Induction of graft versus malignancy effect after unrelated allogeneic PBSCT using donor lymphocyte infusions derived from frozen aliquots of the original graft.

To evaluate safety and efficacy of donor lymphocyte infusions (DLI), derived from frozen aliquots of the original G-CSF-stimulated graft after allogeneic PBSCT from unrelated donors, data of 121 patients with hematological malignancies treated with DLIs were retrospectively analyzed. Indications for PBSCT were AML/myelodysplastic syndrome (n=63/8), ALL (n=17), lymphoma (n=13), multiple myeloma (n=10) and myeloproliferative syndrome (n=10). Reasons for DLI were hematological relapse (n=81), molecular and/or cytogenetic relapse (n=5), mixed chimerism (n=22) and prophylactic DLI in high-risk patients (n=13). DLIs were well tolerated with no acute adverse reactions. DLI-induced acute-type GvHD (aGvHD) was observed in 19 patients and chronic-type GvHD (cGvHD) developed in 14 patients. Three patients died of GvHD complications. DLI induced CR, complete chimerism or PR in 34 patients; 24 patients had stable disease, 50 patients progressed and 13 patients were not evaluable for response. Objective response was more obvious for molecular relapse (5/5) or mixed chimerism (14/22) compared with hematological relapse (13/81). Median survival after first DLI was 10.4 months (95% confidence interval: 4.4-26.0). Cryopreserved G-CSF-stimulated DLI, derived from allogeneic grafts are safe and immunoreactive, and can be applied early in case of mixed chimerism and molecular or cytogenetic relapse.