Characteristics of thawed autologous umbilical cord blood

Autologous umbilical cord blood (AutoUCB) has historically been cryopreserved for potential use in hematopoietic transplantation. Increasingly, private AutoUCB banking is performed for therapies unavailable today. A Phase I trial using AutoUCB treatment for early pediatric Type 1 diabetes afforded us an opportunity to analyze characteristics of AutoUCBs.

Twenty AutoUCBs from AABB-accredited private cord blood banks (CBBs) were evaluated for collection, processing, cryopreservation, and thaw characteristics. Using a standardized thaw-wash method, AutoUCBs were assessed for viable total nucleated cells (vTNCs), viable CD34+ (vCD34+), and colony-forming unit-granulocyte-macrophage counts. Postthaw %vTNC recoveries were compared against processing characteristics and analyzed according to processing method, cryopreservation volume, concentration, container, and length of storage.

AutoUCB collection volumes (19.9-170 mL), cryopreserved TNC counts (7.6 × 10(7) -3.34 × 10(9)), %TNC processing recoveries (39%-100%), postthaw %vTNC recoveries (58%-100%), and %vCD34+ recoveries (26%-96%) varied widely. Regarding cell dose requirements, only 11% of evaluable AutoUCBs achieved the minimum TNC count of at least 9.0 × 10(8) to meet the National Cord Blood Inventory banking threshold, and only 50% met the minimum of 5.0 × 10(8) TNC count for Food and Drug Administration cord blood licensure eligibility. %vTNC recoveries correlated with %vCD34+ recoveries (R = 0.7; p = 0.03). Length of storage, cryopreservation volume, concentration, and container type did not affect postthaw %vTNC recoveries. CBB processing method, however, was associated with %vTNC postprocessing recoveries, with unmanipulated and plasma-depleted AutoUCBs having the highest postthaw %vTNC recovery, followed by RBC-depleted and density gradient-separated AutoUCBs.

The high variability and low counts found in AutoUCB banking suggest that further standardization of characterization, collection, and processing procedures is needed.