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The History and Science Behind Cord Blood Transplants

Just three to five ounces of stem-cell-rich cord blood can be harvested with each baby born, but that three to five ounces can do so, so much, experts say.

“Cord blood has immature blood cells, and you can use these harvested stem cells to, basically, implant into patients that have problems with their own blood; for example, because of leukemia or lymphoma or other types of diseases that affect their own blood supply,” Suhail Sharif M.D., a surgical oncologist on the medical staff at Texas Health Fort Worth, recently told local NPR-affiliate KERA.

And those stem cells harvested from cord blood are special because they can make new cells. Their value lies in their potential: they can make new cells, which is something most cells in the body cannot do.

“The transplantation of blood-forming stem cells is an accepted treatment to restore the body’s ability to make blood and immune cells,” the Leukemia and Lymphoma Society explains. “Blood-forming or ‘hematopoietic’ stem cells (HSCs) can develop into any of the three types of blood cells: red cells, white cells or platelets.”

And what makes this all the more remarkable is that prior to the 1980s, the placenta and umbilical cord were thrown away as medical waste.

“Since the early ‘80s or so, research has taken place, and we realized that the blood from the umbilical cord and placenta have stem cells,” Sharif says, adding that around 1988, the first successful stem cell transplant from cord blood was performed.

“If you think about the blood that is in the placenta and the cord, it’s in the range of three to five ounces. That’s about half a cup,” Sharif says. “That’s the reason why you have to gather it from a lot of patients.”

“Cord blood samples have been preserved for as long as 10 years and have still been successfully transplanted,” the LLS adds.

Cord blood is also less invasive to harvest than bone marrow and can be used quickly, whereas bone marrow transplants take months to from start to finish.

“Cord blood stem cells are stored in a blood bank that you can withdraw from to use on patients that need it,” Sharif explains. “But bone marrow, you actually have to go through a process of harvesting it.”

“It’s a very painful procedure for whoever is donating the bone marrow.”

“Cord blood stem cells have already been stored and are readily available,” he adds. “And if you have a match with the donor and the recipient, you can use them right away.”

While experts don’t agree on the benefits of banking cord blood for your own child, they do agree that if there is a sibling or even family need, cord blood can be beneficial. A family member or sibling with a blood disorder, leukemia or sickle cell anemia, or a history of it, for instance, would benefit.

“I don’t think you’ll get arguments from any doctor about the wisdom of banking if you have one of these diseases running in the family,” says Jeffrey Ecker, MD, a high-risk obstetrician at Massachusetts General Hospital.

The matching for cord blood depends on human leukocyte antigen (HLA) matching, the LLS explains. Outcomes are better when the donor blood and the recipient have a better degree of HLA matching, and a close match can improve outcomes considerably.

“However, even though a closely matched cord blood unit is preferred, clinical studies suggest that the match may not have to be as close as the match that is necessary for bone marrow or peripheral blood transplants,” the group explains.

“It is important to note that there is a 25 percent chance that any two siblings will be fully matched for their HLA tissue type,” the LLS continues. “A baby’s cord blood will automatically share 50 percent of its HLAs with each parent; however, it will occasionally be a better match for a parent if both parents, by chance, have some of the same HLAs.”

The story around one of the first sibling transplants of cord blood was recently told by Joanne Kurtzberg, M.D., who now is the president of the Cord Blood Association, but at the time was a pediatric hematology and oncology fellow at Duke University. In her “History of Cord Blood Banking and Transplantation,” Kurtzberg wrote of Matthew, who was diagnosed with Fanconi anemia and bone marrow failure.

“This genetic disease, which arises from a mutation in genes that encode the enzymes responsible for DNA repair, is associated with a host of serious medical and developmental problems,” Kurtzberg wrote. “The prognosis for Matthew’s condition was stark: most children with Fanconi anemia died of bone marrow failure or leukemia in the first decade of life, unless treated with a bone marrow transplant from a human leukocyte antigen (HLA)-matched donor.”

Matthew didn’t have that match, and time was running out when his mother became pregnant. After tests to see if Matthew’s new sibling would also have Fanconi anemia revealed she did not, the doctor who analyzed the sample put Matthew’s team in touch with a group pioneering the research into cord blood transplants—a team led by doctors Ted Boyse, Judy Bard, and Hal Broxmeyer of Memorial Sloan-Kettering Cancer Center.

“Although Matthew experienced an infusion reaction, there were no significant complications and 19 days later, he [was] engrafted with his baby sister’s cord blood cells, effectively curing Matthew of Fanconi anemia,” Kurtzberg writes. “Now in his early thirties, he is leading a healthy, normal life.

“In my opinion, cord blood is 18 years young and still has a long developmental pathway ahead,” she concludes. “It is remarkable that a routinely discarded substance can save lives.”

Is cord blood banking right for your family? Experts recommend having that conversation with your obstetrician at around the halfway mark of pregnancy. Need help finding the right OB/GYN for you? Use our “Find-a-Physician” tool to make the search easier.

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