January 15, 2015 | by Nicole White
What most people call a "bone marrow transplant" is not actually a transplant of bone marrow; it is instead the transplantation of what's known as hematopoietic stem cells. Such cells are often taken from bone marrow, but not always.
Hematopoietic stem cells are simply immature cells that can develop into any type of blood cells, including white blood cells, red blood cells and platelets. They're used to treat blood cancers and other hematologic disorders, and they can come from bone marrow, peripheral blood (blood that circulates through the arteries and veins) or even umbilical cord blood banked at the time of a baby’s birth.
Transplantation follows a fairly similar process: First, a donor (or in some cases, the patient himself) provides stem cells that match the patient's blood cells in key ways. Then the patient is treated with chemotherapy and radiation to prepare him for the transplant, and the new cells are infused.
Having access to all options for stem cell transplantation is important for patients with a blood cancer or other hematologic malignancy, said Chatchada Karanes, M.D., director of the Cord Blood Transplant Program in City of Hope’s Hematologic Malignancies and Stem Cell Transplantation Institute, because many factors must be weighed when choosing the best transplantation option for a patient.
Some of the factors are pure science: What kind of cancer does the patient have, and what is the patient’s human leukocyte antigen – or HLA – the protein marker used to match a patient with a donor? Some of the factors are a matter of logistics: Does the patient have a family member who is an HLA match? Is there an unrelated donor who is available? How severe is the patient’s disease – that is, how much time can be spent searching for a match?
In cases for which no matched related or unrelated donor is available, other sources for these precious stem cells must be considered. One method features a haploidentical stem cell transplantation, using a donor who is a half-match, but not a perfect match, for the patient.
“The stem cell transplant is evolving over time,” Karanes said. “We wouldn’t have been able to offer these options in the past. It’s especially difficult for ethnic minorities to find donors in time. So having these other stem cell sources is important.”
Karanes said cord blood transplants are constantly improving. In fact, City of Hope is currently working on two clinical trials related to cord blood transplant. One study uses matching stem cells from multiple umbilical cords, and expands the stem cells in a lab so patients receive more healthy stem cells during their transplant.
Another clinical trial seeks to improve the homing ability of the cells to the bone marrow. The cord is incubated with prostaglandins, compounds that seem to activate a receptor in the cells that helps them attach to the bone marrow.
These additional options now allow patients who years ago would not have had the possibility of a transplant to receive the best therapy currently available for blood cancers.
“There’s a lot of data in the past 20 years that stem cell transplant after high-dose chemotherapy and radiation can produce a long-term remission and possible cure in patients who are diagnosed early,” Karanes said. “Now these transplants are available to more patients than ever.”
Learn more about becoming a patient or getting a second opinion at City of Hope by visiting our website or by calling 800-826-HOPE (4673). City of Hope staff will explain what's required for a consult at City of Hope and help you determine, before you come in, whether or not your insurance will pay for the appointment.