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Updated: Nov 28, 2025
Routine Screening Method for Microparticles in Platelet Transfusions
Published on: January 31, 2018
HLA molecule expression on the surface of cells and microparticles in platelet concentrates
Louise Pannetier1,2,3, Marie Tamagne1,2,3, Thibaut Bocquet2
1Univ Paris Est Creteil, INSERM, IMRB, Creteil, France.
Background:
Platelet (PLT) transfusions are an essential treatment for bleeding disorders. However, immunologic complications can occur, including alloantibody production against Class I HLA molecules. The principal source of HLA molecules in PLT concentrates (PCs) is the PLTs themselves. However, extracellular microparticles (MPs) present in PCs may express HLA molecules.
Study Design And Methods:
We used nanoscale flow cytometry to explore the expression of HLA-A2, HLA-B7, and HLA-B57 on the surface of cells, PLT-derived MPs (PMPs), lymphocyte-derived MPs (LMPs), and monocyte-derived MPs (MMPs) present in PCs. Expression was studied during 7 days of storage.
Results:
Platelets were not the only source of HLA molecules in PCs. HLA molecules were present on PMPs, LMPs, and MMPs. The level of HLA Class I molecule expression varied between haplotypes and MPs of different origins and during storage.
Conclusion:
Platelets or residual cells remaining after leukoreduction are not the only source of HLA Class I molecules in PCs, highlighting the contribution of MPs to alloimmunization mechanisms. These data may be relevant for the development of new transfusion guidelines.
