POTENTIAL OF AUTOLOGOUS IMMUNOLOGICAL EFFECTOR-CELLS FOR BONE-MARROW PURGING IN PATIENTS WITH CHRONIC MYELOID-LEUKEMIA

Relapse is a major concern in autologous bone marrow transplantation ( BMT), Therefore, purging of bone marrow to reduce the amount of tumor cells reinfused into the patient is widely used. Immunologic effector cells such as lymphokine activated killer (LAK) cells are attractive f or purging of bone marrow since these cells might have an additional i n vivo effect on tumor cells in contrast to other purging protocols. I n patients with chronic myelogenous leukemia (CML), LAK cells can only be used in some patients for purging bone marrow since LAK cells poss ess no or only limited cytolytic activity against autologous CML tumor cells in most cases. In this study, we investigated the effect of aut ologous and allogeneic cytokine-induced killer (CIK) cells on tumor ce lls from patients with CML. CIK cells have been generated from periphe ral blood lymphocytes by incubation with interferon-gamma on day 0, in terleukin-1, interleukin-2 and a monoclonal antibody against CD3 on da y 1. In contrast to LAK cells, CIK cells were able to lyse both autolo gons and allogeneic cells from patients with CML as determined by a Cr -51 release and a tumor colony assay, The cytotoxicity of CIK cells ag ainst CML cells was confined to the CD56(+) population. CIK cells show ed no major toxic effect on hematopoietic progenitor cells when tested in CFU-GM assays. CIK cells eliminated three orders of magnitude of K 562 cells and less than one order of magnitude of progenitor cells (25 % reduction). This represents a differential effect of CIK cells on tu mor and progenitor cells. These studies show that CIK cells may be mor e useful than LAK cells for purging of autologous bane marrow in the c ontext of autologous BMT,