Stem Cell Innovations
Doctors and researchers at Seattle Cancer Care Alliance (SCCA) and Fred Hutchinson Cancer Research Center, an SCCA parent organization, continually devise and implement improvements in stem cell transplantation for children and adults. Here are some of the latest developments benefiting our pediatric patients who have cancer or a non-malignant immune system disorder or hematologic (blood) diseases.
- Source of Hope: How Cord Blood Transplants Help More Kids Many of our pediatric patients who cannot find a donor any other way have benefited from stem cells derived from umbilical cord blood.
- Curing Non-malignant Diseases Stem cell transplants may help treat immune deficiencies, autoimmune diseases, like juvenile rheumatoid arthritis, and blood diseases, like sickle cell anemia. Read more information on the development of stem cell transplants for non-malignant diseases.
- Infants May Benefit from Transplantation “Our results here are the best in the world,” says Dr. Jean Sanders, about stem cell transplants for infants with acute lymphoblastic leukemia. Sanders directs our Pediatric Clinical Hematopoietic Cell Transplantation Service.
How Cord Blood Transplants Help More Kids
By 2006, about 50 children had received cord blood transplants at Seattle Cancer Care Alliance. As this source of stem cells expands, the transplant donor pool expands as well, making stem cell transplants available to a greater number of patients. This can be especially important for ethnic minorities and those who have mixed ethnicity or unusual tissue types — in all these cases, it’s more difficult to find a suitably matched donor.
Where Cord Blood Comes From
Stem cells for a hematopoietic cell transplant can come from three sources: bone marrow, peripheral blood (the blood that circulates around your body), or the blood that remains in the umbilical cord when a mother and newborn are separated. Most cord blood is discarded. But some is collected in banks so that people who need stem cell transplants can use it.
The stem cells from cord blood are more versatile than those from bone marrow or peripheral blood, simply because the infant donor’s immune system is immature. The stem cells are relatively "uneducated" compared to cells from an older child or an adult. So there’s less likelihood of an adverse interaction between the transplanted cells and the recipient’s cells. This means that in order to be useful, stem cells from cord blood do not have to match the recipient’s tissue as closely as bone marrow or peripheral blood stem cells do.
Other than the source of the stem cells, a cord blood transplant is very similar to a bone marrow or peripheral blood stem cell transplant. The main difference is that it sometimes takes longer for the transplanted cells to engraft — to establish themselves in the recipient’s body and begin producing blood cells. Longer time to engraftment means more time without adequate numbers of the white blood cells that guard against infection.
Smaller is Better — For Now
The benefits of cord blood transplants especially apply to children. Cord blood yields fewer stem cells than other sources. Children, because of their smaller physical size, don’t need as many donor cells as adults do in order for a transplant to succeed. Soon the tide may turn for adults, thanks to a breakthrough by Dr. Colleen Delaney at SCCA. She is developing a promising method to increase the number of stem cells available from a single cord blood sample so the sample is even more effective in children and is useful in larger recipients, too. Delaney has also worked successfully on giving recipients two units of cord blood, each from a different donor, to increase the number of stem cells they receive.
Read more about Delaney’s research at Fred Hutchinson Cancer Research Center into cord blood transplantation.
Read more about our work in alternative donor options.
Curing Non-malignant Diseases
You may know about bone marrow and stem cell transplants because they are used to treat some forms of cancer, but these remarkable procedures may work against non-malignant immunologic or hematologic diseases, too. At SCCA, we are using and studying hematopoietic cell transplants for conditions such as inherited immune deficiencies, autoimmune diseases, like juvenile rheumatoid arthritis, and nonmalignant blood diseases, like sickle cell anemia.
Replacing a System That Doesn’t Work
Children born with severely deficient immunes systems are at increased risk for infections, some serious. Without a working immune system, these children cannot guard against invaders, like bacteria and viruses. At SCCA and the Hutchinson Center, our doctors and researchers are working together, along with immunologists from UW Medicine, to explore the use of hematopoietic cell transplants to provide the foundation of a functional immune system for children who need it.
