© F e r r a t a S t o r t i F o u n d a t i o n 2 0 1 3to donate PBSC a second time. This may simply be a reflection of changing trends in hematopoietic progenitor cell harvest (PBSC harvest has become much more common in recent years) 1 , or may reflect the view that transplantation with peripherally harvested stem cells carries a lower risk of graft failure. 24 By contrast, little work has been published looking at donor attributes at first donation that may be associated with an increased likelihood of being requested to give a subsequent HPC donation. One study from the United Kingdom of 144 patients diagnosed with primary graft failure following transplantation suggested that the use of BM as the HPC source, female donors and HLA-mismatched grafts increased the risk of primary graft failure (and, consequently, a request for a subsequent donation). 25 In order to develop the evidence, and provide a sounder base for informed consent from its own unrelated donors, Anthony Nolan undertook a study of all second donations made by its HPC donors from 2005 to 2011. The objectives were to identify those donor and patient characteristics known by the registry at first donation that may be associated with a subsequent request for another HPC donation, to examine the safety of subsequent donations, and to compare harvest yields between first and subsequent donations. Importantly, this study was not aimed at examining patient factors predictive of the need for a second allograft.
Methods
Data collectionData were obtained retrospectively from records kept by Anthony Nolan for the period 2005-2011, during which time 2591 HPC donations were made by 2472 unrelated adult donors to 2493 recipients.During this study period, 145 requests for subsequent donations were made, of which 25 (17.4%) were later cancelled by the transplant center. There were three types of subsequent donation requests encountered in this study: 118 requests (group A, 81.4%) were to the same donor for the same patient as the initial donation; 21 (group B, 14.5%) were to a donor who had previously donated, but for a different patient and in six cases, patients requested (group C, 4.1%) a subsequent donation from a different donor.For the purposes of assessing an association between donor and patient characteristics at initial donation and the need for a subsequent donation (whether from the same or a different donor), all patients for whom there was a request for a subsequent donation were reviewed (i.e. excluding those donors in group B whose donations were being used for a first transplant for the recipient). For the purposes of assessing harvest yields and adverse events related to a second donation, all donors who had donated more than once were reviewed (i.e. excluding the group C donors who had donated only once).Thirteen (8.9%) of the donors who made a subsequent donation during the study period made their initial donation before 2005. As the statistical analysis relied on comparator data from those donors who made only a single donation, ...