7 QUESTIONS AND ANSWERS ABOUT CORD BLOOD
  
  NeatBuzz has the hottest, most social content on the web. you will love all kinds of things you'd want to pass along to your friends.  
     
 

  « Previous Article

Next Article »  

7 QUESTIONS AND ANSWERS ABOUT CORD BLOOD



Published On: September 8, 2014, by Neat Buzz, Ruth Campbell, Virginia
Tag: Blood, Cordblood , Rating: 4.5

GENERAL CATEGORY
 
         
 

Share on Facebook   Tweet   Share on StumbleUpon

7 QUESTIONS AND ANSWERS ABOUT CORD BLOOD  | NEATBUZZ.COM

cord blood

noun: cord blood; plural noun: cord bloods

- blood from the human umbilical cord, a source of stem cells.



1

 

WHAT IS CORD BLOOD?

 

After a baby is born and the umbilical cord is cut, some blood remains in the blood vessels of the placenta and the portion of the umbilical cord that remains attached to it. After birth, the baby no longer needs this extra blood. This blood is called placental blood or umbilical cord blood: "cord blood" for short.

Cord blood contains all the normal elements of blood - red blood cells, white blood cells, platelets and plasma. But it is also rich in hematopoietic (blood-forming) stem cells, similar to those found in bone marrow. This is why cord blood can be used for transplantation as an alternative to bone marrow.

Cord blood is being used increasingly on an experimental basis as a source of stem cells, as an alternative to bone marrow. Most cord blood transplants have been performed in patients with blood and immune system diseases. Cord Blood transplants have also been performed for patients with genetic or metabolic diseases. More than 80 different diseases have been treated to date with unrelated cord blood transplants.

Scientists are investigating the possibility that stem cells in cord blood may be able to replace cells of other tissues such as nerve or heart cells. Whether cord blood can be used to treat other kinds of diseases will be learned from this research.

7 QUESTIONS AND ANSWERS ABOUT CORD BLOOD
  

2

 

WHY DO WE NEED TO HAVE CORD BLOOD DONATED TO PUBLIC BLOOD BANKS?

 

1. Cord blood donated to a public bank provides another source of hope for patients who have no matching donor in their own family, no unrelated donor in bone marrow donor registries that is a suitable match or no time to find a donor. As with bone marrow, cord blood stem cells may be capable of generating all the cellular elements in the blood and immune system.

2. Donated bone marrow or peripheral blood containing mobilized stem cells have been the traditional sources of hematopoietic stem cells for transplantation. Their donors should be closely matched to the recipient; that is, matched at least for the HLA-A, -B, -C and -DRB1 alleles. Since there are usually two alleles for each, in a perfect match, the donor will have the same eight alleles as the patient, an 8/8 match. A perfect match is most likely to occur among family members. Among brothers or sisters of a patient, for example, each has a 25% chance of being a perfect match. Because the average number of children in U.S. families is slightly more than two, about 3 out of 10 patients will find such a match among their own siblings. Other blood relatives also may be well-matched but the chance is much lower.

When no relative is available, some other source of stem cells must be found. Bone marrow from unrelated donors has helped solve this problem for thousands of patients. Marrow donor registries around the world have recruited fourteen million volunteers willing to donate their bone marrow to a perfect stranger. The largest registry in the United States is the National Marrow Donor Program (NMDP) currently, the “Be the Match” Registry, which lists some 5.5 million volunteers.

3. Many patients who need a bone marrow transplant, however, cannot find a suitable donor - no relative that matches and no match among volunteer bone marrow donors. According to a report from the U.S. Government Accounting Office (GAO) released in October 2002, 10,000-15,000 people in the U.S. each year have a disease that could be treated with a transplant, but have no HLA-matched related donor. About one-third of these patients tried to find unrelated marrow donors through the NMDP but only 25% of them (9% of the total who might benefit) actually could get a transplant. The odds were even worse for African-American and other ethnic minority groups. This was one reason for the broad legislative support behind the Stem Cell Therapeutic and Research Act of 2005.

