title: Autologous bone marrow transplantation in acute myelogenous leukemia: in vitro treatment with myeloid-specific monoclonal antibodies and drugs in combination.
abstract: We report the results of a preclinical study comparing four different purging protocols using a promyelocytic human cell line HL-60 and myeloid leukemic progenitor cells (colony-forming unit-leukemic [CFU-L]) from acute myelogenous leukemia (AML) patients assayed in semisolid culture. We studied the antileukemic effect of (1) Single-cycle complement-mediated lysis by two different monoclonal antibodies (MoAbs) (M195 [CD33] and F23 [CD13] 40 micrograms/mL), reactive with distinct antigens found on early myeloid cells and monocytes, used alone and in combinations; (2) 4-Hydroperoxycyclophosphamide (4-HC) (80 mumol/L or 100 mumol/L) alone; or (3) combined with VP-16 (5 micrograms/mL) and (4) a cocktail of 1 through 3 as above (combined immunochemotherapy). More than 4 logs of HL-60 tumor cell elimination were observed after 1 hour of incubation with both MoAbs plus 4-HC + VP-16 while the single treatment (immunotherapy or chemotherapy) provided 1.5 and 3.5 logs of colony-forming inhibition, respectively. When the same protocols were tested on cryopreserved leukemic cells from eight patients with AML, we observed a mean value of CFU-L inhibition of 92.3% +/- 2.5% SD, 95.5% +/- 1.4% SD, and 99% +/- 0.8% SD after MoAbs and complement lysis, 4-HC, and 4-HC + VP-16 treatment, respectively. The combined treatment of MoAbs and 4-HC + VP-16 produced more than 3-log reduction of CFU-L colony formation. By comparison, the mean recovery of committed normal bone marrow progenitors after incubation with MoAbs and complement was 12% for CFU-granulocyte-macrophage (CFU-GM), 22.9% for burst-forming unit erythroid (BFU-E), and the recovery following 4-HC + VP-16 treatment was 4.4% for CFU-GM and 5.6% BFU-E. In subsequent experiments, highly purified CD34+ blast cells, enriched by positive selection, and stimulated in liquid culture by cytokines (interleukin-1 [IL-1], IL-3, and combination of both) or MO-conditioned medium (MoCM), demonstrated that immunochemotherapy spares hematopoietic colony-forming cells earlier than day 14 CFU-GM, in vitro.
authors.affiliation: Laboratory of Hematopoietic Cell Kinetics, Memorial Sloan-Kettering Cancer Center, New York, NY 10021.
authors.forename: R M
authors.initials: RM
authors.lastname: Lemoli
authors.forename: C
authors.initials: C
authors.lastname: Gasparetto
authors.forename: D A
authors.initials: DA
authors.lastname: Scheinberg
authors.forename: M A
authors.initials: MA
authors.lastname: Moore
authors.forename: B D
authors.initials: BD
authors.lastname: Clarkson
authors.forename: S C
authors.initials: SC
authors.lastname: Gulati
mesh_terms: D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000627:therapeutic use*; D016026:Bone Marrow Transplantation / Q000276:immunology; D002460:Cell Line; D003114:Colony-Forming Units Assay; D003520:Cyclophosphamide / Q000031:analogs & derivatives / Q000627:therapeutic use; D003602:Cytotoxicity, Immunologic; D005047:Etoposide / Q000627:therapeutic use; D005260:Female; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000276:immunology; D006801:Humans; D007165:Immunosuppression Therapy; D007375:Interleukin-1 / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology; D015470:Leukemia, Myeloid, Acute / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D014182:Transplantation, Autologous
chemical_list: D000911:Antibodies, Monoclonal; D007375:Interleukin-1; D007377:Interleukin-3; C012358:4-hydroxycyclophosphamide; D005047:Etoposide; D003520:Cyclophosphamide