While the child's age and symptom severity at the time of transplant are crucial to determining outcome, the source of stem cells is also important, said Kurtzberg.
Cord blood appears to provide a better and faster correction of enzyme deficiencies than does adult bone marrow, she said. Stem cells from cord blood travel to the brain more rapidly than stem cells from adult bone marrow, and cord blood stem cells repair deficiencies in both the central and peripheral nervous systems, said Kurtzberg.
Thus, disease progression stabilizes about 2 to 4 months earlier in patients who receive cord blood compared to those who receive adult bone marrow, and huge developmental milestones occur during that period of infancy, said Kurtzberg.
The ease of obtaining cord blood also makes it an excellent source of stem cells, she said. Cord blood is readily available because it is extracted from discarded placentas (afterbirth) following child birth. Adult bone marrow must be harvested from living donors through an invasive surgical procedure.
Finally, cord blood cells are less mature than adult bone marrow cells and thus do not need to perfectly match the patient's immune-related blood proteins, called antigens, said Kurtzberg. Only four of six cord blood "antigens" must match for a transplant to have a reasonable chance of success, whereas adult bone marrow requires a greater degree of matching antigens, she said.
As a result, a cord blood donor unit can be identified and obtained within a week, whereas a matching adult donor can takes months to locate and obtain if available at all, said Kurtzberg.
Similar benefits of cord blood were seen in an earlier Duke study of children with Hurler Syndrome, results of which were published in the May 6, 2004, issue of the New England Journal of Medicine. In that study, Kurtzberg's team