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Dr Ng Soo Chin
Consultant Haematologist
(This article appeared in Berita MMA and is reproduced here with the permission of the author)
Preamble
Expecting parents are faced with a lot of important decisions before their baby is born. These include the basics, such as what to name the baby, which hospital and doctors to go to, breastfeeding vs. formula feeding, etc. And more and more, they have to consider the issue of whether or not to bank or store their baby’s umbilical cord blood (UCB) and in Malaysia, which company to bank with since there are now 3 competing companies!
What does the umbilical cord blood contain?
The presence of haematopoietic stem cells is the cell of interest. Compared to stem cells form bone marrow, the UCB stem cells are more primitive and more’ naïve’ and as a result allogeneic transplant can be done with only a partial HLA matched. There is likely presence of other cells of importance such as the mesenchymal and neural precursor cells which may be grown into other lineages such as, cartilage, fat, hepatic or cardiac cell under suitable environment.
What are the differences between public or community cord blood banking and private cord blood banking?
The public cord bank or community cord blood bank receives cord blood from voluntary donors and they are typed and stored for anyone who needs to use it. The bank is usually affiliated to a university and is run as a non –profit organization. The center that requests for the cord blood for use for specific patients will need to pay a fixed sum to the public cord bank to defray the expenses incur in collection, typing and storage of the cord blood.
The private cord blood banks cater for the individual family who chooses to store the baby’s UCB at time of birth. The parents concerned will need to pay for the collection and storage fees. They are run as a business concern and not infrequently, there were criticisms of hard- selling their services. There are currently 3 companies that provide such services in Malaysia and not surprisingly there is a tough fight for the clients who can afford such services.
What is the long-term viability of frozen cord blood?
So far, recovery of viable stem cells from cord blood is over 90% at 15 years^1. In theory, it should be possible to store cells for millenia at -196 C, the temperature of liquid nitrogen. Below -130 C, no liquid water exists in cells, which prevents biochemical reactions between molecules dissolved in water. At -196 C there is not enough thermal energy in the cell to drive any biochemical reaction. The only degradation that can occur at this temperature is reactions caused by cosmic background radiation. It can be calculated that, at normal terrestrial conditions, it would take about 2000 years before such reactions caused a significant amount of damage^2.
What are the potential benefits of collecting and storing umbilical cord blood?
If one reads through a brochure on private cord banking, UCB storage is branded as a form of medical insurance and it can be used for treatment of both malignant and benign blood disorders. Because umbilical cord blood contains a rich source of hematopoietic stem cells and progenitor cells, it has been effective as an alternative allogeneic donor source in a variety of pediatric genetic, hematologic, immunologic, and oncologic disorders. The potential uses in regenerative medicine and degenerative disorders such as Parkinson’s diseases are generally highlighted.
What the cord bank operators fail to tell you?
The amount of stem cells harvested in the UCB will fall short of the minimum number required for stem cell or bone marrow transplant if the kid grows up to more than 100 pounds! On average, a cord blood sample contains 8.6 million nucleated cells per milliliter, and a successful transplant requires harvesting 1 milliliter of cord blood per pound of patient weight^3 .There are intense research going on to expand the cells in vivo and there are anecdotal reports of such success but it is not going to be easy and certainly will be an expensive undertaking. Certain childhood malignancy such as the common acute lymphoblastic leukemia (ALL) is unlikely to benefit much from autologous UCB transplantation.
What is the chance of using the stored cord blood?
The probability that the average child will require a transplant of her own stem cells before age 20 has been estimated as 4 in 10,000 (.04%)^4. Current estimates place the chances of a child needing to use his or her own cord blood sample at somewhere between 1 in 1,000 and 1 in 200,000^4
However, over the course of a lifetime up to age 70, the probability that a person will require a transplant of her own stem cells is 1 in 450 (0.23%), and the likelihood of requiring any transplant, from yourself or a sibling, is 1 in 220 (0.46%)^5. In other words it is not a common happening especially in the childhood when stem cell transplant is needed
What are the recommendations of the Professional bodies?
