Cytokine Generation in Whole Blood, Leukocyte–Depleted and Temporarily Warmed Red Blood Cell Concentrates

Abstract

Background and Objectives: It has been suggested that inflammatory cytokines such as Interleukin (IL)–1β, IL–6, tumor necrosis factor–α (TNF–α) and IL–8 might be responsible for a large number of non–antibody–mediated adverse reactions to the transfusion of blood components, especially of platelet concentrates (PCs). The aim of this study was to compare the levels of proinflammatory cytokines in different blood components containing red cells such as buffy–coat–free packed red cells (RBCs), filtered RBCs and whole blood (WB) during storage under several conditions. Materials and Methods: WB (CPD–A1, n = 16) was stored for 35 days at 2–6°C; samples were taken on days 0, 21 and 35. Buffy–coat–poor RBCs in additive solution PAGGS–M (n = 16) were divided into halves, one half was leukocyte (WBC)–depleted by filtration on day 0, both halves were stored for 49 days at 2–6°C (samples: days 0, 21, 49). Furthermore, buffy–coat–poor, unfiltered SAG–M RBCs (n = 16) were halved immediately after production and stored at 2–6°C until day 42 (samples: days 0, 21, 42). One half remained at room temperature for 24 h on day 3. Cytokine levels were determined with commercial enzyme–linked immunosorbent assays. Results: Levels of IL–1β and TNF–α rose during storage of WB and RBCs. IL–6 could be detected markedly above the detection threshold in WB only. At the end of storage, we detected IL–8 in 1 of 16 units of WB tested, in 10 of 16 standard PAGGS–M RBCs and in 15 of 16 temporarily warmed SAG–M RBCs. Prestorage filtration of RBCs prevented the accumulation of IL–1β and TNF–α. Temporarily warming of RBCs for 24 h did not cause any substantial increase in cytokine levels other than IL–8. RBCs stored in different additive solutions (PAGGS–M versus SAG–M) showed similar cytokine concentrations during storage. The cytokine content of WB was very similar to that of buffy–coat–poor RBCs. Conclusion: Cytokine levels measured in WB and buffy–coat–poor RBCs result in levels which are unlikely to cause febrile reactions even in the case of massive transfusion. We conclude that, according to present knowledge, there is no reason for prestorage filtration of buffy–coat–poor RBCs or WB to avoid febrile transfusion reactions due to cytokine accumulation during storage.