THE ROLE OF THE PLASMA FROM PLATELET CONCENTRATES IN TRANSFUSION REACTIONS

Background. Febrile, nonhemolytic transfusion reactions are the most f requent adverse reactions to platelets. A number of observations argue against the widely held view that these reactions result from the int eraction between antileukocyte antibodies in the recipient and leukocy tes in the platelet product. We sought to determine whether substances in the plasma or the cells in the product cause reactions to transfus ed platelets. Methods. We separated standard platelet concentrates int o their plasma and cellular components and then transfused both portio ns in random order. Patients were monitored for reactions during all t ransfusions. Before each transfusion, the concentration of cytokines ( interleukin-1 beta and interleukin-6) was measured in the platelet pro ducts. Studies were also performed on the platelet products to determi ne the effect of storage on the concentration of cytokines. Results. S ixty-four pairs of platelet-product components (the plasma supernatant and the cells) were administered to 12 patients. There were 20 reacti ons to the plasma supernatant and 6 reactions to the cells (chi-square = 6.50, P = 0.009). Eight transfusions were associated with reactions to both products. The plasma component was more likely to cause sever e reactions than the cells (chi-square = 9.6, P < 0.01). A strong posi tive correlation was observed between the reactions and the concentrat ion of interleukin-1 beta and interleukin-6 in the plasma supernatant (P < 0.001 and P = 0.034, respectively). In vitro studies demonstrated that interleukin-1 beta and interleukin-6 concentrations rise progres sively in stored platelets and that these concentrations are related t o the leukocyte count in the platelet product. Conclusions. Bioreactiv e substances in the plasma supernatant of the platelet product cause m ost febrile reactions associated with platelet transfusions. Removing the plasma supernatant before transfusion can minimize or prevent thes e reactions.