In vitro Quality of Platelets with Low Plasma Carryover Treated with Ultraviolet C Light for Pathogen Inactivation

Abstract

Background: The THERAFLEX UV-Platelets system uses shortwave ultraviolet C light (UVC, 254 nm) to inactivate pathogens in platelet components. Plasma carryover influences pathogen inactivation and platelet quality following treatment. The plasma carryover in the standard platelets produced by our institution are below the intended specification (<30%). Methods: A pool and split study was carried out comparing untreated and UVC-treated platelets with <30% plasma carryover (n = 10 pairs). This data was compared to components that met specifications (>30% plasma). The platelets were tested over storage for in vitro quality. Results: Platelet metabolism was accelerated following UVC treatment, as demonstrated by increased glucose consumption and lactate production. UVC treatment caused increased externalization of phosphatidylserine on platelets and microparticles, activation of the GPIIb/IIIa receptor (PAC-1 binding), and reduced hypotonic shock response. Platelet function, as measured with thrombelastogram, was not affected by UVC treatment. Components with <30% plasma were similar to those meeting specification with the exception of enhanced glycolytic metabolism. Conclusion: This in vitro analysis demonstrates that treatment of platelets with <30% plasma carryover with the THERAFLEX UV-Platelets system affects some aspects of platelet metabolism and activation, although in vitro platelet function was not negatively impacted. This study also provides evidence that the treatment specifications of plasma carryover could be extended to below 30%.

The impact of refrigerated storage of UVC pathogen inactivated platelet concentrates on in vitro platelet quality parameters

“…Cold‐storage is known to induce a rapid morphological change in platelets, from a discoid to a spheroid morphology, resulting in increased MPV, loss of platelet swirl and reduced HSR . UVC‐treatment has similar effects on the MPV and HSR . In the individual treatment arms, the MPV remained constant after the initial insult (UVC treatment or cold storage) on day 2, whereas the MPV continued to increase in the cold‐UVC platelets, suggesting it may be due to more than just a morphological change.…”

“…Currently there is international interest in both cold‐storage and different PI systems as strategies to alleviate issues related to RT storage of platelets . UVC‐treatment is known to affect standard in vitro quality parameters, however, most changes are small and do not become evident until later in storage . It was hypothesised that cold‐storage of UVC‐treated platelets may reduce some of the effects associated with RT storage of PI‐treated platelets in the hope of extending the shelf‐life.…”

“…UVC‐PI combines UVC light (target 254 nm) with strong agitation to inactivate pathogens . However, UVC‐PI treatment also alters aspects of platelet quality, including acceleration of glycolytic metabolism, increased phosphatidylserine exposure and activation of the GPIIb/IIIa receptor .…”

Is a platelet suntan the answer?

“…It is therefore not surprising that the effects on platelet metabolic state, activation level, and recovery and survival differ among the PR methods. UVC treatment was shown to increase platelet glucose consumption and lactate production when plasma carryover is less than 30%; however, only a trend toward increased platelet metabolism was observed when more than 30% plasma was present . The reduced effects on platelet metabolic rate when more than 30% plasma is present are likely due to UVC absorbance by plasma proteins and other plasma constituents.…”

Could Microparticles Be the Universal Quality Indicator for Platelet Viability and Function?

“…Because the emphasis is to detect degradation from the beginning to the end of the current 5-day shelf life [5, 6], the resolution of current quality measures has been tuned to be high for small changes on the “resting/viable” end of the quality spectrum but becomes low on the “activated/functional” end of the quality spectrum. Additional changes are seen upon extended shelf life which become more important as bacterially tested or pathogen inactivated platelets may be stored for 7 days.…”