Cord blood collection happens after the umbilical cord has been cut and is extracted from the fetal end of the cord, diverting up to 75 +/- 23 mL from the neonate. It is usually done within ten minutes of giving birth. Additional stem cells may be collected from the placenta. After the health care provider draws the cord blood from the placental end of the umbilical cord, the placenta is couriered to the stem cell laboratory, where it is processed for additional stem cells. An adequate cord blood collection requires at least 75mL in order to ensure that there will be enough cells to be used for a transplantation. Before the cord blood is stored for later use, it undergoes viral testing, including tests for HIV and Hepatitis B and C, and tissue typing to determine Human Leukocyte Antigen type. It will also be examined for nucleated cell count, cell viability, blood group antigen ABO & Rh blood group system, molecule cluster (CD34), and bacterial and fungal growth.
After the collection, the cord blood unit is shipped to the lab and processed, and then cryopreserved. There are many ways to process a cord blood unit, and there are differing opinions on what the best way is. Some processing methods separate out the red blood cells and remove them, while others keep the red blood cells. However the unit is processed, a cryopreservant is added to the cord blood to allow the cells to survive the cryogenic process. After the unit is slowly cooled to −90 °C, it can then be added to a liquid nitrogen tank which will keep the cord blood unit frozen at −196 °C. The slow freezing process is important to keep the cells alive during the freezing process. There is no consensus yet on optimal procedures for these cord blood cells, although many cryopreservation strategies suggest using dimethyl sulfoxide (DMSO), slow or controlled rate cooling, and rapid thawing.
Cord blood stem cells (though usually from donors) are currently used in the treatment of several life-threatening conditions, mainly blood and immune system related genetic diseases, cancers, and blood disorders. The first clinically documented use of cord blood stem cells was in the successful treatment of a six-year-old boy afflicted by Fanconi anemia in 1988. Since then, cord blood has become increasingly recognized as a source of stem cells that can be used in stem cell therapy. Recent studies have shown that cord blood has unique advantages over traditional bone marrow transplantation, particularly in children, and can be life-saving in rare cases where a suitable bone-marrow donor cannot be found. Cord blood stem cells can also be used for siblings and other members of your family who have a matching tissue type. Siblings have a 25% chance of compatibility, and the cord blood may even be a match for parents (50%) and grandparents.
The primary drawback of cord banking is that it is only beneficial in very rare situations. The likelihood of a child having an illness that would benefit from properly matched banked cord blood is 1 in 2700, though some experts think it is even less useful than that.
Stem cells from cord blood can be used to treat some diseases. If your child is born with a genetic disorder, the cord blood likely contains the same code that caused the problem in the first place. It cannot be used to treat your child, or any other person. Cord blood cells from a healthy infant can be used to treat an ill child, as long as the two are a good match.
The amount of stem cells from a single birth is enough to treat a child or young adult. Full-grown adults typically need more stem cells than are available in cord blood, though it is possible to combine stem cells from more than one birth. Additionally, the efficacy and safety of storing cord blood long enough for a child to become an adult has not been proven.
You may consider cord blood banking for any number of reasons. If your family has a history of disease that can be treated with cord blood, you may consider this option in case your child or another family member develops the condition. Or you may choose to bank cord blood just in case your child becomes ill, even if you have no family history. You may also choose to donate cord blood to a public bank to help other families.
Cord blood has proven advantageous over other options like public cord blood banking and bone marrow transplantation. There are many reasons including all of the following:
Easy to collect
There is no pain or risk for the mother or baby in extracting the blood from the umbilical cord, and the collection process is easily performed at the same time as the cutting of the umbilical cord. Bone marrow collection, on the other hand, requires an invasive, surgical procedure and general anesthesia, which comes with its own inherent risks.
For stem cells to be successfully transplanted, they must be
a match for the receiver. Matched stem cells can be found in some public
databases, but the chance of finding a match is low and complications can arise
with unrelated blood transfusions. Genetically related stem cells from a
blood-related family member more often result in a successful transplant. If a
public match cannot be found, the patient must often rely on his own stem cells
or those from an immediate family member (if available).
Someone’s own stem cells are always a perfect match for him or herself. Siblings share a 25 percent chance of being a perfect match and a 50 percent chance of being a partial match. Altogether, this gives siblings a 75 percent chance of being a possible match. Since each parent provides markers used in matching, parents have a 100 percent chance of being a partial match. This means a child’s cord blood stem cells could one day be used to help his or her mother or father. In the end, it is up to the doctor to determine how close the match needs to be to perform a transplant.
Less risk of post-transplant complications
In addition to being better accepted entirely by the body,
cord blood stem cells have significantly reduced risk of post-transplant
graft-versus-host disease (GVHD). GVHD is when the transplanted cells attack
the body. It’s a major complication of stem cell transplants. Risk of GVHD
after a stem cell transplant depends on the relationship between the donor and
the receiver according to the National Institute of Health:
Part of this better acceptance by the body is because cord blood stem cells have rarely been contaminated with latent viruses. The same is not true for stem cells from other sources. For this reason, cord blood stem cells have been dubbed “privileged” because they haven’t been exposed to any diseases.