Observational studies

Project leaders: Anske van der Bom MD PhD and Prof Dick J van Rhenen MD PhD

TRALI

Transfusion Related Acute Lung Injury (TRALI) is the leading cause of transfusion related mortality. A study aiming to quantify the contribution of female and allo-exposed blood donors, both as markers for leukocyte antibodies, to the occurrence of TRALI (project leaders: JG van der Bom, E Briët) started in 2006 in cooperation with the Department of Clinical Epidemiology at the Leiden University Medical Center. The key finding in this project is the observation that allo-exposed donors of plasma rich products (FFP or the plasma unit of donor platelets) confer an increased risk of TRALI, while allo-exposed donors of plasma poor products (in RBC or platelets) do not. The overall percentage of TRALI cases that could have been prevented by the deferral of all allo-exposed donors (irrespective of product type) was 51% (95% CI: 14% - 88%).

Further results from the project include determination of leukocyte antibody prevalences in subgroups of allo-exposed and non-allo-exposed donors. Overall the conclusion from the project is that the male-only plasma measure prevents a substantial part of all TRALI, but plasma poor products still cause TRALI in leukocyte antibody independent ways. Donor leukocyte reactive antibodies were shown to activate cognate recipient neutrophils, which cause vascular injury by the release of oxygen radicals. Donor leukocyte reactive antibodies (against HNA, HLA class I+II) are mainly found in (multiparous) female donors. As a precautionary measure only plasma from non-transfused male donors is used for single donor Fresh Frozen Plasma in the Netherlands since July 2007 in order to eliminate antibodies able to activate cognate recipient neutrophils, which cause vascular injury by the release of oxygen radicals. Such donor leukocyte reactive antibodies are mainly found in (multiparous) female donors.

In the TRALI syndrome study (project leaders: DJ van Rhenen, EAM Beckers) from January 2005 till January 2009 all TRALI cases reported to Sanquin Blood Bank were investigated for patient, donor and product characteristics. Despite the precautionary measure of male-only plasma, the frequency of TRALI reports did not change; possibly because of the higher awareness of TRALI. In addition, non-immune causes might be more important, which are obviously not influenced by male-only plasma polices. In our series, despite extensive and deliberate testing for incompatible (HNA, HLA class I and II) donor antibodies, the majority (40/75) consisted of non-alloimmune TRALI cases.

Key publications