Nonmyeloablative transplantation for lymphoma.

Nonmyeloablative stem cell transplantation, also referred to as minitransplantation or reduced-intensity transplantation, is a novel approach to lymphoma treatment offering the lure of harnessing graft-versus-lymphoma (GVL) effects while decreasing regimen-related toxicity. The general concept is to provide a sufficiently immunosuppressive and moderately myelosuppressive treatment regimen to allow donor and host hematopoietic coexistence or chimerism. The most popular regimens incorporate a purine analog (eg, fludarabine) and an alkylating agent (eg, cyclophosphamide or melphalan). Newer regimens include the monoclonal antibody alemtuzumab, which may reduce the incidence of acute graft-versus-host disease (GVHD). Early reports demonstrate a GVL effect; however, the underlying lymphoma subtype and pace of disease often dictate which patients can capitalize on GVL benefits. Clinical reports show mixed results, which may reflect variations in patient selection. Although most patients successfully engraft, the effect on lymphoma control and GVHD must be evaluated carefully. Future investigations continue to delineate the optimal timing of nonmyeloablative transplantation, the optimal patient population, the optimal preparative regimen, and the optimal GVHD prophylaxis. Supportive care remains a critical component of management because the reduced-intensity regimens do not abrogate the risk of serious infection and many do not appear to decrease the incidence of chronic GVHD. Nonmyeloablative hematopoietic stem cell transplantation may broaden the applicability of allogeneic transplantation in malignant lymphomas, especially for indolent subtypes.