Related peripheral blood stem cell donors experience more severe symptoms and less complete recovery at 1-year compared to unrelated donors.

Unlike unrelated donor registries, transplant centers lack uniform approaches to related donor assessment and deferral. To test whether related donors are at increased risk for donation related toxicities we conducted a prospective observational trial of 11,942 related and unrelated age 18-60. Bone marrow was collected at 37 transplant and 78 National Marrow Donor Program centers and peripheral blood stem cells were collected at 42 transplant and 87 unrelated donor centers in North America. Ascertainment of medical comorbidities occurred prior to donation and standardized pain and toxicity measures were assessed pre-donation, peri-donation, and one year following. Multivariate analyses showed similar experiences for marrow collection in related and unrelated donors, however, related stem cell donors had increased risk of moderate (OR 1.42, p<0.001) and severe pain (OR 8.91, p<0.001) and toxicities (OR 1.84, p<0.001) with collection. Related stem cell donors were at increased risk of persistent toxicities (OR 1.56 p=0.021) and non-recovery from pain (OR 1.42 p=0.001) at 1 year. RD with more significant comorbidities were at especially high risk for grade 2-4 pain (OR 3.43, p<0.001) and non-recovery from toxicities (OR 3.71, p<0.001) at 1 year. Related donors with more significant comorbidities were at especially high risk for grade 2-4 pain (OR 3.43, p<0.001) and non-recovery from toxicities (OR 3.71, p<0.001) at 1 year. Related donors reporting grade ≥2 pain had significant decreases in HR-QoL at 1 month and 1 year post-donation (p=0.004). Conclusion: related peripheral blood stem cell donors with comorbidities are at increased risk for pain, toxicity, and non-recovery at 1 year after donation. Risk profiles described in this study should be used for donor education, planning studies to improve the related donor experience, and decisions regarding donor deferral. Clinicaltrials.gov NCT00948636.