In vitro cytokine-primed leukaemia cells induce in vivo T cell responsiveness in chronic myeloid leukaemia

We previously showed that in chronic myeloid leukaemia (CML), it is possibl e to induce costimulatory molecules, CD80/CD86, on leukaemia cells by cultu ring adherent peripheral blood mononuclear cells from these patients with I L-4 and GM-CSF, In addition to the expression of CD80/CD86 molecules, some of the leukaemia cells also expressed the dendritic cell marker, CD1a, When these leukaemia cells were used in mixed lymphocyte leukaemia reactions, t hey mediated antologous T cell proliferation not seen when fresh leukaemia cells were used as the stimulator cells. In this study, we showed that rein fusion of these immunogenic leukaemia cells to the autologous hosts resulte d in priming in vivo of T cells so that they could respond to subsequent re challenge in vitro with fresh autologous leukaemia cells. Although cytotoxi c T cells against leukaemia cells were not demonstrated, these T cells coul d proliferate and produce interferon-gamma when cocultured in vitro with th e leukaemia cells, Our findings therefore provide further evidence for the immunogenicity of these cultured leukaemia cells in CML.