Vim-2, candidate monoclonal antibody for purging autologous marrow grafts in acute myeloblastic leukaemia

In this report we present a method for purging acute myeloid leukaemia progenitors (AML-CFU) from autologous marrow grafts. Previous studies using flow cytometry and cell sorting had indicated that the monoclonal antibody (MCA) Vim-2 reacts strongly with AML-CFU in a significant number of cases, whereas the majority of normal bone marrow precursors are Vim-2 negative. To investigate the applicability of Vim-2 for selective purging, we performed complement-dependent cytotoxicity experiments and determined the specific lysis of AML-CFU. In 11 of 17 patients, 97.5 +/- 4% (mean +/- SD) of AML-CFU were killed following immune-mediated lysis. Multi-lineage normal haematopoietic progenitors (CFU-GEMM) were not significantly affected by the MCA Vim-2-mediated complement lysis. These data suggest that the MCA Vim-2 is a useful reagent for the elimination of residual AML progenitor cells from remission bone marrow in patients subjected to autologous marrow transplantation.