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

BACKGROUND: From 1991 through 1996, nine transfusion-related cases of septicemia and endotoxemia occurred in New Zealand, a rate approximately 80 times that in the United States. Eight cases involved the transfusion of Yersinia enterocolitica-infected blood and one involved Serratia liquefaciens-infected blood. Six of the recipients died. Donor exclusion by recent gastrointestinal illness failed to prevent the four most recent such infections, and it has led to an estimated 3- to 5-percent rate of donor deferral. STUDY DESIGN AND METHODS: An antigen preparation containing the released proteins (Yops) of Y. enterocolitica was used to establish an EIA to detect IgA directed against these proteins in donated blood. The assay was tested with serum from donors in transfusion-related endotoxemia cases, subjects who were stool culture-positive for Y. enterocolitica, and 495 healthy volunteer blood donors. RESULTS: The assay detected anti-Yop IgA in the donors of all 6 infected units tested. Ninety-six percent of culture-positive subjects tested positive, whereas there was 70-percent positivity with a commercial immunoassay based on lipopolysaccharide. Five percent of random donors tested positive; only one of these had Y. enterocolitica present in a stool sample, and none were bacteremic. CONCLUSION: The anti-Yop immunoassay used in this study could be applied to reduce the risk of posttransfusion endotoxic shock caused by Y. enterocolitica.