Prestorage leucofiltration of red blood cell suspensions modulates storagetime-dependent suppression of in vitro cytokine release

Background: Leucocyte- and platelet-derived bioactive substances accumulate d in blood preparations during procession and storage may play a role in si de-effects, including immunosuppression, observed after transfusion. Leucod epletion by filtration may significantly reduce the a mount of storage time -dependent accumulated substances. Therefore we studied the effect of pre-s torage leucofiltration of red blood cell suspensions on stimulation of tumo ur necrosis factor-alpha (TNF-alpha) and interleukin-2 (IL-2) release in vi tro. Materials and Methods: Nine units of CPDA-1 blood (whole blood suspend ed in citrate phosphate dextrose adenine-1), 9 units of pre-storage leucofi ltered CPDA-1 blood, 9 units of SAGM blood (buffy coat-depleted red blood c ells suspended in saline adenine glucose mannitol) and 9 units of pre-stora ge leucofiltered SAGM blood were stored for 35 days. Supernatants were coll ected from all units after storage for 1, 21 and 35 days. Assays of whole b lood obtained from healthy volunteers with addition of supernatants from st ored blood components were stimulated with lipopolysaccharide (LPS) or phyt ohemagglutinin A (PHA) and incubated for 24 h or 72 h. Control assays witho ut addition of supernatants from stored blood components were run simultane ously. After incubation TNF-alpha and IL-2 concentrations were determined b y ELISA methods in assay supernatants. Results: The stimulated TNF-alpha an d IL-2 releases were significantly decreased by supernatants from CPDA-1 bl ood and SAGM blood in a storage time-dependent manner compared with release in control assays. Pre-storage leucofiltration of CPDA-1 blood improved TN F-alpha release significantly while leucofiltration of SAGM blood increased the release to concentrations higher than that observed in control assays. However, pre-storage leucofiltration had no effect on storage time-depende nt decreased IL-2 release. Conclusion: Pre-storage leucofiltration may impr ove certain in vitro immune responses impaired by supernatants from stored blood white others appear to be unaffected.