The New England Region is currently participating in the Leukocyte Antibodies Prevalence (LAP) Study, a multi-center research study sponsored by the National Institutes of Health. The LAP Study seeks to determine how common antibodies to white blood cells (leukocytes) are in the donor population. These antibodies in donor’s blood are considered the primary cause of Transfusion-Related Acute Lung Injury, or TRALI, in blood recipients. Although TRALI is a rare condition, it is a leading cause of transfusion-related deaths in the United States. Blood recipients who develop TRALI experience difficulty breathing due to serious injury to their lungs following blood transfusion, especially of products with high volumes of plasma, the liquid portion of the blood. Most patients who experience a TRALI reaction do survive, but it may be fatal up to 10 percent of the time.

There are no good counts of how frequent TRALI reactions are in blood recipients, but it is clear that antibodies to leukocytes are not the only cause. It is important to note that these antibodies cause no harm to the individual donors who carry them, nor to most of the blood recipients who receive blood with these antibodies. Such antibodies tend to be more common in women who have been pregnant, or in men or women who have received another person’s blood. The New England Region of the American Red Cross is recruiting 185 untransfused men, 185 transfused men, and 955 women with varying pregnancy histories so as to estimate how common these leukocyte antibodies are in our donor population. The other five blood centers participating in the NIH-funded REDS program (Retrovirus Epidemiology Donor Studies) are collecting the same numbers, so the large sample size and diverse geography of the centers should provide a good snapshot of the U.S. donor population. The American Association of Blood Banks (AABB) has recently issued guidance recommendations to blood centers like the American Red Cross with the aim of reducing the number of TRALI cases each year. Options range from altering the types of blood products collected from certain donors to testing at least some donors for the presence of these antibodies. While more research is needed to understand the biological reactions that provoke TRALI, it is felt that some interventions might meanwhile reduce the risk even while the etiology is being worked out.

The REDS Research Department has been conducting the LAP Study since October 2006 and expects to complete donor enrollment by June. Antibody testing is underway, and should also be completed later this year.

Medical Update