Not every child who needs a stem cell transplant can find a donor—either a relative or someone unrelated—whose tissue matches their tissue closely enough to expect a good chance of success. But with recent advances in transplant protocols, the percentage of children who are at a disadvantage is shrinking. Researchers at Fred Hutchinson Cancer Research Center, a founding organization of Seattle Cancer Care Alliance (SCCA), are working hard to improve “alternative donor transplants”—transplants using stem cells from cord blood or from haploidentical donors.
Both methods can succeed even when the recipient’s and donor’s tissue types do not closely match. This is especially important for patients who belong to ethnic minorities or have mixed ethnicity, because they often have trouble finding a donor whose tissue type closely matches their own.
Cord Blood and Haploidentical Transplants
If the search for an unrelated donor produces no options, doctors may turn to a cord blood transplant or a haploidentical transplant. These options are an important area of focus for doctors at the Hutchinson Center. Several protocols have been developed for using these types of transplants for treating both malignant and nonmalignant diseases.
Cord blood transplants use stem cells from the blood that remains in the umbilical cord when a mother and newborn are separated. Because the infant’s immune system is immature, a cord blood transplant can succeed even if there’s a greater disparity between the infant’s tissue and the recipient’s tissue than would be allowed in a bone marrow or peripheral blood stem cell transplant. For more information, see Improving Cord Blood Transplants.
A haploidentical transplant uses cells from a relative whose tissue is not considered a suitable match according to usual tissue-typing standards. Haploidentical donors have one haplotype in common with the recipient, so they match on at least five out of 10 points. A haploidentical match may be the best option for patients without a closely matched unrelated donor, especially those who urgently need a transplant. Parents and children are haploidentical, and some siblings are haploidentical, so if a child needs a transplant, the child’s parents or partially matched siblings may be able to donate cells.
Each of these methods opens up the option of a potentially life-saving transplant to many more children. To find out more about all stem cell transplant services available through SCCA, contact us toll-free at (855) 557-0555 or by calling (206) 288-SCCA (7222).