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What Are Bone Marrow and Cord Blood Transplants?

For years cord blood transplants have been used as an alternative to bone marrow transplants in patients requiring a stem cell transplant. Both bone marrow and cord blood stem cell transplants are designed to replace unhealthy cells with healthy ones.

They are usually used to treat people with blood cancers such as Leukaemia.

A bone marrow transplant involves the use of bone marrow from a donor into a recipient to cultivate new stem cells.

Bone marrow is a spongy tissue located inside the bones and is most commonly extracted from the breastbone, skull, hips, ribs or spine, as these contain stem cells that:

  • Produce white blood cells (leukocytes), which fight against infection;
  • Red blood cells (erythrocytes), which carry oxygen in order to eliminate waste from the organs and tissue, and;
  • Platelets, which are responsible for making the blood clot.

How Are Stem Cells Harvested From Bone Marrow?

Bone marrow stem cell transplant operation

Bone barrow is removed from the donor under a general anaesthetic. It is filtered, treated, and either transplanted immediately into the recipient, or tested, frozen, and stored for later use.

Nearly 90% of people donate their stem cells in a process called peripheral blood stem cell collection.

The process involves having a course of injections prior to collection to stimulate the bone marrow and increase the number of stem cells and white blood cells in the blood.

During collection, you will have a needle in each arm for up to five hours.

The other 10% donate through bone marrow, where they give cells from the bone marrow in their pelvis.

How Are Stem Cells Harvested From Cord Blood?

Cord blood is collected from a newborn’s umbilical cord after delivery, so that it may be tested, frozen, and subsequently stored in a cord blood bank for future use.

The collection procedure is 100% safe for the mother and baby as it’s collected after birth from the otherwise waste material of the umbilical cord.

When Is Cord Blood Preferred Over Bone Marrow?

Graft Versus Host Disease (GvHD)

Cord Blood Preferred

Graft versus host disease is a potentially serious complication for any organ transplant. In fact, it is estimated to be fatal in up to 40% of patients.

However, because cord blood is more primitive than bone marrow, there is a lower chance that these cells will attack the recipient’s body, resulting in a lower incidence of GvHD.

Rich Source of Stem Cells

Cord Blood Preferred

Stem cells are found in greater proportions in umbilical cord blood. In fact, some experts say it contains nearly 10 times the amount of stem cells found in bone marrow.


Cord Blood Preferred

Stem cell transplants are in high demand, with over 30,000 individuals in line for the procedure each year.

The problem is that waiting for a suitable donor can often inhibit an individual from having the procedure. In fact, for this very reason, 70% of these individuals cannot find a matching donor.

Unfortunately, for some individuals, such as those with more severe types of cancer, this lack of treatment can be fatal.

Cord blood banking, however, helps to alleviate this issue, as their storage facilities make cord blood readily available for those in need.

HLA Matching

Cord Blood Preferred

Human Leukocyte Antigen (HLA) is a marker your immune system uses to recognize foreign cells.

HLA tissue types are inherited, which is why it is recommended that a recipient’s bone marrow donor be a family member (ideally a brother or sister).

This is a problem because 70% of donors do not have a suitable donor in their family. However, because cord blood stem cells are considered to be “purer” (and therefore more adaptable), there is generally no need to find an HLA match.

Regenerative Source

Cord Blood Preferred

It is believed that stem cells found in cord blood have greater regenerative properties since they are younger than bone marrow.


Cord Blood Preferred

From a donor’s perspective, a cord blood transplant presents a much less invasive procedure, as the collection of cord blood stem cells happens directly after birth from the umbilical cord.

Bone marrow transplants, on the other hand, are invasive procedures, requiring general anaesthesia so that bone marrow can be removed from the rear of the pelvic bone through a series of injections.

Graft Rejection

Bone Marrow Preferred

Despite the numerous advantages of cord blood transplants, bone marrow transplants are still preferred in the case of graft rejection– or a case in which the recipient’s body attacks the donor’s stem cells.

According to a recent study, some 11% of cord blood transplants were rejected, while this was the case in only 2% of bone marrow transplants.

Bone Marrow Stem Cells

Bone marrow stem cells are obtained in a painful and invasive procedure. It involves surgery and general anaesthesia.

Patients who had organ transplants using bone marrow stem cells often have Graft vs Host Disease (GvHD).

A stem cell from bone marrow can differentiate into a limited amount of blood-forming cells

Bone marrow stem cell transplants require the donor perfect match with the recipient.

Units of bone marrow harvested must be used freshly i.e it has a shelf life of mere hours.

There is no risk of transplanting a genetic disease.

For bone marrow stem cell transplants, even when a donor match is found, the donor must be found and re-tested.

Bone marrow transplants require a quart or more of bone marrow, mixed with blood.

Cord Blood Stem Cells

Collecting cord blood is painless and its stem cells are easily acquired.

GvHD is a lot less frequent and even when it occurs, it’s generally easier to treat.

A stem cell from cord blood forms more blood cells than a stem cell from the bone marrow.

In cord blood stem cell transplants, the donor and recipient can be mismatched, making it a lot easier to find a donor.

Units of cord blood can be cryopreserved for well over two decades.

There is a tiny risk that rare and unrecognised genetic diseases, found in the blood or immune system of the baby, may be transplanted.

Once stored, cord blood is available until whenever it is needed.

In cord blood transplants, only a small volume is required

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