Functional characteristics of apheresis-derived platelets treated with ultraviolet light combined with either amotosalen-HCl (S-59) or riboflavin (vitamin B2) for pathogen-reduction

Background To examine if different pathogen‐reduction technologies (PRTs) induce different degrees of platelet (PLT) storage lesion. Design Twenty‐seven split triple‐dose apheresis PLTs were PRT treated using ultraviolet light with either riboflavin (M) or psoralen (I) or remained untreated (C). Samples taken on days (d) 0 to 8 were analysed for PLT count, blood gas (pH, pO2 and pCO2), metabolism (lactate, glucose, ATP content), in vitro function [swirling, hypotonic shock response (HSR) and aggregation], activation (p‐selectin expression) and cellular integrity (JC‐1 signal, annexin A5 release). Results Platelet counts of all study groups remained unchanged during storage indicating that PRT treatment did not induce relevant cell lysis. Although M units demonstrated the highest values for HSR until d5, PRT treatment lowered all parameters examined with significant differences to untreated controls by d7 of storage. During final storage, M was significantly superior over I for HSR, aggregation with TRAP‐6 as agonist (collagen was similar), annexin A5 release and JC‐1 signal. Regarding blood gas and metabolic analysis, the most evident effect of PRT was an elevated glycolytic flux combined with higher acidity due to increased lactate accumulation. Most likely due to impaired O2 consumption, pH and ATP decreased more rapidly in I relative to C and M. Conclusion Pathogen reduction technology‐treated PLTs remained comparable to untreated units throughout 7 days of storage. Mitochondria‐based oxidative respiration appeared up‐regulated after the riboflavin‐based PRT. Compared to the psoralen‐based PRT, this resulted in significantly better ATP maintenance and in vitro function during the last storage period (d7, d8).