4. A cord blood transplant may not have to be a perfect match to the patient. Adult bone marrow contains immune cells (so-called T-lymphocytes or T-cells) that are “fully mature”. When transplanted, these T-cells may attack the patient`s cells as “foreign”, causing a condition called graft vs. host disease (GvHD), which can be severe and even lethal. T-cells in cord blood do not appear to be as "immunologically mature" as those in bone marrow. As a result, cord blood transplants may be less likely than bone marrow to cause GvHD and, when it does occur, it appears to be less severe. Because cord blood transplants may cause less GvHD, it appears that the match to the patient does not need to be perfect. In fact, most cord blood transplants so far have been 5/6 or 4/6 matches for HLA-A, -B and -DRB1 antigens. This means that patients who cannot find a perfectly matched bone marrow donor may have a chance to find a suitable cord blood transplant. Patients with rare HLA types, African-Americans and members of other minority groups, therefore, could benefit especially from this stem cell resource.

7 QUESTIONS AND ANSWERS ABOUT CORD BLOOD
  

3

 

WHAT ARE THE ADVANTAGES OF CORD BLOOD?

 

Cord blood offers a number of advantages to donors and transplant recipients. It is easy to collect, often more likely to provide a suitable match and is stored frozen, ready to use.

1. Cord blood collection is easy and poses no medical risk to the mother or newborn baby.
Cord blood collection is a safe, simple procedure. The New York Blood Center`s National Cord Blood Program staff collects cord blood from the delivered placenta, in a way that does not interfere with the care of the mother or newborn baby. Collection, therefore, poses no risk to mother or baby.

2. Cord blood is collected in advance, tested and stored frozen, ready to use.
Cord blood is donated in advance for anyone who might need it in the future. All routine testing is completed and the unit is stored frozen, ready to use. If a match is found, it can be reserved immediately. Confirmatory HLA typing and any special testing required is usually completed within 5 days. Unlike bone marrow, there is no need to take time to locate a possible volunteer and then determine whether he or she is still willing and able to donate.

3. Cord blood transplants do not require a perfect match.
Studies have shown that cord blood transplants can be performed in cases that the donor and the recipient are partially matched. In contrast, bone marrow grafts require 8/8 matching in most cases.

Because partially matched cord blood transplants can be performed, cord blood increases the patient’s chance to find a suitable donor. With cord blood, a relatively small donor pool can effectively support most patients` needs. We have estimated, for example, that a national inventory of 150,000 cord blood units would provide acceptable matches for at least 80-90% of United States patients.

4. Cord blood transplants are associated with lower incidence of GvHD.
The immune cells in cord blood seem to be less likely than those in bone marrow from unrelated donors to attack the patient`s own tissues (graft vs. host disease).

5. Cord Blood Transplants are associated with lower risk of viral infections.
Cord blood is also less likely to transmit certain common viruses, like Epstein-Barr virus (EBV) and cytomegalovirus (CMV), potentially lethal infections for transplant recipients. CMV is carried as a latent virus by about half of the adult U.S. population, whereas less than 1 percent of infants are born with CMV.

7 QUESTIONS AND ANSWERS ABOUT CORD BLOOD
  

4

 

WHY IS CORD BLOOD IMPORTANT FOR ETHNIC MINORITIES?

 

There are differences in the frequency of certain HLA types among ethnic groups. Therefore, patients are more likely to find a good match among donors from their own ethnic group. African-American patients who need bone marrow transplantation have an especially hard time finding an unrelated bone marrow donor. There are three reasons for this difficulty. The first is simply numerical. African-Americans make up only 12% of the U.S. population and, thus, fewer potential donors are available. The second reason is that there is much greater variation in HLA-types among people with African ancestry than in any other group. And third, some people who have both African and European or other ancestry may have novel combinations of HLA types that are not found in either parental population.

Epidemiological estimates indicate that at least three times as many African-American volunteer bone marrow donors than Caucasian donors would be needed for African-American patients to have a chance that equals that of Caucasian patients to find a match in the same bone marrow donor registries. As a result, African-American patients are much less likely to find a matched, unrelated bone marrow donor. With cord blood, however, a partial match is acceptable and most African-American patients can find a suitable cord blood unit. Large public cord blood bank inventories, therefore, can help make up for the difficulty in finding suitable bone marrow donors for minority patients.

African-American patients, like all other patient groups, may need transplants for leukemia, lymphoma, and inherited diseases such as severe combined immune deficiency (SCID or "boy-in-the-bubble" syndrome). In addition, African-Americans are more likely than others to suffer from sickle cell disease, a sometimes devastating and crippling disease that eventually could be lethal for most patients. At present, the only cure is a hematopoietic stem cell transplant. Early results show that patients with sickle cell disease can benefit from cord blood transplants, either from related, or from unrelated donors. Sickle cell patients do better, however, if transplanted early in life. They have a much better chance to survive after the transplant and they are spared the devastating life-time effects of sickle cell disease.

