Researchers target sickle-cell cure. (Biomedicine).

Stem cell transplants have long been a therapy option for children with life-threatening cases of sickle-cell disease, but the procedure itself can be deadly. Researchers in France now report that transplants have cured 30 consecutive patients over several years, thanks largely to an immunity-suppressing drug that has shown only mixed effectiveness in the past. The study of 69 children and young adults began in 1988.

The results document "an unprecedented cure rate for children" with this ailment, says Robert I. Handin of Brigham and Women's Hospital in Boston.

Most of the transplants were of bone marrow. Seven consisted of umbilical cord blood. Like marrow, cord blood contains stem cells, which can develop into various types of blood cells. All the transplants came from siblings of the patients.

In the transplant procedure, doctors first destroy the bone marrow of a patient, clearing the way for a sibling's stem cells to take over and repopulate the person's body with healthy blood cells. A major risk is that the recipient's immune system will attack and kill the implanted cells.

In the study's earlier years, the first 12 children with sickle-cell disease received a bone marrow transplant plus busulfan and cyclophosphamide, two drugs known to facilitate transplants. However, four of these children rejected the cells.

The next 57 patients received these two drugs with their cell transplants plus the immune suppressant, a protein called antithymocyte globulin. These patients fared better, says study coauthor Francoise Bernaudin of Saint Louis Hospital in Paris. Not one patient rejected the cells.

Overall, six patients--all among the first 39 to enter the study--died from complications of stem cell transplants.

Bernaudin presented the research last month in Philadelphia at a meeting of the American Society of Hematology.--N.S.