Impact of donor lymphocyte infusion for hematological malignancy relapsed after allogeneic bone marrow transplantation

We studied the ability of donor lymphocytes collected by leukapheresis to induce graft-versus-leukemia-reactions in fifteen patients (6 CML, 4 AML, 2 ALL, and 3 high grade NHL) that had relapsed after allogeneic bone marrow transplantation. Eight donors were mobilized with G-CSF before collecting lymphocytes by apheresis. The patients were monitored for toxic effects and hematological and cytogenetic responses. Eight patients (53%) responded to the donor lymphocyte infusions (DLI). Four of six patients with relapsed CML had molecular remissions with no detectable cells containing bcr/abl messenger RNA transcripts. One of four AML patients and three of five patients with ALL/NHL showed complete hematological and/or cytogenetic remissions after DLI. Response rates were greater in patients who received more than 1 x 10⁸ CD 3+ cells/kg and in patients who relapsed more than 6 months after BMT (p = NS). Response to DLI was significantly associated with the development of acute or chronic graft versus host disease. Seven of nine patients with clinical evidence of GvHD following donor lymphocyte infusion had a hematological and/or cytogenetic response to DLI compared to one of six patients who achieved a CR following DLI without evidence of GVHD (p = .05). Four patients who achieved complete remissions following DLI remain alive in CR eight to 29 months (median 18 months) after DLI (2 CML, 2 ALL/immunoblastic NHL). We conclude that DLI can be effective for ALL and NHL as well as CML, and that G-CSF stimulation of donors did not produce a significant change in the frequencies of either remission and/or GVHD post DLI.