Identification of Yersinia-infected blood donors by anti-Yop IgA immunoassay

BACKGROUND: From 1991 through 1996, nine transfusion-related cases of septi cemia and endotoxemia occurred in New Zealand, a rate approximately 80 time s that in the United States. Eight cases involved the transfusion of Yersin ia enterocolitica-infected blood and one involved Serratia liquefaciens-inf ected blood. Six of the recipients died. Donor exclusion by recent gastroin testinal illness failed to prevent the four most recent such infections, an d it has led to an estimated 3- to 5-percent rate of donor def ferral. STUDY DESIGN AND METHODS: An antigen preparation containing the released pr oteins (Yops) of Y. enterocolitica was used to establish an EIA to detect I gA directed against these proteins in donated blood. The assay was tested w ith serum from donors in transfusion-related endotoxemia cases, subjects wh o were stool culture-positive for Y enterocolitica, and 495 healthy volunte er blood donors. RESULTS: The assay detected anti-Yop IgA in the donors of all 6 infected un its tested. Ninety-six percent of culture-positive subjects tested positive , whereas there was 70-percent positivity with a commercial immunoassay bas ed on lipopolysaccharide, Five percent of random donors tested positive; on ly one of these had Y enterocolitica present in a stool sample, and none we re bacteremic. CONCLUSION: The anti-Yop immunoassay used in this study could be applied to reduce the risk of posttransfusion endotoxic shock caused by Y enterocolit ica.