[Donor leukocyte transfusion in a patient with relapsed chronic myeloid leukemia after allogeneic bone marrow transplantation: analysis of natural killer cell activity and T-cell receptor repertoire in bone marrow T cells that exhibited graft-versus-leukemia activity].

Hematologic relapse of chronic myeloid leukemia developed in 37-year-old man 255 days after allogeneic bone marrow transplantation. The patient received a donor lymphocyte transfusion (DLT) twice at a dose of 5 x 10(6)/kg T cells. He achieved complete cytogenetic response (CCR) 14 weeks after DLT, and has remained in a CCR state for 17 months. Neither acute nor chronic graft-versus-host disease (GVHD) was observed. Natural killer (NK) cell activity was elevated. Also, analysis of the T cell receptor (TCR) repertoire disclosed oligoclonal expansion of T cells of the TCR V beta and J beta subfamilies. These observations provide evidence for the clonal expansion of allogeneic T cells that are capable of mediating antileukemic activity without causing GVHD.