The role of repeat transplantation of haemopoietic stem cells and adoptive immunotherapy in treatment of leukaemia relapsing following allogeneic transplantation

Recurrence of disease is still one of the most important causes of treatment failure in patients with acute or chronic leukaemia given an allogeneic transplant of haemopoietic stem cells (HSC) and presents the haematologist with a formidable therapeutic challenge. In fact, optimal management of transplant recipients experiencing leukaemia relapse is one the most controversial issues, and the approach for each individual patient depends on his/her or family's wishes, time interval between transplant and recurrence, and careful evaluation of the possibilities of definitive cure. The median survival time of patients relapsing after an allograft is only 3-4 months if no further treatment is administered (Frassoni et al, 1988). Palliative or even intensive chemotherapy in patients with acute leukaemia, and or-interferon treatment in patients with chronic myeloid leukaemia (CML) relapsing after an allograft, can at best control the disease for some time, but cannot eradicate the malignant population (Mehta ct al, 1997; Arcese et al, 1990). The only strategies demonstrated to be potentially able to definitively cure patients experiencing a recurrence after an allogeneic transplant of RSC are second transplant and infusion of donor-derived leucocytes (DLI).