Donor lymphocyte infusion in myeloid disorders.

A number of modalities including both pharmaceutical and cell-based treatments have long been tested and developed to prevent and treat relapses after allogeneic stem cell transplantation (allo-HSCT). The ability of donor T cells to recognize antigenic structures on leukemic cell surfaces and destroy them is a well-known fact. Based on this fact, the idea of using donor T cells to contribute to the development of adoptive immunotherapy has emerged. Donor lymphocytes are easy to obtain and donor lymphocyte infusions (DLI) have a simple rational while this treatment modality is an effective example of cellular therapy. The group of chronic myeloid leukemia patients who are more likely to benefit from DLI include: a) patients in the chronic phase of hematologic relapse and b) patients with molecular/cytogenetic relapse. DLI appear to be an appropriate treatment option to be used in combination with conventional chemotherapy or hypomethylating agents in the treatment of post-allo-HSCT relapse for acute myeloid leukemia and myelodysplastic syndrome, if:) the burden of tumor is low b) the relapse is at a molecular level rather than an overt hematologic relapse c) the patient has favorable cytogenetic characteristics d) time interval between transplantation and relapse is relatively longer (>5 months) e) response could be obtained after salvage therapies. In the event that minimal residual disease (MRD) or increasing mixed chimerism is detected, prompt administration of DLI for prophylactic purposes without waiting for a manifest relapse, was found to be effective in inducing a full donor chimerism and overcoming MRD and eventually preventing a manifest relapse.