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Prion protein release in apheresis platelet concentrates is associated with platelet activation and lysis
Author(s) -
Bessos H.,
Drummond O.,
Prowse C.,
Turner M.,
MacGregor I.
Publication year - 2000
Publication title -
transfusion medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.471
H-Index - 59
eISSN - 1365-3148
pISSN - 0958-7578
DOI - 10.1046/j.1365-3148.2000.00261-2.x
Subject(s) - platelet , apheresis , lysis , chemistry , andrology , lactate dehydrogenase , plateletpheresis , granule (geology) , platelet activation , microbiology and biotechnology , immunology , biochemistry , medicine , biology , enzyme , paleontology
Studies using a time‐resolved fluoroimmuno‐assay (DELFIA®) have shown that platelets and plasma are the main compartments of the normal isoform of prion protein (PrP c ) in human blood. The aim of the present study was to monitor PrP c levels in various fractions of apheresis platelet concentrates (PC) during storage and to assess the association of this release with α granule protein β‐thrombo‐globulin (BTG) and cytoplasmic lactate dehydrogenase (LDH) as cell activation and cell lysis markers, respectively. Six apheresis PC were obtained from volunteer donors using Haemonetics MCS and stored up to 10 days. 7–9 mL samples were aseptically collected from each PC on days 1, 2, 3, 4, 5, 8, and 10 of storage. Platelet poor plasma (PPP) and platelets (P) were prepared and the PPP split into two equal fractions, one of which was centrifuged at 40,000g for 2 h at 4 °C to remove microparticles (MP) [high spun plasma (HSP)]. The results showed that the mean overall levels of PrP c during storage remained within 15% of day 1 levels. In contrast, the mean levels in P significantly decreased to 46% day 1 levels by day 10 of storage ( P < 0·01), while the corresponding levels in plasma significantly rose by up to 329% ( P < 0·01). Moreover, although MP‐bound PrP c was released during storage, it was increasingly superceded by soluble prion protein. PrP c and BTG release exhibited very similar patterns, both showing a significant rise in PPP and HSP ( P < 0·01). In contrast, LDH showed a significant rise in HSP only towards the end of the storage period ( P < 0·01). These results indicate that PrP c is released from platelets during storage of PCs and that this release is probably due mainly to platelet activation and α‐granule release in the first few days of storage. The release of PrP c is apparently reinforced through cell lysis, and is increasingly comprised of soluble prion proteins, at longer storage periods.