Cord Stem Cells: Results, Not Hype.

The stem cells likely to yield the quickest, least expensive, and largest clinical benefit are readily available and present no ethical dilemma. They are umbilical cord blood stem cells.

The controversy surrounding President Bush's decision to fund research involving existing lines of embryonic stem cells has dominated discussions of stem cell research. Yet in the background, umbilical cord blood cells have been steadily delivering verifiable clinical results. The only limit on their availability is the technologic expertise required to separate and store the cells from the umbilicus.

Use of cord stem cells is rapidly expanding in bone marrow transplantation, where the immunologically naive cord blood cells carry a much lower risk of graft-vs.-host disease (GVHD) than occurs with traditional transplants .of adult, marrow-derived stem cells. Investigators also speculate that cord blood stem cells could be used to revitalize a damaged immune system, making them nearly as versatile as fetal stem cells for treating such immune disorders as type 1 diabetes and rheumatoid arthritis.

In the earliest stages of type 1 diabetes, for example, cord blood cell transplants could virtually replace the patient's immune system, preventing complete destruction of the pancreatic islet cells. This approach becomes feasible if the risk to the patient of developing GVHD is low, as it appears to be with cord blood cells.

In hematologic cancers, umbilical cord blood has all the advantages, observed Dr. John E. Wagner Jr., scientific director of clinical research for the blood and marrow transplant program at Fairview-University Medical Center, Minneapolis. Comparisons of matched marrow transplants and unmatched cord blood transplants suggest that the effectiveness is equivalent, but the rate of GVHD is far lower with cord blood.

Until recently, cord blood transplants were reserved for use in children with malignancies, explained Dr. Wagner, director of clinical research at the Stem Cell Institute at the University of Minnesota, Minneapolis. The reasons are largely historical--most of the researchers were pediatricians--but there also was the question of whether a cord blood specimen would contain enough stem cells to reconstitute an adult system.

That concern was put to rest by a recently published study of 68 adults, 54 with malignancies, who received grafts of ...