Cytokine release in whole blood assays is inhibited by addition of supernat
ants from stored blood components in a storage time dependent manner. This
is also observed after prestorage leucofiltration of the blood. The role of
erythrocyte changes during storage is unknown. In this study, we have ther
efore used prestorage leucofiltered buffy coat-depleted red blood cells sto
red for 35 days. Assays of whole blood with addition of either complete sus
pension or only supernatant from the stored blood units were stimulated wit
h lipopolysaccharide (LPS) and incubated. Additionally, samples from the st
ored blood units were partly haemolysed and added to similar whole blood as
says. After incubation, tumour necrosis factor-alpha (TNF-alpha) and interl
eukin-10 (IL-10) concentrations were determined. Results showed that the TN
F-alpha release was not changed by addition of supernatants from prestorage
leucofiltered blood, but significantly decreased with addition of red cell
suspension in a storage time dependent manner. The IL-10 release increased
with storage time with addition of both red cell suspension and supernatan
t. The TNF-alpha /IL-10 ratio decreased with storage time, but significantl
y more, 25% vs. 10%, during the 35 days, with addition of suspension compar
ed with addition of supernatant. TNF-alpha and IL-10 release was not change
d by addition of supernatant from lysed erythrocytes of various storage tim
es. Therefore, storage time dependent inhibition of immune response by red
cell suspension may in part be dependent on red cell presentation, and may
cause some of the side effects by transfusion of red cells. (C) 2001 Elsevi
er Science Ltd. All rights reserved.