Sickle cell disease is an inherited blood disorder affecting red blood cells that contain hemoglobin, a substance that carries oxygen from the air in the lungs to all parts of the body. In patients with this disease, red blood cells contain an abnormal type of hemoglobin that causes the normally round, flexible red blood cells to become sickle- or crescent-shaped. The sickle cells can't pass through tiny blood vessels, preventing blood from reaching the body's tissues, which can result in tissue and organ damage, pain and stroke.

Sickle cell disease affects about 70,000 people in the United States. It occurs in about 1 of every 500 African-American births and 1 of every 1,000 to 1,400 Hispanic-American births. While there is no cure for the disease, blood transfusions and bone marrow transplants have been shown to be effective treatments by replacing short-lived sickle cells with longer-lived healthy red blood cells, although bone marrow transplants have a 10 percent mortality rate because of the possibility of rejecting the bone marrow, complications such as seizures and a high risk of infection.

In the study, brain lesions in six patients shrank after two years of regular blood transfusions, and no new silent strokes occurred. One patient had a lesion disappear, however, that patient did not continue with further blood transfusions, and the lesion returned at more than three times its original size, suggesting the need for prolonged transfusions. A lesion grew larger in the seventh patient.

Many of the lesions occur in the frontal lobe of the brain, which controls the cognitive function or problem-solving area, or in the occipital lobe, which controls the visual processing center, King said. Neuroradiologists can locate the lesions using magnetic resonance imaging (MRI).

"Because these lesions are usually in the frontal lobe, it is important to do cognitive testing on these children to determine any impairment," King said. "We hope that by preventing further lesions through blood transfusions that we can preserve their ability to think and learn."

A total of 71 percent of the school-aged children in the study were receiving special education services and 57 percent had failed a grade in school. Previous School of Medicine research shows that 80 percent of students with silent strokes perform poorly in school.

King said the results of the trial were encouraging to health-care professionals treating children with sickle cell disease.

"What we found in this trial is that families and children with sickle cell disease and who experience silent strokes are willing to commit to blood transfusion therapy for this condition," King said. "If these children are left untreated, their risk for an overt stroke is very high, but if we use blood transfusion therapy, they may have a lower risk for overt stroke and no evidence of new silent infarcts on an MRI."

Results of this Phase II trial spearheaded a larger, Phase III study that is evaluating 1,800 children in the United States, Canada and Europe. That trial, called the Silent Cerebral Infarct Multi-Center Clinical Trial, is headed by Michael R. DeBaun, M.D., professor of pediatrics at the School of Medicine. Through it, researchers will further determine the effectiveness of blood transfusion therapy to prevent silent strokes in children with sickle cell disease and to prevent further cerebral injury.

King A, Noetzel M, White D, McKinstry R, DeBaun M. Blood transfusion therapy is feasible in a clinical trial setting in children with sickle cell disease and silent cerebral infarcts. Pediatric Blood and Cancer. Published online Sept. 18, 2007.

This study was funded by a grant from the Doris Duke Charitable Foundation.

Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.