Background: In contrast to the well-documented effect of white blood cells on the quality of red blood cells (RBCs), the effect of platelets (PLTs) has received little consideration. In this study, the PLT content and level of PLT-derived cytokines in RBCs prepared using different types of leukoreduction methods were investigated.
Study design and methods: Buffy coat-poor RBCs and five types of leukofiltered (LF) RBCs, including RBCs prepared with a whole blood (WB) PLT-saving filter, were prepared and stored according to standard blood bank conditions. PLT content was measured on Day 1, and levels of PLT-derived cytokines were measured by enzyme-linked immunosorbent assay at nominated timepoints during 42 days of storage.
Results: The PLT content of leukoreduced RBCs varied widely depending on the processing method and/or leukoreduction filter used, with some types of RBCs containing very low PLT counts while other units contained PLT counts comparable to those of unprocessed WB. The PLT content of RBCs directly influenced the concentration and accumulation of PLT-derived cytokines. Several PLT-derived factors exhibited significant accumulation throughout 42 days of storage. RBCs with high PLT content exhibited concentrations of RANTES (CCL5) and soluble CD40 ligand equivalent to those previously reported to show significant biologic and clinical effects.
Conclusion: The PLT content and levels of PLT-derived cytokines in leukoreduced RBCs are influenced by the processing method and types of leukoreduction filters used. It may be inappropriate to consider LF-RBCs prepared with different types of leukoreduction filters as equivalent products based on their differing levels of PLT factors.