Cord Blood Banking

Advantages

CB is a rich source of HSC and can be collected easily, without risks to the mother or the newborn baby.

• There are large numbers of donors from all ethnic backgrounds increasing the chances of minority patients to find a suitable donor.

• There are advanced techniques for processing and storing the CBU in large Inventories, with currently no established “expiration date”. Since all testing has been completed, cryopreserved CB is an “off-the-shelf” product and can be sent to the transplant centers upon demand, so that patients can be treated without any delays.

• There is a lower risk of viral infections of the newborn babies, particularly those relevant to transplantation (such as cytomegalovirus – CMV), in comparison to adult volunteer donors.

• CB contains immunologically “naïve” or “different” T cells; as a result, transplants can be performed without “perfect” HLA matching between donor and recipient with acceptable incidence of graft-versus-host disease. The ability to use partially matched CB grafts increases significantly the probability of finding suitable donors for patients.

Considerations

The volume and number of total nucleated cells (TNC) contained in a CBU is defined at the time of collection. TNC dose (TNC/kg body weight of recipient) may not be adequate for larger patients. The donor cannot be approached for a second donation.

• There is a potential risk for transmission of (unknown) genetic diseases.

Recommendations

The American Academy of Pediatrics (AAP) policy in 2017 states that “ public CB banking is the preferred method for collecting, processing and using CB cells for transplantation .” Additionally, “ quality-assessment reviews by several national and international accrediting bodies show private CB banks to be underused for treatment, less regulated for quality control, and more expensive for the family than public CB banks .” The American Society of Blood and Marrow Transplantation (ASBMT) presented similar recommendations in 2008, encouraging directed donations in certain clinical situations and public cord blood donations, where possible.

Collection

The collection process involves harvesting of CB, obtaining maternal informed consent for donation and maternal blood sample for testing, review of maternal medical records, and completion of the maternal questionnaire to evaluate donor risk factors.

CB can either be collected in utero, during the third stage of labor, after the delivery of the baby, a method performed usually by the obstetrician or obstetrical staff, or ex utero, after the third stage of labor and delivery of the placenta, with the placenta suspended from a stand, usually performed by trained collection personnel. With either method, careful cleaning of the venipuncture site on the umbilical cord is important to avoid bacterial or maternal blood contamination. CB flows by gravity into a blood collection bag containing anticoagulant (CPDA). To maximize collection volume and avoid clotting, timing of the CB collection in relation to the delivery of the placenta is critical. Further, the volume of CB that can be collected for banking is influenced by several variables, such as the infant’s birth weight and gestational age, as well as the amount of placental transfusion, i.e. how much blood is allowed to go to the newborn before clamping the umbilical cord. The recent practice of “delayed” cord clamping after birth has imposed challenges in the collection of sufficient CB volumes for banking and clinical transplantation.

Processing

The aim of processing (minimal manipulation) is to reduce the cell volume to be frozen, by removing the bulk of RBCs and plasma. Today automated processing systems are used, which require less time and processing occurs in a closed system reducing the potential for product contamination. The two systems most commonly used by CB banks are AXP (AutoExpress, Thermogenesis, CA, USA) and Sepax (Biosafe, Switzerland). Automated processing results in products with lower hematocrit and predefined volume. The final mononuclear cell product is in the cryopreservation (freezing) bag. The bags can have one or two compartments and “segments” i.e., internally attached tubing, that contains small amounts of product. Cells from the segment can be used for testing prior to the release of the CBU for transplantation.

Cryopreservation

Cryopreservation is performed by addition of the cryoprotectant dimethyl sulfoxide (DMSO) to a final concentration of 10% with continuous mixing while maintaining the product temperature between 0 and 4°C. According to NETCORD-FACT standards the time interval from the CBU collection to processing must not exceed 48 hours.