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 funct ion after failure of an allogeneic graft to establish sustained hematopoies is 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-leukemi c autologous reconstitution. All patients received the same preparative reg imen with cyclophosphamide and total body irradiation. Eight patients had a 6/6-antigen matched donor. Eight patients received their graft from an unr elated donor. In five cases the graft was T cell-depleted. Non-malignant au tologous reconstitution initially manifested as mixed chimerism in nine of 10 patients and lasted for a median of 11 (3-41) months. Eight patients hav e relapsed and four are still alive, The two relapse-free patients have die d 24 and 48 months post transplant. Of the four surviving patients, two are in interferon-induced cytogenetic remission at 53+ and 101+ months of foll ow-up. Autologous non-leukemic reconstitution is uncommon, but appears to b e a distinct clinical syndrome, perhaps occurring more frequently after unr elated donor BMT. Although usually followed by relapse, relapse-free surviv al may be prolonged.