Non-leukemic autologous reconstitution after allogeneic bone marrow transplantation for Ph-positive chronic myelogenous leukemia: Extended remission preceding eventual relapse

Autologous reconstitution is the recovery of autologous hematopoietic function after failure of an allogeneic graft to establish sustained hematopoiesis either with or without preceding donor engraftment. We reviewed 9 years experience of the University of Minnesota and identified 10 of 291 patients who underwent allogeneic BMT for Ph-positive CML and developed non-leukemic autologous reconstitution. All patients received the same preparative regimen with cyclophosphamide and total body irradiation. Eight patients had a 6/6-antigen matched donor. Eight patients received their graft from an unrelated donor. In five cases the graft was T cell-depleted. Non-malignant autologous reconstitution initially manifested as mixed chimerism in nine of 10 patients and lasted for a median of 11 (3-41) months. Eight patients have relapsed and four are still alive. The two relapse-free patients have died 24 and 48 months post transplant. Of the four surviving patients, two are in interferon-induced cytogenetic remission at 53+ and 101+ months of follow-up. Autologous non-leukemic reconstitution is uncommon, but appears to be a distinct clinical syndrome, perhaps occuring more frequently after unrelated donor BMT. Although usually followed by relapse, relapse-free survival may be prolonged.