Autografting for patients with chronic myeloid leukaemia in chronic phase: peripheral blood stem cells may have a finite capacity for maintaining haemopoiesis.

We treated 14 patients with Ph-chromosome-positive chronic myeloid leukaemia still in chronic phase by autografting with blood-derived haemopoietic stem cells. Eleven patients were autografted electively after cytoreductive treatment with busulphan (16 mg/kg) and melphalan (60 mg/m2) and three were autografted after marrow cells from HLA-identical sibling donors had failed to engraft. In 13 patients haemopoiesis recovered; one failed to engraft and died 114 d after autografting. Two other patients became pancytopenic and received further stem cell transfusions at 3 and 40 months respectively after first autografting. One patient entered lymphoid transformation and died 14 months after autografting. Twelve patients survive at a median of 41 months (range 24-53) after autografting. Nine of the survivors have required further chemotherapy after autografting and four of the nine were electively autografted on a second occasion. Three patients surviving after autografting for 28, 43 and 53 months respectively have not required further chemotherapy. In two of these patients haemopoiesis is now predominantly Ph-negative. We conclude that autografting in chronic phase might prolong survival in some cases by reducing the size of the leukaemic stem cell population. The fact that initially successful grafts failed in two patients suggests that blood-derived stem cells may have a finite potential for self-replication.