Singapore

Zhu Pengcheng

In 1988, the medical world witnessed a groundbreaking procedure that marked a turning point in the history of medical treatments. A 5-year-old boy suffering from Fanconi anaemia in the USA became the first-ever recipient of a cord blood transplant (CBT). This watershed moment ushered in a new era, enabling CBT to evolve and establish itself as a mainstream strategy for treating over 80 diverse medical conditions. Since that pioneering procedure, CBT has been successfully performed over 40,000 times globally.

Rich in haematopoietic stem cells (HSCs), cord blood has proven to be a veritable treasure trove of life-saving potential. Cord blood has an excellent tolerance for human leukocyte antigen (HLA) mismatches. This flexibility makes it possible to perform transplants even when a perfect match is unavailable. Furthermore, cord blood carries a low risk of triggering graft-versus-host disease, a severe and potentially life-threatening complication that can occur after a transplant. As a result, CBT could have lower long-term healthcare burden than other HSC sources such as peripheral blood stem cells or bone marrow. Lastly the process of collecting cord blood is simple and non-invasive.

The Role of Cord Blood Banks

Playing a pivotal role in enabling transplants are cord blood banks (CBBs). Worldwide, nearly 450 CBBs are the custodians of more than 8.8 million CBUs, ready for transplantation. This may seem like a large number, but the reality is that many patients, particularly those from ethnic and racial minorities, are unable to find a compatible donor. To improve the quality of service, international accrediting bodies such as the Foundation for the Accreditation of Cellular Therapy (FACT) and the Association for the Advancement of Blood & Biotherapies (AABB) have proposed comprehensive guidelines for auditing CBBs.

The Benefits of Cord Blood

Cord blood boasts several unique advantages in transplant medicine. Providing a non-invasive source of stem cells is significant as it eliminates the need for a surgical procedure. Additionally, the flexible HLA requirements of cord blood often accelerate the finding of a suitable donor. This benefit is particularly pronounced for patients from racial and ethnic minorities, who frequently face difficulty finding a match in existing donor registries. The low CD34⁺ cell count per CBU has traditionally limited its use to paediatric patients, who require fewer cells for a successful transplant. However, recent advances in cord blood transplantation, such as double-unit CBT strategies and FDA-approved cord blood stem cell expansion techniques, have made it possible to use cord blood for adult patients as well.

Transplantation Rates and Economic Viability

Cord blood banking emerged in 1993, and there are two main models: public and family banking. It is noteworthy that over 80% of CBUs are stored in family banks. Family cord blood banking provides a distinct advantage by preserving a valuable resource that holds immense potential for personalized treatments and therapies.

By opting for family cord blood banking, families gain the exclusive benefit of securing a genetically matched source of stem cells. This aspect becomes particularly significant in the treatment of various diseases and conditions. Family banks offer increased accessibility and greater compatibility, ensuring a higher likelihood of finding a suitable match when the need arises.

The accumulation of cord blood units in family banks has steadily grown, reflecting the recognition of its long-term benefits. These stored units serve as an invaluable resource for potential future medical advancements and breakthroughs.

For public cord blood banks, the rates of transplant and the economic viability of cord blood banking are vital aspects to consider. For example, in regions like Hong Kong and China, the transplantation rate is very low at 1.4 per 10 million people, compared to other developed countries. From an economic perspective, a U.S. 

study estimated the societal benefit of public cord blood banking, based on the potential increase in life expectancy from CBT, to be a wide range, between USD 5 million and 1.5 billion per year. This contrasts with the yearly operational costs of cord blood banks, estimated to be between USD 60-70 million.

Community Banking Campaign

Data from multi-national studies indicate that in countries like the USA, UK, India, Japan, and South Korea, the probability of locating a 4/6 HLA-match cord blood unit for transplant is nearly 100% when the inventory size reaches 100,000 units. This suggests that expanding the number of available cord blood units can significantly increase the likelihood of finding a suitable donor for those in need. Notably, community banking, a new and flexible banking model, has been proposed as a way to benefit both society and individuals. In this model, a Community Banking Unit is primarily reserved for use by the donor family, but it can also be made available to other community bankers with the donor's consent. A centralized regulatory agency is essential for enforcing operational rules, promoting public awareness, and facilitating community engagement in biobanking.

Addressing Challenges

Despite the apparent benefits of cord blood, challenges persist. These include a lack of public awareness and willingness to participate in cord blood banking. This can be attributed to factors such as employment status, level of education, and understanding of the potential benefits of cord blood transplantation. Other contributing factors include the lack of regulatory oversight, the cost of banking cord blood, and concerns about the safety and efficacy of cord blood transplants.

Addressing these challenges is of paramount importance. Efforts to increase public and clinician awareness about cord blood's potential benefits and applications are necessary. Regulatory oversight needs to be enhanced to ensure cord blood's safe and effective use. The cost of cord blood banking should be reconsidered, and a fair and sustainable funding structure should be established.

Looking Ahead

In addition to facilitating transplants, cord blood banks are a rich resource for producing HLA-typed and virus-screened cellular starting material to produce induced pluripotent stem cell (iPSC) lines. These lines, created from mature cells that have been genetically reprogrammed to an embryonic stem cell-like state, have a wide range of potential applications in allogenic cell therapy. Researchers are now working diligently to establish internationally standardized haplo-lines, which could serve as a source of cell products for clinical research and personalized medicine.

Cord blood-derived cellular therapies in oncology are a promising area of development. By harnessing the power of cord blood stem cells, we could develop new treatments for various forms of cancer. Moreover, scientists are exploring cord blood hematopoietic cell transplantation modifications to improve its effectiveness and safety for personalised regenerative medicine.

In conclusion, the journey of cord blood transplantation from its first procedure in 1988 has been long and eventful. It has faced and continues to face numerous challenges, including technical issues, regulatory hurdles, and public awareness. However, the continual advancements in technology and a growing understanding of the potential applications of cord blood offer a promising future. As we address these barriers, we move closer to a future where a more comprehensive range of lifesaving treatments is accessible to all. This will allow us to fully harness the potential of cord blood and make the most of this invaluable resource.