Role of donor lymphocyte infusions in relapsed hematological malignancies after stem cell transplantation revisited.

BACKGROUND: Treatment of relapsed hematological malignancies after an allogeneic peripheral blood stem cell transplant (SCT) is challenging. Donor lymphocyte infusion (DLI) from the stem cell donor is an attractive clinical option to salvage this group of patients.

METHODS: We reviewed the important studies looking at donor lymphocyte infusion as a therapy for the treatment of hematological disorders that are either refractory to or have relapsed after allogeneic SCT.

RESULTS: The response to DLI is dependent upon type of disease, dose of infused lymphocytes, and the development of graft vs. host disease (GvHD). The best response rates are seen in patients with chronic myeloid leukemia (CML) followed by patients with lymphomas, multiple myeloma and acute leukemias, respectively. The responses in patients with CML are durable whereas durable responses in other diseases are rare.

CONCLUSIONS: Given the development of new drugs to treat some hematological diseases, DLI has taken a backseat. New modalities to target the infused cells to the tumor and new approaches to reduce GvHD that will augment the graft vs. leukemia/lymphoma (GvL) effect and decrease the injury to normal host tissues need to be developed. Understanding the factors and mechanisms that differentiate the GvL effect from GvHD will help in the development of newer treatment modalities.