Use of Recombinant Human Interleukin-2 in Conjunction With Syngeneic Bone Marrow Transplantation in Mice as a Model for Control of Minimal Residual Disease in Malignant Hematologic Disorders

Unlike allogeneic bone marrow transplantation (BMT), autologous BMT is not accompanied by immune-mediated graftversus-leukemia (GVL) effects; hence, the relapse rate observed after autologous BMT in malignant hematologic disorders is higher than that observed after allogeneic BMT. Autologous BMT represents a much safer medical procedure available for many patients in need in situations where allogeneic BMT is not feasible or risky. The present experiments were designed to investigate whether it might be possible t o combine the therapeutic benefits of autologous BMT with additional immunotherapy after BMT. The tumor model used for investigating GVL effects was the murine B-cell leukemia (BCLl), a spontaneous, nonimmunogenic, highly lethal leukemia of BALB/c origin. BALB/c mice inoculated with lo3 BCLl leukemia cells were treated on day -1 with cyclophosphamide 100 mg/kg and transplanted with normal syngeneic BM cells on day 0. High-dose recombinant interleukin-2 (rlL-2) (100,000 Cetus units x 3/day intraperitoneally x 5 consecutive days) was initiated on day +1, +7, or