Purpose: To compare results of syngeneic, allogeneic, and autologous hematopoietic stem-cell transplantation for non-Hodgkin's lymphoma (NHL).
Patients and methods: The databases of the International Bone Marrow Transplant Registry (IBMTR) and the European Group for Blood and Marrow Transplantation were used to identify 89 NHL patients who received syngeneic transplants. These patients were compared with NHL patients identified from the IBMTR and the Autologous Blood and Marrow Transplant Registry who received allogeneic (T-cell depleted and T-cell replete) and autologous (purged and unpurged) transplants.
Results: No significant differences in relapse rates were observed when results of allogeneic transplantation were compared with syngeneic transplantation for any histology. T-cell depletion of allografts was not associated with a higher relapse risk, but was associated with improved overall survival for patients with low-grade and intermediate-grade histology. Patients who received unpurged autografts for low-grade NHL had a five-fold (P =.008) greater risk of relapse than recipients of syngeneic transplants, and recipients of unpurged autografts had a two-fold (P =.0009) greater relapse risk than patients who received purged autografts. Among low-grade NHL patients, the use of purging was associated with significantly better disease-free survival (P =.003) and overall survival (P =.04) when compared with patients who received unpurged autografts.
Conclusion: These analyses failed to find evidence of a graft-versus-lymphoma effect, but do provide indirect evidence to support the hypothesis that tumor contamination may contribute to lymphoma relapse, and that purging may be beneficial for patients undergoing autologous hematopoietic stem-cell transplantation for low-grade NHL.