Purging of peripheral blood progenitor cell autografts and treatment of minimal residual disease

Clinical success of autologous peripheral blood progenitor cell (PBPC) transplantation is challenged by relapse of malignant disease which might at least in part be mediated by graft-contaminating tumor cells, Although the clinical efficacy of tumor cell depletion still remains to be demonstrated, multiple purging strategies are currently pursued in the context of autologous stem cell transplantation. This report discusses ex vivo manipulations of PBPC transplants with respect to purging of tumor cells, including positive selection of CD34(+) cells with or without negative depletion of tumor cells as well as ex vivo expansion techniques. Moreover, strategies with an adoptive immunotherapy using ex vivo-generated autologous dendritic cells for the treatment of minimal residual disease after stem cell transplantation will be discussed here.