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Updated: Apr 30, 2026
Routine Screening Method for Microparticles in Platelet Transfusions
Published on: January 31, 2018
The pro-inflammatory potential of microparticles in red blood cell units
M W Kent1, M R Kelher, F B West
1Research Laboratory, Bonfils Blood Center, Denver, Colorado, USA; Department of Pediatrics, University of Colorado, Denver, Colorado, USA.
Background:
Microparticles (MPs) are submicron size cell fragments that are released from cells.
Objectives:
We hypothesise that MPs increase during red blood cell (RBC) storage and are part of the pro-inflammatory activity, which accumulates in the RBC supernatant.
Methods/Materials:
RBC units were separated from whole blood of eight healthy donors: 5 U were split, with 50% undergoing leucoreduction (LR) and the remaining left as unmodified controls. The remaining 3 U were leucoreduced. Samples were obtained at days (D) 1 and 42 and cell-free supernatants separated and stored. The supernatants were centrifuged at 17 000 × g (60 min) or 100 000 × g (120 min) into microparticle-rich (MPR) and microparticle-poor (MPP) portions, resuspended in albumin, incubated with antibodies to CD235 (RBCs), CD45 [white blood cells (WBCs)] and CD41a [platelets (Plts)], and analysed by flow cytometry. Isolated neutrophils were incubated with these samples, and priming activity measured.
Results:
Total MPs increased during storage; however, MPs that marked for precursor cell types did not. Significant priming accumulated in the MPP fraction during storage with some activity present in the MPR fraction from D1 and D42 LR-RBCs.
Conclusion:
Most of the pro-inflammatory priming activity from stored RBCs resides in the MPP supernatant, although the MPR fraction from D42 LR-RBCs does contain some priming activity.
Insights
Microparticle levels increase during red blood cell storage, contributing to inflammation. Most pro-inflammatory activity is found in the microparticle-poor supernatant, not the microparticle-rich fraction.
Area of Science:
- Blood banking and transfusion medicine
- Cellular biology and immunology
Background:
- Microparticles (MPs) are small cell fragments released from cells.
- Red blood cell (RBC) storage can lead to changes in these MPs.
Purpose of the Study:
- To investigate the hypothesis that MPs increase during RBC storage.
- To determine if MPs contribute to pro-inflammatory activity in RBC supernatant.
Main Methods:
- RBC units were stored with and without leucoreduction (LR).
- Supernatants were fractionated into microparticle-rich (MPR) and microparticle-poor (MPP) portions.
- Fractions were analyzed for MP markers and their ability to prime neutrophils.
Main Results:
- Total MPs increased during storage, but specific precursor cell markers did not.
- Pro-inflammatory priming activity accumulated in the MPP fraction during storage.
- Some priming activity was also detected in the MPR fraction of LR-RBCs.
Conclusions:
- The majority of pro-inflammatory priming activity in stored RBC supernatant is in the MPP fraction.
- The MPR fraction from LR-RBCs also shows some priming activity, particularly at later storage times.
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