Disappearance of Ph1-positive cells in four patients with chronic granulocytic leukemia after chemotherapy, irradiation and marrow transplantation from an identical twin

Abstract

Four patients (21, 41, 13 and 38 years of age) with a history of chronic granulocytic leukemia for 12, 10, 11, and 106 months, respectively, were treated with dimethyl busulfan, cyclophosphamide, 920 rads of total-body irradiation and intravenous marrow infusion from normal, genetically identical twins. Serial chromosome analyses were performed on marrow aspirates cultured without mitotic stimulants. No Ph1-positive cells were detected in the marrows from the normal twins, whereas just before therapy, all 100 metaphases examined from each patient were Ph1-positive. Chromosome analyses were performed three to five times per patient after transplantation, and not a single Ph1-positive cell was detected. The patients remain hematologically normal 22, 23, 26 and 31 months after transplantation. The results show that the Ph1-positive clone can be eradicated by vigorous therapy and that the marrow in chronic granulocytic leukemia can be repopulated by stem cells from normal twins.