INCREASED TUMOR-NECROSIS-FACTOR-ALPHA (TNF-ALPHA), INTERLEUKIN-1, AND INTERLEUKIN-6 (IL-6) LEVELS IN THE PLASMA OF STORED PLATELET CONCENTRATES - RELATIONSHIP BETWEEN TNF-ALPHA AND IL-6 LEVELS AND FEBRILE TRANSFUSION REACTIONS

Increased interleukin 6 (IL-6) levels were found in 8 of 12 platelet concentrates (PCs) after 3 days of storage and in 10 of 12 PCs after 5 and 7 days of storage. Most of the PCs with an increased IL-6 level also showed increased tumor necrosis factor alpha (TNFalpha) and interleukin 1beta (IL-1beta) levels. Levels of IL-6 increased by 3 log10 over the base level during storage. Increased levels were found when the PC white cell count exceeded 3 x 10(9) per L. A linear correlation was found among the levels of TNFalpha, IL-1beta, IL-1alpha, and IL-6 in the PCs (r >0.885). Comparison of the TNFalpha, IL-1beta, and IL-6 levels in samples taken at various storage times indicates that the increased levels are the result of an active synthesis and release of interleukins during storage. In a second part of the study, 45 transfusions of white cell-reduced PCs were studied. Six transfusions were complicated by a febrile reaction. These reactions were related to high levels of IL-6 and TNFalpha in the PCs (p<0.0001). These cytokines are known as endogenous pyrogens. These 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.