What Clinical Characteristics of Mothers and Babies Favorably Influence Cord Blood Potency? Defining Parameters That Can Guide Public Cord Blood Collection

Cord blood (CB) is a rich source of hematopoietic stem cells and provides access to transplantation for many patients who otherwise would not have a suitably matched donor. Numerous international public CB banks are actively accruing units to the public inventory. While public banking is an activity that benefits many patients by increasing access to hematopoietic stem cell transplantation, it is financially challenging to maintain operations of a public bank which must front all costs of inventory building and overall operations. It is well recognized that total nucleated cell (TNC) content as well as numbers of CD34⁺ and colony forming unit (CFU) cells define a superior cord blood unit (CBU). In the US, criteria defining a higher quality CBU have been established through the C.W. Bill Young Cell Transplantation Program's National Cord Blood Inventory. Applying current criteria, only ∼40% of collected CBUs meet criteria for banking. To improve the yield of “bankable” CBUs and allow for better focus of resources, we hypothesized that certain maternal/donor characteristics may be predictive of TNC (also, CD34⁺ or CFU) and, therefore, be more likely to meet banking criteria.

Between 9/07–7/09, CBUs donated to the Carolinas Cord Blood Bank (n=5282) and meeting criteria for public banking (n=5268) or identified for directed donation (n=14) were analyzed. Standard criteria for donor eligibility were followed, including gestational age >34 weeks, uncomplicated pregnancy and delivery, singleton birth, and maternal age ≥18 years. Technical characteristics were obtained as part of routine banking procedures (including post-processing TNC, CD34⁺ and CFU) and were correlated with clinical features of the mother and baby including maternal age, delivery type, baby gender, birth weight (BW), gestational age, race/ethnicity and collected CB volume. Univariate and multivariate logistic regression models were created dichotomizing for TNC, CD34⁺ and CFU content. Univariate and adjusted odds ratios are provided.

In this study cohort, the infant donors had a median gestational age and BW of 39.0 weeks (range, 34–42 weeks) and 3580g (range, 1800–5724g), respectively. Both genders were evenly represented although there were more Caucasian infants (58.9%) followed by African American (20.2%) and Hispanic (12.9%). Slightly more infants were born via vaginal delivery (59.8%) to mothers with a median age of 29 years (range, 18–53 years). The median TNC count was 11.7×10⁸ (range, 2.9–55.5), CD34⁺ cells were 3.36×10⁶ (range, 0.017–98.2) and CFU content was 34.0×10⁵ (range, 0.6–193.3). In univariate analysis, maternal/donor characteristics that were associated with high TNC (defined as a TNC of >10×10⁸) included Caucasian race [OR 1.29 (95%CI 1.14–1.46) p<0.0001], Caesarian delivery [OR 1.23 (95%CI 1.09–1.39) p<0.0001], higher gestational age [OR 1.16 (95%CI 1.10–1.22) p<0.0001] and BW>3500g [OR 1.86 (1.64–2.09) p<0.0001]. Conversely, African American race was a negative predictor of high TNC [OR 0.76 (95%CI 0.66–0.88) p=0.0002] while gender and Hispanic race were not significant. In multivariate modeling of TNC including maternal/donor characteristics, BW [>3500g; OR 1.75(95%CI 1.54–1.98) p<0.0001] was the best predictor of a high TNC followed by Caucasian race [OR 1.20(95%CI 1.06–1.36) p=0.004] and Caesarian delivery [OR 1.20 (95%CI 1.05–1.36) p=0.006). We also examined clinical variables predictive of a high CD34⁺ content (defined as >3×10⁶). In univariate analysis, male gender [OR 1.31 (95%CI 1.19–1.49) p<0.0001], BW>4000g [OR 1.93 (95%CI 1.66–2.25) p<0.0001], older gestational age [(OR 1.19 (95% CI 1.14–1.25) p<0.0001] and Caucasian race [OR 1.18 (95%CI 1.06–1.32) p=0.003] were predictive of high CD34⁺ content. Interestingly, neither maternal nor donor characteristics were associated with high CFU growth in univariate or multivariate analysis.

Maternal/donor characteristics are predictive of TNC and CD34⁺ in collected CBUs. However, no clinical characteristic predicted graft CFU content, the primary determinant of CBU potency. These associations could be used to prioritize donations, optimizing resource utilization and financial modeling. Of note, African American race was associated with lower TNC indicating that increased numbers of African American CBUs will need to be collected to achieve a robust inventory of higher quality units.

No relevant conflicts of interest to declare.