Impact of donor age on outcome after allogeneic hematopoietic cell transplantation

As older patients are eligible for allogeneic hematopoietic cell transplantation (HCT), older siblings are increasingly proposed as donors. We studied the impact of donor age on the tempo of hematopoietic engraftment and donor chimerism, acute and chronic graft-versus-host disease (GVHD), and nonrelapse mortality (NRM) among 1174 consecutive patients undergoing myeloablative and 367 patients undergoing nonmyeloablative HCT from HLA-matched related or unrelated donors with granulocyte colony-stimulating factor-mobilized peripheral blood mononuclear cell allografts. Sustained engraftment rates were 97% and 98% in patients undergoing myeloablative and nonmyeloablative conditioning, respectively, for grafts from donors < 60 years old (younger; n = 1416) and 98% and 100%, respectively, for those from donors ≥ 60 years old (older; n = 125). No significant differences were seen in the tempo of neutrophil and platelet recoveries and donor chimerism except for an average 1.3-day delay in neutrophil recovery among myeloablative patients with older donors (P = .04). CD34(+) cell dose had an independent effect on the tempo of engraftment. Aged stem cells did not convey an increased risk of donor-derived clonal disorders after HCT. Myeloablative and nonmyeloablative recipients with older sibling donors had significantly less grade II to IV acute GVHD than recipients with grafts from younger unrelated donors. Rates of grade III and IV acute GVHD, chronic GVHD, and NRM for recipients with older donors were not significantly different from recipients with younger donors. In conclusion, grafts from donors ≥ 60 years old do not adversely affect outcomes of allogeneic HCT compared with grafts from younger donors.