“These are rare diseases in childhood and they are quite diverse in their presentation,” says Sanders. “But they usually present in the first year of life with an increase in serious infections.” Because the deficiency presents so early, many of these children do not yet have siblings who might be a match for a transplant. “They are often only-children, so we need to look for alternative donors for that population of recipients.”
Dr. Lauri Burroughs spearheads our work to treat immunodeficiencies with transplantation. Her research studies include innovative work using haploidentical donors, unrelated donors, and cord blood. We have been performing an increasing number of transplants for children with immune deficiencies and are excited to expand this work and make transplants available to more kids who may benefit.
Turning Off the Body’s Attack on Itself
In most children, doctors can manage juvenile rheumatoid arthritis (JRA) quite well with standard therapies, such as medicines to control pain and inflammation, and exercises to keep joints flexible and healthy. However, each pediatric hospital typically sees a few patients whose JRA causes severe disability and seriously impacts their quality of life. For these children, a hematopoietic cell transplant may be an option.
“The theory is that by doing an autologous transplant — using their own cells to repopulate their marrow — the autoimmune part of that disease will be turned off,” explains Sanders.
Dr. Ann Woolfrey leads our efforts to research and develop this exciting treatment option. “It was actually her idea to transplant those patients,” says Sanders. “We want to get the word out to the world that we do have protocols to transplant kids who have very severe cases of rheumatoid arthritis.”
Woolfrey also works on using transplants for other non-malignant diseases, including immunodeficiencies; hematologic diseases, such as sickle cell anemia, aplastic anemia, Fanconi anemia, and thalassemia; and metabolic disorders. Nonmyeloablative transplants (also called “mini transplants”) have proven helpful for some children with these conditions.
As the director of unrelated donor programs for pediatric transplants, Woolfrey also collaborates with other doctors and researchers at SCCA and the Hutchinson Center to develop alternative transplant options for children who do not have either a relative or an unrelated donor whose tissue closely matches their own. Cord blood transplants and haploidentical transplants are options for some of these children. "The focus of my work is trying to improve the outcome of patients with nonmalignant diseases and to improve the outcome of patients who do not have a matched donor,” says Woolfrey.
Infants May Benefit from Transplantation
Even infants may benefit from a hematopoietic cell transplant in some cases, and doctors at SCCA and the Hutchinson Center lead the way in performing transplants on these especially young patients.
“Our results here are the best in the world,” says Sanders — which puts us ahead of the curve when it comes to confidence about working with infants.
Improving the Odds for Survival
We have had great success performing transplants for infants with acute lymphoblastic leukemia (ALL) diagnosed before the age of one year. In these children, use of transplantation is controversial. The Children’s Oncology Group (COG), a national consortium of pediatric cancer care centers, recommends against transplantation for these children, says Sanders. However, their overall rate of disease-free survival is only 20 percent with conventional chemotherapy, she explains — while it’s 76 percent among those who receive a transplant through SCCA and the Hutchinson Center.
Overall, transplant results from COG institutions have not been as high as ours in infants with ALL, says Sanders, which most likely accounts for COG’s hesitation about recommending transplants in this group of children.
“I would like to perform transplants in more infants like this,” says Sanders, “because I think it is clearly in the infants’ best interest.”
Attention to Detail and Constant Research Pay Off
The approach to transplants at SCCA makes an important difference in our success rate, says Sanders. “I think it’s because of our attention to detail through our patients transplant time and after. We keep them here 100 days,” she says, “and we have graft-versus-host disease programs that are second to none.”
In 2005, 95 percent of children who had a hematopoietic cell transplant at SCCA for any reason survived at least 100 days. Doctors commonly use the 100-day survival rate as one measure of transplant success. A 95 percent survival rate means our rate of death from transplant-related complications is very low, explains Sanders.
Our rigorous and continuous research into transplant techniques and post-transplant care account for much of the success, says Sanders. “We are constantly improving our approach to various problems through clinical research,” she says. “Our research programs are ongoing, and that’s different from most transplant centers in the United States.”
Infants have all the same donor options as older children and adults have, including siblings and other family members, unrelated donors and cord blood. If you want to know more about whether a transplant may be appropriate for your infant, contact Seattle Cancer Care Alliance at (206) 987-2106.
For the definitions of terms listed in this section, please see Definitions.