Apheresis and transplant of hematopoietic progenitor cells (HPC) from allogeneic donors of age above 60 years

Abstract

Over the immediate past 4 years, our program has collected hematopoietic progenitor cells by apheresis from 48 individuals aged 61 and over (range 61–71 years of age). We have retrospectively analyzed the collection and transplant results associated with employing these donors, and have compared them with 175 donors aged 60 or less who were collected during the same time period. We have found no significant difference in venous access (P=0.208), rate of post-transplant engraftment of neutrophils (P=0.117) and platelets (P=0.692), or in rate and grade of acute GVHD (P=0.806). However, we have found that these older donors have a significantly lower mobilization of CD34+ cells as reflected in lower absolute counts of circulating CD34+ cells pre-apheresis (P=0.016). This, in turn, results in lower CD34+ cell yields in apheresis products (P<0.001), trending towards requiring more apheresis procedures (22.9 vs 13.7%, P=0.095) to collect sufficient CD34+ cells for transplantation. We conclude that it is practical when necessary to employ donors aged 60 and above, as well as safe for both donor and intended recipient. However, concern over reduced CD34+ cell mobilization may be sufficient grounds to seek younger donors when possible.