Specificities of leucocyte alloantibodies in transfusion-related acute lung injury and results of leucocyte antibody screening of blood donors.

BACKGROUND: Antibody-mediated transfusion-related acute lung injury (TRALI) is an important cause of transfusion-associated morbidity and death. Preventive strategies are currently a matter of debate.
METHODS: Specificities of leucocyte antibodies implicated in previous severe TRALI reactions were determined using standard techniques. Based on these results, a leucocyte antibody screening strategy for the testing of parous female donors was introduced.
RESULTS: Of 36 TRALI cases, 17, 12, four and three were due to human leucocyte antigen (HLA) class II, human neutrophil alloantigen (HNA), HLA class I, and mixtures of HLA class I and II antibodies, respectively. HNA-3a antibodies accounted for 10 of 12 HNA antibody-mediated reactions and 6 of 10 fatalities including one after transfusion of red blood cells. Investigation 5332 parous female donors showed leucocyte antibodies in 473 samples, resulting in an alloimmunization rate of 8.9%. Sixty-one per cent of these donors presented HLA class I, 19% class II, 12% HLA class I and II antibodies and 5% HNA antibodies. Additional HLA class I antibodies were found in 39% of HLA class II and in 17% of HNA antibodies containing sera. Our restrictive plasma strategy did not result in a shortage of plasma or platelets. No antibody-mediated TRALI case was observed since introduction of the policy of plasma from male, nulliparous or tested multiparous donors.
CONCLUSION: Compared to HLA class I antibodies, those directed against HLA class II and HNA-3a were of greater clinical relevance. Isolated HLA class I antibody screening was found to be insufficient for leucocyte antibody screening.