[Ex-vivo treatment of a bone marrow graft]

The use of bone marrow transplantation is increasing in the management of advanced cancers. In autologous bone marrow transplantation (ABMT), many investigators have attempted to purge the graft of residual tumor cells because of concern that reinfused tumor cells might contribute to relapse. The feasibility of various methods (exposure to chemical agents, monoclonal antibodies (MoAbs), toxins, dye, magnetic microparticles ... ) has been confirmed. In allogeneic bone marrow transplantation, clinical studies have related the prevention of graft-versus-host disease reaction through the partial depletion of T lymphocytes in the donor graft limited to 1 log to maintain a graft-versus-leukemia (GVL) effect. Similarly, the feasibility of different assays (soybean agglutinin, Moabs and magnetic microparticles) have been shown. However, the clinical benefit of BM purging remains to be demonstrated. For ABMT, only recent data on B-cell lymphoma and leukemia strongly support the clinical usefulness of an ex-vivo purging. For allogeneic BMT, one question remains controversial: is T lymphocytes depletion the best method for GVHD prevention?