The Donor – Recipient Weight Ratio is a Reliable Marker for Cell Yield in Hematopoietic Stem Cell Donations

Bone marrow transplants remain an import source of hematopoietic stem cells for patients suffering from specific diseases like aplastic anemia, for pediatric patients with malignant and non-malignant blood cell disorders, and for situations in which graft-versus-host disease (GvHD) is a concern. Identifying the optimal donor to achieve a 3-5 x 108/kg of recipient weight TNC yield may be challenging. In an analysis of 687 consecutive donors, donor and procedure characteristics were related to TNC/kg of recipient weight using Spearman correlation coefficients as well as linear and multiple regression analysis. We found correlations between donor WBC (r = 0.17), donor platelet counts (r = 0.15), donor BMI (r = 0.10), and the percentage of donor estimated blood volume accessed for harvesting (r = -0.57) with TNC/kg of recipient weight. The strongest correlation existed between the donor-recipient weight ratio and the TNC/kg (r = 84). In a multivariate regression analysis, the donor-recipient weight ratio influenced the TNC/kg of recipient weight more significantly (adjusted R2 = 0.84) than all other related variables put together. The minimal donor-recipient weight ratio associated with a TNC/kg of at least 3x108/kg of recipient weight was 0.8 (mean 3.425; 95% CI 2.01, 5.8). Using this donor-recipient ratio provides national bone marrow donor registries with a practical and simple measure to assure optimal cell yield outcomes in hematopoietic stem cell donations.