Role of allogeneic stem cell transplantation in relapsed or refractory Hodgkin's disease

Little information is available regarding allogeneic stem cell transplantation (alloSCT) and Hodgkin's disease (HD). Autologous stem cell transplantation (autoSCT) is usually preferred to alloSCT due to its widespread availability, lack of the immunological problems intrinsic to the development of graft-versus-host disease (GvHD), and the infrequent bone marrow involvement present in HD patients undergoing high-dose chemotherapy/radiotherapy. AlloSCT has been associated with a high transplant-related mortality (TRM) in patients with HD due to a high incidence of GvHD and of fatal infectious events after transplantation. The poor outcome of these patients after alloSCT may reflect in part the advanced status of the disease at transplantation and the poor performance status of the patient population allografted. Furthermore, the high TRM present in t h e conventional alloSCT setting hasnever allowed a proper evaluation of a possible graft-versus-Hodgkin's effect. In an effort to reduce the TRM associated with alloSCT, low-intensity regimens have been developed; the curative potential of these protocols would rely on the graft-versus-leukemia effect of the allogeneic infusion more than in the conditioning regimen per se. Although the number of HD patients allografted with reduced-intensity protocols is low and the follow-up still short, TRM seems lower than in the conventional allograft setting despite a similar incidence of acute GvHD (aGvHD). Overall and progression-free survival seem promising, and patients developing aGvHD after transplantation or donor lymphocyte infusions seem to be at a lower risk of relapse than those not presenting this complication.