Allogeneic stem cell transplantation for the non-Hodgkin's lymphomas and Hodgkin's disease

Certain poor-prognosis patients with non-Hodgkin's lymphoma and Hodgkin's disease, usually with recurrent and/or refractory disease, are rarely curable with standard chemoradiotherapy. Autologous hematopoietic stem cell transplantation has been shown to result in improved long-term disease-free survival in some of these patients. Unfortunately, a number of patients are not suitable for autologous transplantation due to a damaged stem cell pool involvement or other disease processes of the marrow. These patients may benefit from allogeneic stem cell transplantation. In addition to the therapeutic effect of high-dose chemotherapy with or without total body irradiation, an immunologic [i.e. graft-versus-lymphoma (GVLym)] effect may be present in some patients undergoing allogeneic transplantation, resulting in a lower relapse rate than autotransplants. However, allografts are almost always associated with a higher non-relapse mortality due primarily to graft-versus-host disease (GVHD); unfortunately, GVHD and GVLym are difficult to separate. Thus, full exploitation of this GVLym effect may require the modification of commonly used conditioning regimens; if successful, these modifications may allow an additional decrement in the incidence of relapse without additional morbidity. Also, when combined with lesser intensity conditioning, such may permit patients who otherwise would not be candidates for standard transplant regimens to be allografted.