FAILURE TO KILL YERSINIA-ENTEROCOLITICA BY PLASMA DILUTED TO THE CONCENTRATION FOUND IN RED-CELL UNITS

The possibility that the use of additive solutions for red cell storag e might impair the ability of plasma to kill Yersinia enterocolitica w as investigated by studying killing of Y enterocolitica by neat and di luted plasma. The ability of neat citrated plasma to kill complement s ensitive organisms was lost at around 26%, the dilution typically foun d in red cell units. These results should be considered in the light o f evidence that killing in plasma is important in the protection of do nated blood against growth of Y enterocolitica, and the observation th at the increase in frequency of transfusion reactions caused by Y ente rocolitica coincided with the widespread introduction of additive solu tions. Taken together, these points support the suggestion that the in troduction of additive solutions may have precipitated the problem of growth of Y enterocolitica in stored blood.