Correspondence: Andrew S. Artz, MD, MS, Section of Hematology-Oncology, 5841 S. Maryland Avenue, MC 2115, University of Chicago, Chicago, IL 60637, USA. E-mail: aartz@medicine.bsd.uchicago.edu (Received 19 December 2011; accepted 26 March 2012) Inﬂuence of related donor age on outcomes after peripheral blood stem cell transplantation ELIE M. RICHA 1 , RANGESH KUNNAVAKKAM 3 , LUCY A. GODLEY 2 , JUSTIN KLINE 2 , OLATOYOSI ODENIKE 2 , RICHARD A. LARSON 2 , VU NGUYEN 2 , WENDY STOCK 2 , AMITTHA WICKREMA 2 , KOEN VAN BESIEN 2 & ANDREW S. ARTZ 2 1 Biological Sciences Division, Department of Pathology, Section of Blood Bank and Transfusion Medicine, University of Chicago, Chicago, Illinois, USA, 2 Biological Sciences Division, Department of Medicine, Section of Hematology-Oncology, University of Chicago, Chicago, Illinois, USA, and 3 Biological Sciences Division, Department of Biostatics, University of Chicago, Chicago, Illinois, USA Abstract 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. Key Words: older age, recipients, related donors, transplant outcomes Cytotherapy, 2012; 14: 707–715 ISSN 1465-3249 print/ISSN 1477-2566 online © 2012 Informa Healthcare DOI: 10.3109/14653249.2012.681041 Introduction The use of allogeneic hematopoietic cell transplan- tation has increased rapidly among older adults because of reduced intensity conditioning, more tolerable immune suppression and better support- ive care (1). Sibling donors for older recipients will generally be older as well. The ready availability and safety of ﬁlgrastim-mobilized peripheral blood stem cell (PBSC) collection promotes collection of older and possibly less healthy donors (2–4) but very little is known about how donor age affects outcomes from related donor PBSC allografts. An early study by Kollman et al. (5) indicated that older donor age was associated with worse survival after unrelated bone marrow transplant, reinforcing the notion of the beneﬁts of younger donor age. A larger study integrating high-resolution HLA matching showed a non-signiﬁcant increase in mortality related to older donor age after unrelated bone marrow transplant (6). Older donor age correlates with reduced yields from marrow and PBSC harvests and may be a mechanism for the potential adverse effect of older donor grafts. For example, higher a total nucleated cell dose appears to reduce non-relapse mortality (NRM) and improve overall survival (OS) after bone marrow allografts (7). Compared with mar- row sources, dose issues related to age may be less problematic from PBSC grafts as more CD34 + cells are often obtained (8) and cell dose can be