Febrile reactions to platelet transfusion: the effect of increased interleukin 6 levels in concentrates prepared by the platelet-rich plasma method

Background: A relation between febrile reactions to platelet transfusion and high cytokine levels in platelet concentrates (PCs) was found previously. The levels of cytokines such as interleukin (IL)-6 are related to the while cell content of the PC during storage. Therefore, early removal of white cells should prevent reactions. Study Design and Methods: This prospective study was set up to compare methods for the preparation of random PCs, the platelet-rich plasma method (PRP-PCs), which results in a high white cell content, and the buffy coat method (BC-PCs), which results in a low white cell content, with regard to the frequency and severity of reactions to platelet transfusion and the IL-6 level of the PC. IL-6 was chosen because it is the major mediator of the acute-phase response. White cells were reduced in all PCs before transfusion. Results: Platelet transfusions (n = 584) in 64 patients were studied. An overall reaction frequency of 7.2 percent was observed. Transfusion reactions were seen predominantly in patients who received PRP-PCs (PRP-PCs: 9.3% vs. BC-PCs: 2.7%, p = 0.007). Allergic reactions were limited to transfusions of PRP-PCs. The following PRP-PC characteristics were significantly correlated with febrile transfusion reactions: IL-6 level (p < 0.0001), initial white cell count (p = 0.001), and storage time (p = 0.02). In this group, reactions were less frequent in patients receiving pretransfusion medication (p < 0.001). In the PRP-PC group, IL-6 content (p = 0.01) and initial white cell count (p = 0.04) were also significantly correlated with allergic reactions, which indicated that these or associated factors might have an effect on the outcome of this type of reaction. Conclusion: Febrile reactions are highly correlated with IL-6 levels in PCs. The low white cell content of BC-PCs is associated with undetectable IL-6 levels and a reduced frequency of febrile as well as allergic reactions in recipients. The BC method is the preferable one for the production of random-donor PCs.