The graft-versus-myeloma effect

Although high-dose therapy and autologous transplantation confer a survival benefit in multiple myeloma [1,2], eventual disease progression is almost universal and few patients are cured [1-3]. Disease recurrence rates after purged autografts do not appear to be different from those seen with unpurged grafts [4], and relapse rates after syngeneic transplantation are also high [5,6]. This situation is unlike that in hematological malignancies such as the acute leukemias and the lymphomas, where a number of patients are cured with autologous or syngeneic transplantation [7], suggesting that currently available conditioning regimens alone are incapable of eradicating myeloma. Although relapse rates are high after allogeneic bone marrow transplantation (BMT) in myeloma [8-10], some patients do attain sustained molecular remissions [11] and become long-term disease-free survivors [8-10,12,13]. This suggests that an immunological graft-versus-tumor effect similar to the well-characterized graft-versus-leukemia [GVL] reactions [14] operates in the setting of allogeneic transplantation for myeloma.