Panel backs strategy to reduce transfusion-related lung injury.
At a meeting of the FDA's Blood Products Advisory Committee in April, the panel agreed in a 13 to 0 vote that the use of predominantly male plasma for transfusions would reduce the incidence of transfusion-related acute lung injury (TRALI), the leading cause of transfusion-related deaths reported to the FDA over the past 3 years.
TRALI is defined as an acute syndrome with severe shortness of breath within 4-6 hours of a transfusion, with no signs of fluid overload, bilateral pulmonary infiltrates on chest x-ray, and changes in arterial oxygenation, in the absence of other detectable causes. If recognized early enough, TRALI is treatable and symptoms usually resolve within 24-48 hours, but the reported mortality rate ranges from 10% to 50%, according to the FDA.
TRALI cases have been associated with plasma from female donors, which is thought to be related to the presence of allotypic leukocyte antibodies in donors, stimulated by pregnancy and transfusions. Because donors implicated in cases of TRALI in recipients have often been women with leukocyte antibodies, reducing the use of such donors has been considered as a strategy for reducing TRALI, according to the FDA. In the United Kingdom, the incidence of TRALI dropped dramatically after 2003, when the National Blood Service decided to use mostly male plasma for transfusions. In the U.S. blood banking community, this approach has been implemented voluntarily or is under consideration.
The panel largely agreed that this approach would not affect the U.S. supply of plasma. But Dr. Irma Szymanski, professor of pathology at the University of Massachusetts, Worcester, said that while there is evidence of an association between plasma from female donors and a greater risk of TRALI, plasma from some female donors has not been associated with TRALI cases, and they should not be eliminated from the donor pool. And Dr. Maureen Finnegan, of the department of orthopedic surgery at the University of Texas at Dallas, added that a plasma shortage could occur in the event of a national disaster that presented increased demand.
The panel unanimously agreed that although some preliminary data suggest an association between increased TRALI risk in recipients and the presence of antineutrophil and anti-human leukocyte antigen (HLA) antibodies in donors, it is too early to recommend screening donors for these antibodies. More data are anticipated from ongoing studies, including a National Institutes of Health-sponsored 5-year study on the prevalence of HLA and granulocyte antibodies in blood donors at U.S. blood centers. The study will correlate the presence of HLA class 1 and 2 antibodies in blood donors with certain factors, such as the number of pregnancies and lifetime history of transfusion, in over 5,000 female donors and in men with and without a history of blood product transfusion.
In another unanimous vote, the panel did not support eliminating the use of plasma from donors with a history of transfusions, because currently there is no evidence that this strategy would reduce the incidence of TRALI.
One of the speakers at the meeting, Dr. Ravi Sarode, director of transfusion medicine at the University of Texas at Dallas, said that there is widespread misuse of plasma in clinical practice and that reducing inappropriate use of plasma would also decrease the incidence of TRALI. For example, protamine is the appropriate treatment for heparin-induced bleeding, but many surgeons continue to prescribe fresh frozen plasma, which may make bleeding worse, he said.
While all blood products that are transfused have been implicated in TRALI, most cases are associated with plasma products, such as fresh frozen plasma.
After a previous meeting of the same panel, the FDA issued a letter to physicians about TRALI in October 2001. Reports of TRALI subsequently increased: 21 deaths were reported between October 2003 and September 2005, and 35 deaths were reported in 2006.
Those 35 deaths accounted for 51% of all reported transfusion-related fatalities that year. TRALI-related morbidity is much higher, occurring at a rate of one case per 2,500 to 5,000 transfusions, according to FDA estimates.
BY ELIZABETH MECHCATIE
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|Title Annotation:||Clinical Rounds|
|Publication:||Internal Medicine News|
|Date:||Jun 15, 2007|
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