1 Introduction

Umbilical cord blood (UCB) cells for allogeneic use are collected and frozen in more than 160 public CB banks worldwide. More than 800,000 CB units (CBUs) are available for transplantation. In this chapter, we will describe some procedures for cord blood collection, processing, banking, and recommendations on how to choose a single or double UCB unit for transplantation (Querol et al. 2021).

2 Collection

During the antenatal period, objective information on the opportunity to donate UCB is given by trained health care providers. After consent, qualified personnel determines donor eligibility to ensure that donation is safe for future recipients. To assess donor eligibility, a donor questionnaire and a medical history review are conducted for identifying risk factors for transmissible and genetic diseases. In addition, infectious disease markers (IDMs) are tested on maternal blood samples obtained within 7 days before or after the collection of the UCB unit. According to local regulations, IDMs are assessed for evidence of infection by HIV-1, HIV-2, hepatitis B, hepatitis C, HTLV-I, HTLV-II, syphilis, and any additional markers required.

Collection technique must not interfere with maternity hospital regular delivery care. Successful collection aims having a high volume that correlates with higher cell contain, avoiding microbial contamination and ensuring traceability. High-quality CBUs are compatible with delayed cord clamping usually up to 1–2 min (Frändberg et al. 2016). After cord clamping, thorough disinfection, venipuncture of umbilical vein to drain by gravity into a primary container containing anticoagulant to avoid clotting. Collection bag and accompanying maternal samples shall be appropriately labeled.

There are two main techniques to collect UCB: before the placenta is delivered (in utero) or after the placenta is delivered (ex utero). Both collection techniques are equivalent regarding quality, providing that collectors are adequately trained and the procedure is validated in each collection center.

After collection, collector will complete a report describing labor characteristics and informing on incidences like the presence of fever or other complications, type of delivery, drugs administered, etc. In case of unexpected adverse reactions during collection, they need to be communicated to the competent authority. After collection, it is advisable to follow-up the donor including health questionnaires. Additionally, if any abnormal result is detected during testing, a counseling process should be in place.

Once collection is finished, samples are locally stored in validated conditions before transportation to the processing center. As this facility may be far away from the collection sites, a validated procedure for transportation between these two facilities is needed to demonstrate a controlled environment. Standard operating procedures shall be in place to describe time and temperature of storage and transportation methods. All transportation records shall allow tracking back from the collection site to the UCB bank, and any deviation should be recorded.

3 Processing and Banking

3.1 UCB Cell Processing

Unrelated UCB unit must arrive at the processing laboratory in time to allow initiation of cryopreservation within 48 h of collection (this time is extended to 72 h for related or directed UCB donations). The decision as to whether a collected UCB unit will be acceptable for processing and banking will be made based on the acceptance criteria specified by the UCB bank. Many banks have further refined their acceptance criteria based on economics and the desire to build an international inventory of high-quality UCB units with very high TNC or shifted toward ethnic minorities. Many UCB banks are now committed to processing and storing only those UCB units with high TNC (e.g., >150 × 107 TNC or higher), based on the greater likelihood of these units being used (Saccardi et al. 2016).

Once accepted for further processing, volume reduction of UCB is considered essential to the provision of a high-quality product and cost-effective UCB banking. Reducing the volume of the final product depleting of plasma and RBC allows for storage efficiency in terms of space and cost and, most importantly, reduces the risk of ABO incompatibility and DMSO toxicity to the potential recipient. Despite some cell losses, volume reduction has additional practical and clinical benefits; the process yields RBC and plasma components as waste products that can be used for immediate or future testing, thereby minimizing the loss of the actual stem cell product for testing purposes. Volume reduction is mainly performed by centrifugation using automatic devices and adding some macromolecules to improve buffy coat like hydroxyethyl starch.

The selection of a suitable protocol for cryopreservation of UCB for use in transplantation is critical to optimize the recovery of functionally viable progenitor cells, most of which lie within the CD34+ compartment. Some important considerations that are potential sources of cell damage include the type and concentration of cryoprotectant, the cell concentration, and the cooling and warming rates. UCB units must be stored in freezing bags designed and approved for the cryopreservation of human cells and placed into metal canisters to afford protection during freezing, storage, transportation, and shipping. It is important that after filling, each freezing bag is visually examined for possible leaking and breakage of seals.

UCB units should be cryopreserved using a controlled rate freezer with a validated freezing program. Liquid nitrogen-based tanks have been used to ensure long-term maintenance. Minimizing transient-warming events is very important to maintain viable cells. Stability programs should be designed in order to establish the expiration time of the UCB stored.

3.2 Testing and Quality Assessment

Table 18.1 shows release specification for UCB units. Quality assessment is written below:

Table 18.1 Lists the specification requirements for CBU stored for clinical application, according to appendix V of the seventh edition NetCord-FACT International Standards for Cord Blood Collection, Banking, and Release for Administration (www.factwebsite.org)
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3.2.1 Safety

It is essential that UCB is screened for those infectious diseases which can be transmitted via blood (as described above). In addition, product should be free of microbial contamination (or with an appropriate antibiogram for related uses). Prior to release for administration, each UCB unit must have undergone hemoglobinopathy screening.

3.2.2 Identity

At least, HLA-A, HLA-B, HLA-C, and DRB1 loci must be determined using DNA-based methods and result included when listing a UCB unit on the search registries. It is recommended that HLA typing is performed in an accredited laboratory. ABO blood group and Rh type must be reported prior to listing a UCB unit for search. Prior to the release of a UCB unit for administration, it is imperative that HLA identity is confirmed. Ideally, confirmatory typing will be performed on a sample taken from a contiguous segment. HLA typing on maternal blood may also be performed prior to release of a UCB unit. Haplotype matching between maternal donor and infant donor confirms linkage between the two and serves as a secondary confirmation of identity.

3.2.3 Purity

UCB unit specifications report total nucleated cells, total nucleated RBC count, and CD34+ cells, and a cell blood count with differential should be performed, with parameters for neutrophils, lymphocytes, monocytes, and platelets defined.

3.2.4 Potency

Potency testing to determine the growth potential and viability of progenitor cells in a UCB unit should be performed post-processing (prior to cryopreservation), in addition to being performed on a representative thawed sample prior to release for administration.

4 Selecting CBU for Transplantation

The success of the UCB transplantation (UCBT) will depend on the characteristics of the CBU. Tables 18.2 and 18.3 list the recommendation for selection of single and double cord blood units, respectively, for allogeneic transplantation.

Table 18.2 Recommendations for unrelated CBU selection and transplantationa
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Table 18.3 Additional criteria for double CBU selection
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Key Points

  • Cord blood donation comprises the following steps: informative and consent process, revision of eligibility criteria, cord blood collection, and finally fresh storage before a standardized transportation to the processing cell lab.

  • Cell processing labs require coordination of production and quality control labs to transform the altruistically donated raw material in a medicinal product with predefined specifications that ensure its safety, identity, purity, and potency.

  • A public cord blood bank is a stem cell registry that provides ready-to-use banked medicinal products for any patient in need through international networking of stem cell donor organizations.

  • Cord blood selection is based on sorting CB units using primary criteria (cell content at cryopreservation and HLA matching, based on allele level matching and including HLA C match) followed by ranking based on secondary criteria depending on the type of disease, disease status, conditioning regimen, patients age, and weight.