Viewpoint: What is the role of allogeneic haematopoietic cell transplantation in the era of reduced-intensity conditioning - is there still an upper age limit? A focus on myeloid neoplasia

Allogeneic haematopoietic cell transplantation (HCT) is the most effective curative therapy in acute myeloid leukaemia (AML) and myelodysplastic syndromes (MDS). Incidence of AML and MDS increases with age, peaking in the seventh decade. Despite improved Ara-C and anthracyclin-based chemotherapy regimens, the prognosis of AML in patients beyond 60 years of age is dismal. The introduction of peripheral blood-derived stem cell grafts into allogeneic HCT and the known antileukaemic effect of donor lymphocyte infusions paved the way for reduced-intensity conditioning (RIC) allogeneic stem-cell transplantation, which makes transplant in advanced age possible and significantly reduces transplant-related organ toxicity and mortality. The success of RIC HCT relies on the alloreactivity of the donor immune system and the graft-versus-leukaemia effect. We try to answer the following questions in this paper: who should receive RIC HCT? when and how should the transplant be performed? is there an upper age limit and what is the future of RIC HCT?.