The recent study, published in Transfusion, analyzed the quality of autologous cord blood (CB) samples. This study has sparked some discussion among professionals. I think, this analysis is unique and significant. Because the article published in “closed access”, I’ll briefly summarize and cite some data below.
20 autologous cord blood samples stored in private banks, which were used in children with type 1 diabetes enrolled in the clinical trial. Samples were collected between 1996 and 2005 in 9 AABB-accredited private cord blood banks. Median length of storage was 5.5 years.
CB characteristics assessed:
volume, viability, total nucleated cell (TNC) count, CD34+ cell count, colony-forming assay (CFU);
time points: at collection, cryopreservation (post-processing), post-thawing
Mean volume of CB samples – collected: 62.87 ml, cryopreserved: 37.5 ml, sent for infusion: 27 ml.
Mean TNC number – collelcted: 10.12 x 108, cryopreserved: 6.99 x 108, received for infusion: 5.1 x 108, post-thaw: 4.01 x 108.
Only 2 of the 18 (11%) evaluable AutoUCBs met the current NCBI threshold of 9.0 × 108, TNC for banking. Only 9 of the 18 evaluable AutoUCBs had banked cryopreservation TNC counts of more than 5.0 × 108, the TNC count eligible for FDA cord blood licensure.
Only 9 out of 20 CB samples contained cryopreserved CD34+ cell count. The mean number of CD34+ cryopreserved 2.98 x 106, sent for infusion 2.4 x 106, post-thaw 1.97 x 106.
None of 9 banks reported CFU counts for auto CB samples.
Only 11% of of cryopreserved and 6% of post-thaw samples would have met the minimal recommended transplant dose for 40 kg. recipient.
The quality of autologous CB stored in private banks is low. Further improvement of collection, processing, product characterization and standardization are needed.
- This is the second study evaluating the quality of autologous CB for personal use. In contrast to Duke’s study, CB samples stored only in private banks were evaluated. Both studies reported low quality of privately stored CB. But the result of these studies is not a big surprise, because we would expect lower quality of CB samples stored in private banks. The authors nicely summarized:
A distinction between private AutoUCB and public allogeneic cord banking is the AutoUCB reduced collection volume and TNC count banking threshold. The overriding concept in AutoUCB banking is that the product is irreplaceable and should be banked accordingly, often regardless of collection volume or TNC count. Public cord banks, by contrast, set minimal acceptable collection volumes and TNC counts for banking, based on expected engraftment outcomes for use in hematopoietic transplant and immune reconstitution. As a result, public cord banking rates are expectedly lower, with products not meeting minimal standards being discarded.
- The samples, analyzed in the study, had a great variability in collection period, volume, processing methods and protocols. For example, it’s hard to compare CB stored in 1996 and in 2005, because CB processing methods were developed rapidly in the last decade. So, for solid conclusions we need more data, greater number of samples from the same cohorts (same processing method, same standards, same period of time).
- The most important conclusion, in my opinion, that the lower quality of autologous CB samples could compromise the results of clinical trials. It is very important issue in the era of cord blood use for regenerative medicine applications. Would physician reject the family’s CB sample based on low volume or TNC count? The family was paying for this “big moment”! I assume, in such trials all or most of the patients get enrolled, irrespective of the quality of stored personal CB. That’s could be one of the reasons for doubtful results or failures of such trials.
- Obviously, private CB banks should work hard on improvement of quality, characterization and standardization of stored samples. Especially if they are planning to play in “regenerative medicine game”.