Background:
More granulocyte concentrates (GCs) could be produced for
more patients from the same donor if apheresis bags were split and stored for
longer periods of time. Hence, we tested the hypothesis that splitting and
extension of storage of GCs do not impair granulocyte function or viability.
Study Design and Methods:
Granulocyte apheresis concentrates were produced
using modified fluid gelatin as a separation enhancer, split into two portions, and
stored for 24 and 48 h. Granulocyte function, represented by cell migration, reactive
oxygen species (ROS) production, and neutrophil extracellular trap formation
(NETosis), was measured by live-cell imaging. ROS production, adhesive surface
protein expression, and viability were measured by flow cytometry.
Results:
Splitting had no effect on any of the tested parameters. After 24 h of
storage, live-cell imaging showed no significant difference in migration, time
to maximum ROS production, time to half-maximum NETosis, viability, or
CD11b expression, but ROS production induced by phorbol 12-myristate
13-acetate (PMA) decreased from an initial median fluorescence intensity of
1775–590 artificial units. After 48 h, PMA-induced ROS production, viability,
and migration declined, as reflected by decreases in median total distance
(119 vs. 63.5 μm) and median Euclidean distance (30.75 vs. 14.3 μm).
Conclusion:
Splitting GC products has no effect on granulocyte viability or
function, but extended storage >24 h does compromise granulocyte function.
The findings confirm that GCs should be transfused within 24 h of collection.
Longer storage cannot be recommended.