Cord Blood Processing

Cord blood is used in transplantations to replace diseased cells of the blood or immune system. Cord blood is also being infused in clinical trials as a regenerative medicine.

In cord blood transplantations, it has been shown that more stem cells are often associated with a faster recovery of the patient’s immune system, a vital component of recovery. When infused as a regenerative treatment, more stem cells are also associated with better outcomes.

There are only a couple of things parents can do to ensure that they get the highest number of stem cells from their baby’s umbilical cord:

1. Work with your doctor to capture as much cord blood as possible.
2. Choose a cord blood bank that has a good processing method.

Work with your doctor

Every cord blood collection is different and even smaller collections can contain more stem cells than larger collections; however, in general, the more cord blood obtained, the more stem cells it will contain. As a parent, you’ll want to ask your doctor to capture as much cord blood as possible.

It is also important for the cord blood to be collected before the placenta has been delivered. Collections made before the placenta has been delivered have significantly higher volumes and many more stem cells than collections performed after the placenta has been delivered.¹ Ensure your doctor will be ready to collect the cord blood before the placenta is delivered.

There are many things outside the mother’s control that can also affect the size of the cord blood collection including premature labor, placenta collapse, and other delivery complications. Parents who choose delayed cord clamping may also capture less cord blood.

Research the different cord blood processing methods

There are four different processing methods available, and they are not equal. Let’s review each method and help you decide which one is best shown to capture the most stem cells.

Hydroxyethyl starch

The majority of cord blood banks in the U.S. and Canada process their cord blood manually with hydroxyethyl starch. It is used by Americord, Cryo-Cell, LifebankUSA, StemCyte and Viacord. It is commonly referred to by its brand name Hespan or shortened to the acronym HES. The cord blood is placed in a centrifuge to separate its components into layers. Hydroxyethyl starch helps better define that separation, allowing the stem cells to be easily extracted.

AutoExpress (AXP)

AutoExpress (AXP) is used by Cord Blood Registry and the New York Blood Center, a public cord blood bank. As AXP is a device that separates and isolates the stem cells, it is called an automated processing method. The device isolates and moves the stem cells from a cord blood collection into a storage container.

Automated methods are not often affected by human error, but each collection is treated uniformly, and the process cannot be customized for the specific collection.

PrepaCyte-CB

PrepaCyte-CB is an reagent from Cryo-Cell International. PrepaCyte is an enhanced method that more efficiently separates cord blood into its different parts. As a result, PrepaCyte-CB can recover 72%–88% of stem cells compared to 58%–80% when using hydroxyethyl starch. PrepaCyte can also remove 99% of red blood cells compared to 75% for Hetastarch.²

Sepax

Sepax is used by Duke University Medical Center and cord blood banks like Evercord and Caricord. As the device, and not a technician, separate and isolate the stem cells, it is also an automated processing method. Like AXP, the Sepax device removes the red blood cells and other unnecessary components and moves the stem cells into a storage container.

Comparing the two automated methods, Sepax was shown to capture more stem cells than AXP (78% vs. 76%). Both methods reduced the number of red blood cells by around 88%.³

Both AXP and Sepax automated methods have a tougher time capturing stem cells from larger collections, and the percentage of stem cells Sepax can collect in large collections can go as low as 62%.⁴

Other processing methods

Some banks have names for the way they handle or collect cord blood.

Americord’s Cord Blood 2.0 uses a placental stand and gravity to capture more cord blood. Gravity is a factor affecting the total volume of cord blood collected; however, there are factors that can affect its correct use: Doctors are more accustom to performing cord blood collections before delivery of the placenta. The use of a stand after the delivery of the placenta requires proper training, additional time and extra support staff to be properly carried out. Parents should check with their doctors to make sure they are able to effectively perform the procedure. In addition, the placental stand is not allowed in the operating area for C-sections because of sterility requirements.

StemCyte’s MaxCell retains all the red cells in addition to the buffy layer containing the stem cells and white blood cells; it does not separate and isolate the stem cells like other methods. The process is commonly referred to as the plasma-depletion method.

Plasma-depleted cord blood has been shown to contain 20%–25% more stem cells than cord blood units processed with hydroxyethyl starch and about the same as those processed with PrepaCyte-CB or Sepax.⁵ Because of the very nature of the processing method, plasma-depleted cord blood also contains red blood cells. As adverse reactions can occur across blood types, transplantations with red blood cells need to be handled specially. Red cells may also decrease post-thaw viability of the stem cells, and the removal of red cells post-thaw may eventually be necessary,

Processing methods and patient recovery

The time to patient recovery is a vital following a transplantation because of the patient’s weakened immune system. The FDA has released information on patient recovery times using a couple of different methods for processing cord blood:

The cord blood product from Duke University Medical Center processed using Sepax took a median of 21 days for patients to recover⁶; on the other hand, the cord blood product from the New York Blood Center processed using AXP took a median of 20 days for the patients to recover.⁷

These can be compared with other published patient recovery times where hydroxyethyl starch took 20 days to engraft and PrepaCyte-CB took the fewest days of all at 16 days.⁸

Recommendations

PrepaCyte-CB can easily be recommended because it provides a very “clean” cord blood product and can help patients get better faster. It is also effective with small and large collections alike. The Sepax device would be our second pick after PrepaCyte-CB; it can also utilize Hestarch to help recover more stem cells, but it is not as effective with the large cord blood collections. AXP falls behind Sepax in comparison and may not always outperform HES. While HES may not seem to be as effective as other methods, it has proven itself in the field and through thousands of transplantations.

Sources:

(1) Shpall, E. J., Karandish, S., Sadeghi, T., Hosing, C., Garcia, C. J., Cherry, M. T., . . . McMannis, J. D. (2006, November 16). In Utero Is Superior to Ex Utero Cord Blood Collection. Retrieved from http://www.bloodjournal.org/content/108/11/3645
(2) Regan, Donna. (2008). Retrieved from www.celltherapysociety.org/resource/resmgr/files/PDF/Publications/TelegraftWinter2008.pdf
(3) Solves, P., Planelles, D., Mirabet, V., Blanquer, A., & Carbonell-Uberos, F. (2013, July). Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3729132/
(4) Improving umbilical cord blood processing to increase total nucleated cell count yield and reduce cord input wastage by managing the consequences of input variation. (2014, November 06). Retrieved from https://www.sciencedirect.com/science/article/pii/S1465324914007853
(5) Young, W. (n.d.). Plasma-depleted versus red cell-reduced umbilical cord blood. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/24816442
(6) FDA.gov. (n.d.). Retrieved August 20, 2018, from https://www.fda.gov/downloads/BiologicsBloodVaccines/CellularGeneTherapyProducts/ApprovedProducts/UCM322732.pdf
(7) FDA.gov. (n.d.). Retrieved August 20, 2018, from https://www.fda.gov/downloads/BiologicsBloodVaccines/CellularGeneTherapyProducts/ApprovedProducts/UCM279612.pdf
(8) St. Louis Cord Blood Bank (n.d.). Retrieved July 1, 2018, from http://www.slcbb.org/blog/Documents/Abstract Poster Prep vs. Hes 2017-final.pptx