The American Association of Paediatrics in the latest 2007 policy statement^6 stated that private UCB storage as ‘biological insurance’ should be discouraged. There is not enough evidence to support the routine harvesting and storage of umbilical cord. The AAP panel express concern that “families may be vulnerable to emotional marketing (from private blood banks) at the time of birth of a child and may look to their physicians for advice.” They point out that the vast majority of children will never require the use of stored cord blood. The AAP experts conclude that because the potential uses of cord blood remain extremely “limited,” cord blood banking should only be considered “if there is a family member with a current or potential need to undergo a stem cell transplantation.” On the other hand, they encourage parents to donate cord blood “at no cost” to national stem cell banks, in much the same that organs are donated to help strangers in need. Parents should give informed consent before donating cord blood, and contact between the donor family and blood bank should be maintained in case “a genetic disease or (leukemia) develops” within the donor family.
The Royal College of Obstetrics and Gynaecology of United Kingdom ^7 in 2006 proclaimed that”…there is insufficient evidence to recommend directed commercial UCB collection and storage in low risk families.
The European Group in Ethics in Science and New Technologies in 2004 wrote to the European Commission that the legitimacy of commercial cord blood bank for autologous or own use should be questioned as they sell a service, which has presently, no real use regarding therapeutic options. Thus they provide more than they can deliver. The activities of such banks raised serious ethnical criticisms. The same group recommended any kind of advertisement by commercial cord blood bank in the media, including the internet must be adequately controlled by public authorities. The support for public cord bank should be increased
What are the latest results of UCB transplants?
The use of umbilical cord blood to treat a wide variety of diseases is a relatively new and growing technology. More than 5500 unrelated-donor cord blood stem cell transplantations have been performed for malignancies, bone marrow failure, hemoglobinopathies, immunodeficiencies, and inborn errors of metabolism. Cord blood may be superior to bone marrow stem cell transplantation because of greater availability, a reduced risk for graft-vs-host disease, and less risk for blood-borne illness. However, autologous cord blood has less potential to treat diseases such as leukemia because the genetic traits for cancer exist within the blood sample destined for transplantations.
Historically UCB transplants have significantly high mortality due largely due to slow engraftment of stem cells. New innovate approach using double cord blood collection seemed to improve the transplant results. If double cord turns out to be the transplant format of choice, it would mean the storage of own UCB is an inadequate exercise as one still has to source for another cord blood collection.
What if I have not stored my child’s cord blood and he/she is struck with the dreaded illness mentioned, is she/he doomed?
Take a deep breath and calm down. You could search from the public cord blood bank or from the bone marrow registry for potential donors if no sibling matched donor is forth-coming. Some types of cancer with genetic basis e.g. Acute lymphoblastic leukaemia (ALL) may be best treated with stem cells form allogeneic source or different persons.
How do I feel (does it matter?) about the whole thing?
In the ideal world all children should have their UCB stored but for the expenses and logistics involved. I have no problems with people storing cord blood for own use later. Neither have I had any qualms about private companies collecting storing cord blood stem cells. My concern is that as consumers the parents are not being presented with the whole truth and this is not acceptable from viewpoint of good clinical practice. I am also concerned about the ‘entrapment syndrome’—the private cord blood Co can present various reasons to up their fees in the future and I don’t think the consumers have very little to fight back. What if the company folds? Despite being claimed as a form of medical insurance, I agreed with Dr Mitchell Cairo (Pediatric oncologist and stem cell researcher) that insurance should have a definable pay-offs and not on theoretical considerations. Perhaps, parents should instead invest on educational or health insurance for the baby rather than on something nebulous as private cord blood banking!
Disclaimer: The author has no personal interest in any of the private cord blood companies.
REFERENCES
1. Kobylka, P., et al. 1998, Transplantation, 65(9):1275-1278.
2. Mazur P. 1988, Ann NY Acad Sci. 541:514-31. “Stopping biological time. The freezing of living cells”
3. W Reed, et al, Blood 2003; 101(1):351
4. FL Johnson, 1997; J Ped Hem Onc 19(3): 183-186
5. : Pasquini, MC, Logan, BR, Verter, F, Horowitz, MM, & Nietfeld, JJ 2005 ASH meeting poster#5260
6. Pediatrics. 2007;119:165-170
7. Royal college of Obstetrics and Gynecology: Scientific advisory committee opinion paper 2:June 2006
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