Prestorage versus bedside white blood cell filtration of red blood cell concentrates: effects on the content of cytokines and soluble tumor necrosis factor receptors.

Background : The cytokine network has important implications for the systemic inflammatory and metabolic response in trauma and infection. The objective of this study was to investigate the influence of white blood cell (WBC) filtration on the cytokine content in red blood cell concentrates (RBCs). Study Design and Methods : Tumor necrosis factor-α (TNF), interleukin-1-β (IL-1), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), and soluble TNF receptors I and II (sTNF-RI, sTNF-RII) were investigated in filtered and nonfiltered RBCs during storage. After 40 days of storage the originally nonfiltered units were filtered. Results : On day 1 prestorage filtered RBCs had lower concentrations of WBCs (p < 0.001), TNF (p < 0.01), sTNF-RI (p < 0.01) and sTNF-RII (p < 0.05) compared to nonfiltered units. IL-1 concentrations increased from day 1 to day 40 (p < 0.05) in nonfiltered RBCs and were higher in nonfiltered units compared to prestorage filtered ones on day 40 (p < 0.05). An increase of IL-8 was found in nonfiltered RBCs as well as prestorage filtered units from day 1 to day 40 (p < 0.05) but the concentrations of IL-8 were higher in nonfiltered units on day 40 compared to prestorage filtered units (p < 0.05). Filtration at the end of the 40-day storage period had no influence on the concentrations of cytokines and soluble TNF receptors. Conclusion : The present results suggest that prestorage WBC filtration may be more efficient in reducing the cytokine content of RBCs compared to filtration at the end of the storage period. The clinical impact of passive transfer of components of the cytokine network via RBCs, e.g., in critically ill patients, is however unclear and needs further investigations.