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Adverse Outcomes in Blood and Blood Component Therapy - page 6 / 19





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FNHTR in 39 cases, allergic in 13, delayed hemolytic in 19, and miscellaneous in 7. In the first half of 2000, 32 reactions (0.20%) were reported for 16,093 prestorage leukocyte reduced RBC transfusions. These consisted of 13 FNHTRs and 10 allergic, 7 delayed hemolytic, and 2 miscellaneous reactions. They noted that the use of prestorage leukocyte reduced RBCs did not significantly affect the rate of reactions classified as allergic (0.04% in 1999; 0.06% in 2000) or as FNHTR (0.12% in 1999; 0.08% in 2000). For all patients, universal leukocyte reduction in 2000 did not reduce the rate of FNHTR from the rate seen with selective bedside leukocyte reduction, which was the practice used in 1999 (0.12% in 1999; 0.08% in 2000). They concluded that no significant difference was found in the incidence of transfusion reactions in patients receiving prestorage leukocyte reduced RBCs and non-leukocyte RBCs. In addition, they found no difference in transfusion reaction rates when periods of prestorage universal leukocyte reduction were compared to those of selective leukocyte reduction.19 Prestorage filtration is probably best for preventing FNHTR in platelet transfusion.18 Bedside filtration may not have any effect on the prevalence of FNHTR when it is used for platelet transfusions, possibly because cytokines may already have been released into the product prior to transfusion. In addition, bedside leukocyte reduction filters have been shown to cause episodes of significant hypotension, especially in patients treated with angiotensin-converting enzyme inhibitors.19  

Kluter et al17, investigated transfusion reactions with regard to the residual leukocyte content in the stored platelet concentrate in two consecutive study periods. In the first study period, they reduced the leukocytes in the PCs by bedside filtration. In the second period, they filtered all PCs before storage. They examined recipients who experienced transfusion reactions with regard to their main clinical symptoms during and after transfusion. They analyzed concentrations of IL-1, IL-6, IL-8, TNF-, macrophage inflammatory protein-1 alpha, and RANTES in the supernatant of the implicated PCs. The result showed that the incidence of transfusion reactions remained steady when the transfusion regimen was changed from bedside filtration to prestorage leukocyte filtration. The transfusion reactions experienced in both periods were mostly of allergic origin. They detected the inflammatory cytokines; IL-1, IL-6, IL-8, and TNF- in only a minority of the PCs involved in the transfusion reactions. However PCs involved in allergic reactions contained high concentrations of RANTES. They concluded that prestorage leukocyte filtration did not reduce the incidence of the reactions and that inflammatory cytokines were of minor relevance. The RANTES, which accumulates even in leukocyte -reduced PCs, was associated with allergic transfusion reactions thus the platelet-derived mediators may be a key to understanding non-hemolytic transfusion reactions.17,20

In a study to determine whether increased cytokine levels in PCs are responsible for FNHTR Muylle et al.21, measured several cytokine levels in PC at various times of storage up to 7 days. They found increased levels of IL-6 in 8 of 12 PCs after 3 days of storage and in 10 of 12 PCs after 5 and 7 days of storage. Several of the PCs with increased IL-6 levels also showed increased TNF- and IL-1 levels. They observed that the increased levels of the cytokines were present when the leukocyte count in PCs exceeded 3 X109/L. When they compared the levels of the TNF-, IL- 1, and IL-6 in samples taken at various storage times the result indicated that the increased levels were the result of active synthesis and release of interleukins during storage. In the second part of the study, they evaluated 45 patients receiving leukocyte-reduced PCs for transfusion reaction. Six of 45 platelet transfusions had complicating febrile reactions. All six PCs that caused reactions showed significantly higher levels of TNF- and IL-6 than PCs not causing reactions. Their findings indicate that transfusion reactions might be due to the intravenous administration of plasma with high cytokine levels and might not always result from an antigen-antibody reaction.21 In another study, Heddle et al.22, investigated whether substances in the plasma or the cells in the product cause reactions to transfused platelets. They separated standard platelet concentrates into their plasma and cellular components and then transfused both portions in random order. They monitored patients for reactions during all transfusions. They measured the concentration of IL-1 and IL-6 in the platelet products before each transfusion. They performed studies on the platelet products to determine the effect of storage on the concentration of the cytokines. The result showed a strong positive correlation between the reactions and the

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