Basophil activation test for allergic and febrile non‐haemolytic transfusion reactions among paediatric patients with haematological or oncological disease

Background and Objectives Allergic transfusion reactions (ATRs) and febrile non‐haemolytic transfusion reactions (FNHTRs) are common, although their mechanisms remain unclear. Immunoglobulin E (IgE)‐mediated type I hypersensitivity may be involved in the pathogenesis of ATR. A basophil activation test (BAT) may help elucidate this process. Materials and Methods The BAT was based on peripheral blood samples from paediatric patients with a haematological or oncological disease and on samples of residual blood products transfused in each case. Dasatinib was used to evaluate whether basophil activation was mediated by an IgE‐dependent pathway. Results Twenty‐seven patients with and 19 patients without ATR/FNHTR were included in this study, respectively. The median BAT values associated with ATR‐ (n = 41) and FNHTR‐causing (n = 5) blood products were 22.1% (range = 6.1%–77.0%) and 27.8% (range = 15.2%–47.8%), respectively, which were higher than the median value of 8.5% (range = 1.1%–40.9%) observed in blood products without a transfusion reaction. Dasatinib suppressed basophil activity. BAT values were comparable in patients with ATR regardless of severity. Meanwhile, BAT values analysed with blood products non‐causal for ATR/FNHTR were higher in patients with ATR/FNHTR than in those without. Conclusion The IgE‐mediated type I hypersensitivity may be involved in the pathogenesis of ATR and FNHTR. BAT analyses may help elucidate the underlying mechanisms and identify patients at risk.