Benefits of Cord Blood | Public Cord Blood Bank

The Advantages of Using Cord Blood for Transplants

By 1974, researchers had discovered that cord blood is rich in stem cells primarily of the hematopoietic system (our blood system). Years passed, however, before scientists were certain that these stem cells could be used for bone marrow transplants. Realization dawned that cord blood is a good source of hematopoietic stem cells, that is, cells that produce new blood cells when transplanted into a patient's bone marrow. More time passed as doctors and technicians developed methods to collect, process, and store cord blood in cord blood banks.

Finally, in 1988 the first cord blood transplant took place in Paris. On this occasion, doctors used cord blood taken from the patient's sister to save his life, he was affected by a certain genetic disease. Five years later in 1993, a leukemia patient received a cord blood transplant from an unrelated donor (a non-family member) for the first time.

Since then, cord blood transplants are constantly increasing worldwide together with ongoing development of improved storage and transplant techniques. Building on knowledge of the present, researchers and physicians are constantly developing applications and therapies of the future.

Cord blood banks have two major and significant advantages over bone marrow registries: availability and matching.

1. Availability - Cord blood is "shelf ready" in the public cord blood bank. Once a match between patient and cord blood unit is found, the unit is ready to save his life within hours or days. In contrast, the process of finding a suitable bone marrow donor and preparing his marrow for transplant can take from four to six months. The quick availability of cord blood significantly raises the odds of a transplant's success, as success is largely dependent on the patient's physical condition that can deteriorate with each passing day.  The immediate availability of cord blood directly affects the success of the transplant and the patient's recovery.

According to the United State's National Marrow Donor Program (NMDP), about a third of patients searching bone marrow registries for a suitable donor become unfit to undergo a transplant during the duration of the search.

The quick availability of cell blood is especially important for certain genetic diseases that are treatable by stem cell transplants. For example, babies can now receive transplants within a few weeks or months after birth before developing clinical symptoms of their genetic disease. Because transplants have an especially high success rate at this early state, building a large public cord blood registry will provide the best chance of survival for such infants.

2. Matching - Cord blood is collected from newborns whose immune systems are still not fully developed. This relatively 'naïve' blood can be used for successful transplants even when the cord blood does not perfectly match the patient's tissue type. It is acceptable to perform cord blood transplants when there is a match of only 4 or 5 out of 6 alleles (i.e 66-83%), whereas transplanting a donor's bone marrow or peripheral blood requires an exact match of 10 out of 10 alleles (only 100%).
 
This means that even a relatively small cord blood registry can meet the needs of many more patients, especially patients with rare tissue types.

In this context, it is worth noting that despite tissue type differences that exist between mother and fetus (the tissue type match between them is only 50%) and despite the continuous blood flow between the circulatory systems of the mother and fetus via the placenta – neither mother or embryo ever suffers rejection from the other. This is likely connected to what we said before, that cord blood transplants have a far smaller rejection rate even when donor and patient are not 100% matched. 

Other advantages of cord blood:

• There is no pain or risk to the donor (either the baby or the mother) when the blood is collected.
• It is easy to focus the cord blood collection among specific minority groups.
• Cord blood can be kept deep frozen at -1960C for many years.
• The cells are free from disease and defects that become more common as a donor ages.
• There is no danger of a matching donor refusing to donate later in life, or changing his mind during the transplant process
• There is less GVHD, 'graft versus host disease' that occurs when transplanted cells attack the cells of the recipient's (the patient) body. This phenomenon is a major cause of death and transplant failure in bone marrow transplants and plays a major role in the recipient's quality of life for many years after the transplant. This disease occurs far less severely after cord blood transplants and almost never occurs in its acute form.

However, at the moment cord blood still has disadvantages to bone marrow and peripheral blood transplants:

1. Fewer cells. Adult donors provide ten to a hundred times more stem cells than a cord blood donation does, because only a limited amount of blood remains in the umbilical cord after birth. Although doctors have developed ways of utilizing this smaller amount of cells for adults, until recently, most cord blood transplants were done on children or lightweight adults. Only in recent years have doctors developed methods of transplanting two cord units simultaneous into adults patients weighing over 30 Kg.. A number of technologies are inching closer to an even better solution: growing and multiplying cord blood cells in the laboratory.

2. Longer engraftment time. After a bone marrow transplant, it takes a few weeks until the cord blood engrafts in the bone marrow and begins proper blood cell production. During this time, the patient must remain in isolation to protect his body from life threatening diseases and infections. Cord blood transplants take ten to fourteen days longer to engraft than bone marrow and peripheral blood transplants due to the relatively smaller cell count. Researchers believe that the development of technologies to multiply cord blood cells in the laboratory and transplanting two units of cord blood at a time will help overcome this problem. This will be in addition to other methods already employed to encourage and improve engraftment.
It is important to note that despite the slower engraftment of cord blood, the results of cord blood transplants and long-term survival of patients are identical to the results of peripheral blood or bone marrow transplants.

3. Expenses. The expense of storing cord blood units is much greater than that of collecting a blood sample from a potential bone marrow donor to test for proper matching. Indeed, these high costs are the main obstacle to the increase of public cord blood banks. On the other hand, the high utilization of cord blood reserves (now over 5%) compared to the utilization of bone marrow registries (0.2% - 0.1) indicates the economic viability of public investment in cord blood banks. Indeed, according to current economic analysis there would be a greater long-term economic advantage in investing in cord blood banks.

4. Availability of donor for a repeat donation. When a repeat transplant becomes necessary, one cannot return to the donor to get more cord blood cells. Nor is it mostly possible to infuse leukocytes from the original donor. 
 
International knowledge and experience indicate the great importance of building more cord blood banks and enlarging those that already exist. These banks would provide a solution to hundreds of thousands of patients each year, many of whom currently have no alternative therapy.
 
In 2005, U.S. federal government budget allocated tens of millions of dollars for a multi-year period to expand the national registry of public cord blood, and in particular, to increase the amount of cord blood collected from ethnic minorities. Israel also enacted a Cord Blood Law in 2007 that allocated government funding to preserve a thousand cord blood units from various population groups according to criteria determined by the Ministry of Health.

Regarding each specific patient, transplant staffs use professional judgment to decide which stem cells are best for transplantation depending on the patient's unique circumstance.