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Red blood cell microparticles show altered inflammatory chemokine binding and release ligand upon interaction with platelets

Authors

  • Zeyu Xiong,

    1. From the Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine; the Department of Pathology; the Center for Biologic Imaging, Department of Cell Biology and Physiology; and the Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
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  • John Cavaretta,

    1. From the Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine; the Department of Pathology; the Center for Biologic Imaging, Department of Cell Biology and Physiology; and the Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
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  • Lirong Qu,

    1. From the Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine; the Department of Pathology; the Center for Biologic Imaging, Department of Cell Biology and Physiology; and the Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
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  • Donna Beer Stolz,

    1. From the Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine; the Department of Pathology; the Center for Biologic Imaging, Department of Cell Biology and Physiology; and the Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
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  • Darrell Triulzi,

    1. From the Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine; the Department of Pathology; the Center for Biologic Imaging, Department of Cell Biology and Physiology; and the Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
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  • Janet S. Lee

    1. From the Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine; the Department of Pathology; the Center for Biologic Imaging, Department of Cell Biology and Physiology; and the Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
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  • This work was supported by HL086884, Hemostasis and Vascular Biology Grant, and the Department of Medicine Junior Scholar Award.

Janet S. Lee, Division of Pulmonary, Allergy, Critical Care Medicine, NW628 Montefiore Hospital, 3459 Fifth Avenue, Pittsburgh, PA 15213; e-mail: leejs3@upmc.edu.

Abstract

BACKGROUND: Storage of red blood cells (RBCs) under standard blood bank conditions results in reduced structural integrity leading to membrane budding and release of microparticles. Microparticles express the blood group Duffy antigen known to bind multiple inflammatory chemokines, but the functional chemokine binding properties of microparticles are not known.

STUDY DESIGN AND METHODS: We determined whether storage-induced microparticles show inflammatory chemokine binding through the expression of the Duffy antigen, comparing the binding properties to intact RBCs, and assessed microparticle interactions with platelets (PLTs) that release chemokines upon activation.

RESULTS: Intact RBCs retained similar equilibrium dissociation constants for CCL2 (Kd = 7.4 ± 0.9 nmol/L), CXCL8 (Kd = 7.9 ± 1.0 nmol/L), and CXCL1 (Kd = 4.4 ± 1.0 nmol/L) throughout storage. In contrast, microparticles increased in relative counts with storage, showed higher percentages of surface phosphatidylserine, and demonstrated impaired Duffy-dependent chemokine binding affinity with wider variability in dissociation constant for CXCL1(Kd = 362 ± 328 nmol/L; range, 0.6-2000 nmol/L). The altered chemokine binding affinity of RBC microparticles was associated with a propensity to release ligand upon incubation with PLTs. Relative quantification of microparticles, based on criteria of glycophorin A expression and size, underestimated particle numbers with functional chemokine binding, suggesting that glycophorin A–negative particles and nanoparticles contribute to overall chemokine binding capacity.

CONCLUSION: Microparticle burden in transfusates, as determined by functional chemokine binding, is considerable. Altered membrane properties of RBC microparticles enhance PLT interactions to increase inflammatory chemokine bioavailability in vitro.

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