Pooling, room temperature, and extended storage time increase the release of adult‐specific biologic response modifiers in platelet concentrates: a hidden transfusion risk for neonates?

BACKGROUND Adult donor platelets (PLTs) are frequently transfused to prevent or stop bleeding in neonates with thrombocytopenia. There is evidence for PLT transfusion–related morbidity and mortality, leading to the hypothesis on immunomodulatory effects of transfusing adult PLTs into neonates. Candidate factors are biologic response modifiers (BRMs) that are expressed at higher rates in adult than in neonatal PLTs. This study investigated whether storage conditions or preparation methods impact on the release of those differentially expressed BRMs. STUDY DESIGN AND METHODS Pooled PLT concentrates (PCs) and apheresis PCs (APCs) were stored under agitation for up to 7 days at room temperature (RT) or at 2 to 8°C. The BRMs CCL5/RANTES, TGFβ1, TSP1, and DKK1 were measured in PCsʼ supernatant, lysate, and corresponding plasma. PLT function was assessed by light transmission aggregometry. RESULTS Concerning the preparation method, higher concentrations of DKK1 were found in pooled PCs compared to APCs. In supernatants, the concentrations of CCL5, TGFβ1, TSP1, and DKK1 significantly increased, both over standard (≤4 days) and over extended storage times (7 days). Each of the four BRMs showed an up to twofold increase in concentration after storage at RT compared to cold storage (CS). There was no difference in the aggregation capacity. CONCLUSION This analysis shows that the release of adult‐specific BRMs during storage is lowest in short‐ and CS APCs. Our study points to strategies for reducing the exposure of sick neonates to BRMs that can be specifically associated to PLT transfusion–related morbidity.