HONG KONG: There's new hope for children suffering leukemia who cannot find matching donors to provide them with life-giving bone marrow.

Researchers at the Chinese University of Hong Kong (CUHK) have adapted a new treatment procedure, based on a form of treatment called cord blood transplantation (CBT).

Cord blood refers to blood extracted from umbilical cords.

Cord blood, like bone marrow, is a rich source of blood-producing stem cells. CBT has been in practice for about twenty years as treatment of patients requiring bone marrow transplantation (BMT) but who are unable to locate donors.

The method undertaken by CUHK, in cooperation with the Hong Kong Red Cross Blood Transfusion Service (HKRCBTS), was to treat patients with blood extracted from the umbilical cords of two women.

"In theory, infusion of two units of unrelated cord blood could be risky, since there is a potential danger that different cells would act against each other. But experimental results and overseas research lit up our hope. From the perspective of clinical effects, the double-unit unrelated CBT achieved great success," said Chi Kong Li, honorary clinical professor from the Department of Pediatrics at CUHK.

In the university's three-year program, 11 high-risk, acute leukemia patients were treated. In 10 of those patients, successful engraftment of bone marrow was achieved without increased complications. Eight of the patients are still alive. Their leukemia is in remission.

That rate of success using blood from the umbilical cords of women who are unrelated to patients is comparable to improvements achieved in patients given bone marrow transplants.

The treatment also removes the need to carry out long searches and exhaustive procedures to find suitable bone marrow donors. It also overcomes the obstacle of limited availability of stem cells in each separate cord blood unit.

Each unit of cord blood contains insufficient quantities of cells to mount effective treatment. Very little research on the double dosage treatment had been carried out before 2006, when the Department of Pediatrics at the CUHK and HKRCBTS jointly launched the three-year program.

Vincent Lee, clinical assistant professor (honorary) of Department of Pediatrics at CUHK, said survival chances for high risk acute leukemia remains very low - about 5 to 10 percent. It also has become difficult to find identically matched siblings for transplantation given the trend toward small, nuclear families.

Risk are much greater among patients who receive bone marrow transplants from unrelated donors.

Because cord blood cells are "naive cells", strict matching is not necessary and the risk of side effects or infection is very low, said Lee.

(HK Edition 11/06/2009 page1)