A more efficient preparation system for HLA‐eliminated platelets

Abstract

Background and objectives Although HLA‐eliminated platelets can facilitate transfusions to patients possessing HLA antibodies, no such products are currently available commercially perhaps because the platelet collection rate is not yet economically viable. We have improved this process’ efficiency by employing a hollow‐fibre system at the last step of the production process after an acid and a reaction buffer have been washed out conventionally by centrifugation. Materials and methods HLA‐eliminated platelets were prepared via four distinct steps: chilled on ice, treated with an acid solution, diluted and finally washed using the hollow‐fibre system. The efficiency of this platelet recovery process was determined. The resulting products’ platelet characteristics, including a capacity for HLA expression, were evaluated in vitro and compared in detail to their corresponding originals. Results The average efficiency of platelet recovery was 91%. Although the expression levels of CD62P, a molecular marker for platelet activation, were approximately threefold higher on new platelets than on the original platelets, their HLA expression levels were lower. The phagocytosis assay, with monoclonal antibodies and cognate HLA antibody‐containing sera, suggested that HLA‐ABC molecules on the cell surface were sufficiently removed. The platelet functions, including the agonist‐induced aggregability and adherence/aggregability of the collagen‐coated plates under certain conditions, were conserved and not significantly different from the original ones. Conclusion We propose a novel preparation system for producing HLA‐eliminated platelets without centrifugation, which ensures a highly efficient, and therefore, much more economical method of platelet recovery that also retains their key functionality.

Dual preparation of plasma and platelet concentrates in platelet additive solution from platelet concentrates in plasma using a novel filtration system

“…A hollow-fibre system has recently been developed in Japan for the preparation of washed PCs and HLA-eliminated PCs from PCs suspended in plasma [17,18]. This development drove us to explore the possibility that the same hollow-fibre system in combination with the cross-flow technique can achieve simultaneous dual preparations of PAS-PC and flow-through plasma.…”

“…Agonist-induced platelet aggregation was measured as previously described [18]. Briefly, platelet samples were suspended in an equal mixture of type AB plasma and PAS-E to obtain a final platelet count of 300 Â 10 3 /μl (PRP).…”

“…Platelet activation by processing during centrifugation and/or shear stress (pumps) during collection are considered plausible causes of platelet aggregation [15]. Utilizing a hollow-fibre system devoid of a centrifugation step, we recently reported the successful preparation of washed PCs and HLAeliminated PCs from plasma-suspended PCs, with very low platelet activation and high platelet count recovery [17,18]. In line with these studies, we report here an efficient platform for dual preparation of PAS-PC and platelet-poor plasma using a hollow-fibre system coupled with a cross-flow filtration technique.…”

UV light-emitting diode (UV-LED) at 265 nm as a potential light source for disinfecting human platelet concentrates

“…Surface expression analysis of CD62P (granule membrane protein, GMP-140), which is expressed on the platelet surface when activated platelets release granules, was carried out as previously described [ 29 ]. In this study, TRAP-stimulated platelets were used as positive controls for full activation of platelets.…”

“…Collagen tips were prepared by following the manufacturer’s instructions (Cellix Ltd., Dublin, Ireland). In brief, 50 μL of the 50 μg/mL collagen reagent Horm (Moriya Sangyo) was loaded on a Vena8 microfluidic biochip (height, width, and length of each channel were 0.1, 0.4, and 28 mm, respectively) (Cellix Ltd.), incubated at 37°C for at least 1 h, and then washed with PAS-E (formerly PAS-IIIM; the composition of this solution is described in [ 29 ]) before use. Platelet samples were diluted to a platelet concentration of 5.0 × 10 4 /μL by adding AB plasma, 3 mM calcium chloride, and 10 μM mepacrine (Wako Chemical, Osaka).…”