The fXe treatment inactivated bacteria in apheresis PCs in plasma without additional chemical compounds. The fXe-treated PCs retained acceptable in vitro properties of PC quality and PLT functionality.

Xe flash phototreatment could prevent bacterial proliferation and reduce HIV-1 infectivity in 100% plasma PCs without any additional compounds, but enhanced PLT storage lesions. Further improvement is required to increase the potency of pathogen inactivation with reducing PLT damage.

BACKGROUND: Our previous study showed that ultraviolet C (UVC) from xenon (Xe) flash without any photoreactive compounds inactivated bacteria in platelet concentrates (PCs) with less damage to platelets (PLTs) as compared with Xe flash containing ultraviolet A, ultraviolet B, and visible light. Here, we report a UVC irradiation system for PCs under flow conditions consisting of a flow path-irradiation sheet, a peristaltic pump, and a collection bag. STUDY DESIGN AND METHODS: Plateletconcentrates containing Ringerʼs solution (R-PCs) inoculated with bacteria were injected into a flow path sheet using a peristaltic pump, being irradiated with UVC from Xe flash. The quality of the irradiated PCs containing platelet additive solution (PAS-PCs) was assessed based on PC variables, PLT surface markers, and aggregation ability. RESULTS: Streptococcus dysgalactiae (12 tests) andEscherichia coli (11) were all negative on bacterial culture, while Staphylococcus aureus (12) and Klebsiella pneumoniae (14) grew in one and two R-PCs, respectively. Bacillus cereus spores were inactivated in 7 of 12 R-PCs. PC variables became significantly different between irradiated and nonirradiated PAS-PCs. P-selectin, first procaspase-activating compound (PAC-1) binding, and phosphatidylserine increased by irradiation. Aggregability stimulated by adenosine diphosphate, collagen, or thromboxane A 2 increased in the irradiated PAS-PCs, while that by thrombin became smaller compared with nonirradiated controls.CONCLUSION: This newly developed system inactivated bacteria including spores in R-PCs. PAS-PCs irradiated by this system retained acceptable in vitro quality and aggregability. Usage of a peristaltic pump instead of agitator during irradiation may enable this system to be directly combined with an apheresis blood cell separator. E ven in the developed countries, transfusiontransmitted bacterial infection remains a serious lifethreatening adverse event following the transfusion of platelet concentrates (PCs). PC stored at a temperature of 20 to 24°C is susceptible to bacterial growth, although its incidence is quite low. In 2017, a fatal sepsis case caused by the transfusion of a PC contaminated with Escherichia coli was reported to the Japanese Red Cross Blood Service Headquarters, 1 although efforts to eliminate bacterial contamination have been promoted by a combination of improved skin disinfection and the diversion of initial blood flow at blood donation, 2 in addition to a short shelf life of PCs (3 days) in Japan.A longer shelf life of PCs (≥5 days) in many countries makes inventory management easier. Automated culture systems, such as BacT/ALERT 3D (BioMérieux), have been widely implemented in those countries for the detection of bacterial contamination in PCs by sampling an aliquot of PCs within ABBREVIATIONS: ADP = adenosine diphosphate; ANOVA = analysis of variance; FDA = US Food and Drug Administration; FITC = fluorescein isothiocyanate; HSR = hypotonic shock response; ihPAS = in-house platelet additive solution; MPV = mean pla...