Autologous stem-cell transplantation is widely accepted as effective therapy for patients with relapsed aggressive B-cell non-Hodgkin lymphomas. Although 40-60% of younger patients with diffuse large cell lymphoma can expect to be cured, substantial numbers will experience a relapse. In addition, certain histologic subtypes are associated with particularly poor prognoses with combination chemotherapy alone (e.g., mantle cell lymphoma). Relatively few of these patients will experience long-term responses. Although other NHL subtypes are associated with more favorable prognoses in terms of overall survival, they are rarely cured (e.g., follicular lymphoma, chronic lymphocytic leukemia). Allogeneic transplantation has been increasingly utilized in patients with lymphoid malignancies but is associated with high toxicity. Recently, reduced-intensity conditioning regimens have shown encouraging results, attributed to graftversus-lymphoma effects. This article discusses changes in the way autologous and allogeneic transplants may be carried out in the future to treat patients with lymphoid malignancies.Recurrent non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL) have a poor prognoses with conventional chemotherapy.1,2 Intensive research with novel chemotherapy regimens has been conducted, but patients with recurrent disease typically have only a transient response to salvage therapies and ultimately die of their disease. Autologous and allogeneic blood and marrow transplantations have decreased morbidity and mortality rates as a result of improvements in stem cell transplantation (SCT) procedures and supportive care. As a result, there has been an increase in the use of SCT in lymphoid malignancies.
Improvements in SCT for NHL and CLLToxicity related to intense preparative regimens, graft-versus-host-disease (GVHD), and infections remain the main cause of failure after high-dose chemoradiotherapy and allogeneic SCT. The treatment-related mortality (TRM) rate of this approach has been substantial, with a 30-40% risk of death within 100 days of the transplantation. The use of recently introduced reduced-intensity and truly nonmyeloablative conditioning regimens has shifted some or all of the burden of tumor-cell kill from the conditioning regimens to the graft-versus-tumor effects. These regimens are less toxic than conventional regimens and allow for the treatment of older patients and patients with comorbid conditions.The inclusion of targeted therapies that are focused on the recipient's abnormal cells and hematopoietic system while sparing all other organs; better donor selection, with improvements in histocompatibility typing procedures; new prophylactic antifungal agents; and early detection of cytomegalovirus reactivation by sensitive methods have all contributed to the decreased TRM risk of allogeneic SCT.Unlike allogeneic SCT, autologous SCT has been associated with a TRM of < 5% but has also been associated with a higher risk of relapse related to contamination of the graft and persistence of min...