Background aims: The rising use of allogeneic transplantation in older recipients necessitates considering older related donors. The effect of related donor age for peripheral blood stem cell allografts (PBSC) on graft maintenance and outcomes, independent of CD34(+)cell dose, has not been well-characterized.
Methods: HLA-related donors (98% siblings) underwent a uniform filgrastim-based mobilization regimen aiming to collect and infuse 5 × 10(6) CD34(+) cells/recipient kg. Donor and recipient age were modeled in multiple ways to account for the correlation, and outcomes reported by decade of donor age.
Results: The median donor and recipient ages were 52 years and 54 years, respectively. The mean CD34(+) cell dose infused was 5.6 × 10(6) CD34(+)/kg and 75% of patients received a narrow range between 4.4 and 6.6 × 10(6) CD34(+) cells/kg. Neither better PBSC mobilization nor higher CD34(+) content of allografts was significantly associated with engraftment or transplant outcomes. After adjusting for recipient age and other prognostic factors, older donor age by decade conferred a lower risk of non-relapse mortality (NRM) [hazard ratio (HR) = 0.64, 95% confidence interval (CI) 0.45-0.91, P = 0.013] and borderline improvement in overall survival (OS) (HR = 0.76, 95% CI 0.58-0.99, P = 0.045) without altering progression-free survival (PFS) (HR = 0.85, 95% CI 0.66-1.07, P = 0.18).
Conclusions: Older donor age does not worsen outcome after matched related donor PBSC transplantation in patients receiving a narrow range CD34(+) cells. The relatively small sample size mandates that the finding of similar to improved outcomes for older related donor age must be confirmed in larger studies.