using 125I-labelled γIFN. The number of receptors on the cell surface was around 8,000/cell in two patients who responded, although the number was below 1,400/cell in patients who did not. Kd was around 4×10-10M in all patients without difference.
Thus it is suggested that γIFN is effective in a part of patients with megakaryoblastic leukemia. The response of theray may be predicted by both colony assay and receptor assay.
