PROLONGED REMISSION AND AUTOLOGOUS RECOVERY IN 2 PATIENTS WITH CHRONIC MYELOGENOUS LEUKEMIA AFTER GRAFT FAILURE OF ALLOGENEIC BONE-MARROW TRANSPLANTATION

Two patients with Philadelphia-positive chronic myelogenous leukemia u nderwent allogeneic bone marrow transplantation from a related HLA mis matched donor (patient 1) or from an unrelated HLA-identical donor (pa tient 2). Following bone marrow transplantation partial engraftment (p atient 1) or graft failure (patient 2) occurred followed by autologous Philadelphia negative hematopoietic recovery either spontaneously (pa tient 1) or after infusion of autologous bone marrow rescue (patient 2 ). Neither Philadelphia chromosome, nor bcr-abl rearrangement was dete ctable by PCR analysis up to 7 years (patient 1) and 9 years (patient 2) post-transplantation. These two observations indicate that sustaine d engraftment of allogeneic bone marrow stem cells following a myeloab lative regimen is not necessary to cure chronic myelogenous leukemia. It is hypothesized that the proliferative advantage of Philadelphia-ne gative progenitors and the anti-leukemic effect of lymphocytes in the graft have resulted in prolonged remission of the patients.