The results from one of the largest studies to date of patients undergoing bone marrow transplantation from unrelated donors were published Aug. 2.

The study, led by University researchers along with 16 other institutions in the United States, aimed to improve bone marrow transplant survival rates by looking at ways to prevent graft-versus-host disease, a potentially lethal complication for people who have had bone marrow transplants.

The study monitored 410 patients, including 103 from the University, for an average of 4.2 years and up to seven years. It studied the patients after they received bone marrow transplants to treat cancers such as lymphoma and leukemia. The treatment is also used for other diseases such as bone marrow diseases and immunodeficiency disorders.

Graft-versus-host disease is caused by cells known as T-cells, a type of white blood cell. In bone marrow, they attack the transplant patient’s body, which is a frequent problem, according to the study. Severity varies from mild to life-threatening, and the disease and its treatment can have a profound effect on quality of life, the report said.

In one treatment, doctors physically remove T-cells with machines or antibodies, a process known as T-cell depletion. In another treatment, drugs prevent T-cells from functioning.

John Wagner, the study’s lead investigator and a University professor, said he concluded T-cell removal is effective at preventing graft-versus-host disease, but did not extend survival rates beyond that observed with drug therapy. Patients remained at high risk of infection regardless of the treatment used and the ability to prevent graft-versus-host disease, Wagner said.

Graft-versus-host disease is when T-cells recognize the patient as foreign and attack various parts of the body, he said. While the research team hoped the prevention of graft-versus-host disease might be beneficial, in terms of survival, the team observed higher risk of viral infections, he said.

“I think the first thing the study tells us is that prevention of GVHD itself is not the answer – high risk of infection is the principle obstacle to overcome and this is the result of an impaired immune system,” Wagner said. “New strategies are currently being investigated such as new drug combinations, new methods of T-cell removal and use of umbilical cord blood, left over in afterbirth after a baby is born.”

Michael R. Bishop, investigator at the National Cancer Institute, said the results don’t significantly change the future of bone marrow transplantation because T-cell depletion still shows instances of cancerous relapse and viral infections.

“By trying to reduce one problem, you get another problem and, at the end of the day, both (types of treatment) do as well as the other,” he said.