Note: Unrelated hematopoietic stem cell transplantation is not suitable for all Sickle Cell patients and may be used for certain patients with severe Sickle Cell Disease.

The New York Blood Center`s National Cord Blood Program has provided cord blood transplants for over 3,500 patients to date (more than 2,300 in the U.S.) from a growing inventory that currently numbers over 50,000 cord blood units. Of U.S. patients transplanted, 54% have been non-caucasian; 16% of those patients have been African-Americans and 20 of those patients had sickle cell disease.

Patients from other ethnic minority groups also have more difficulty finding a matching unrelated bone marrow donor. Again the problem is numerical. Minority groups simply have smaller numbers from which to draw potential donors. Many Hispanic patients also have ancestors from more than one ethnic group and people from different regions of Asia also tend to differ from Caucasians in their HLA types. For this reason, cord blood banks established in other parts of the world could benefit many U.S. citizens. A Japanese-American, with four Japanese grandparents for example, would have a much better chance of finding a suitable cord blood unit through the Japanese National Cord Blood Program than from a U.S. Cord Blood Bank.

7 QUESTIONS AND ANSWERS ABOUT CORD BLOOD
  

5

 

ARE THERE ANY UNFAVORABLE ASPECTS OF CORD BLOOD TRANSPLANTS?

 

The main disadvantage of cord blood is that the volume collected is fixed and relatively small. Therefore, the number of stem cells available for transplantation is low compared to the number of cells that can be collected in customizable bone marrow or peripheral blood stem cell harvests. The average total nucleated cell dose (number of nucleated cells per kilogram of the patient`s weight) in a cord blood graft, for example, is less than about 1/10th that of the average bone marrow graft. As a consequence, engraftment (the return of nucleated blood cells, red blood cells and platelets) to the patient’s blood is slower with cord blood than with bone marrow transplants. Cord blood transplant patients, therefore, may be more vulnerable to infection in the first two to three months after their transplant. This problem is greatest for adolescents and adults because they require a relatively large number of cells. [See Ongoing Research for encouraging news about stem cell expansion].

A cord blood transplant also may give the patient one of the rare genetic diseases of the blood or immune system. Families who donate cord blood are asked about their ethnic background and family history of genetic diseases. Cord blood is tested for common genetic diseases such as sickle cell anemia. And we obtain information about diseases that may be found in the infant before he or she is sent home after birth. However, some genetic diseases may not be apparent in the child for months or years and will not be found or even suspected by current screening methods. At present, it is also not possible to test for all of these rare diseases. Thus, there is a chance that a cord blood transplant may transmit to a patient a rare serious genetic disease that was not recognized beforehand.

Another disadvantage of cord blood is that the donor cells come from a newborn infant that will not be available for an additional donation of cells or bone marrow. In bone marrow transplants, on the other hand, the donor may be asked to make a donation of white blood cells (T-lymphocytes or T-cells) to help fight a recurrence of leukemia or development of lymphoma. Or a second marrow donation might be needed if the first one fails to engraft. T-cell donations and second transplants from the same donor are not available with cord blood. Another cord blood unit from a different donor would have to be given if the first one fails.

7 QUESTIONS AND ANSWERS ABOUT CORD BLOOD
  

6

 

WHAT IS CORD BLOOD USED FOR?

 

Cord blood has been used in the treatment of more than 80 different diseases so far. The most common disease category has been leukemia. The next largest group is inherited diseases (of red blood cells, the immune system and certain metabolic abnormalities.) Patients with lymphoma, myelodysplasia and severe aplastic anemia have also been successfully transplanted with cord blood.

7 QUESTIONS AND ANSWERS ABOUT CORD BLOOD
  

7

 

HOW LONG DO FROZEN CORD BLOOD CELLS REMAIN VIABLE?

 

It is not known how long cord blood can be stored in liquid nitrogen and its cells remain viable. NCBP`s earliest units were stored in 1993. In checking the viability of cells in cord blood units that will not be used for transplantation, we have not detected any deterioration in the quality of the cells in cord blood units stored for up to 16 years. Units stored for up to 13 years have been used in transplants and the outcomes have been similar to those of newly collected units. Thus, we are not aware of any reason to expect any significant deterioration in the quality of stored cord blood units.

7 QUESTIONS AND ANSWERS ABOUT CORD BLOOD
  


Share on Facebook   Tweet   Share on StumbleUpon


Comments Powered by Disqus